# A race to failure: Halogen process, filament temp and envelope glass.



## Icebreak (Nov 11, 2006)

*A race to failure: Fill gas, filament temp and envelope glass.*

From time to time incandescent lamp failures are evaluated and discussed. I have a few ideas and thought it might be helpful to put those ideas in one post.

The halogen process of re-depositing gaseous tungsten from the gaseous tungsten/halogen compound back on to the filament is delicate. Too low low of a temperature and it begins to fail. To high of a temperature and it begins to fail. If the fill gas escapes due to a flaw in the glass envelope the process will fail.

If the lamp is being driven too hard the filament may become too hot. If the filament has a thin spot on it that spot will become too hot. If the filament has some shock fatigue that area may become too hot.

If the glass envelope is dirty or has the oils and salts from fingerprints on it the envelope can have a molecular break down. Offending dirt, crud or what have you may darken due to heat and not allow the IR to properly escape the lamp causing the interior of the lamp to overheat and fail the halogen process, the filament or the glass envelope. The fingerprint oil may cook up and create a hot spot on the glass causing it to fail.

It’s difficult to know why a lamp fails because sometimes there is a race to failure. The envelope, the halogen process or the filament may win. When the race is over and all these components have failed it’s a challenge to know who won and who came in second due to cascade failure.

Here’s a good WA1185

Good WA1185




Here’s a blown WA1185 and I’m guessing it was an envelope failure. Notice the potting looks altered in one area. Take note of the yellowish residue on the envelope.

Blown WA1185 with yellowish residue




I don’t know exactly what form of tungsten that is but it looks like:

Tungsten Trioxide (WO3)




Here is a blue and white WA1185 that failed. I think that was a race to failure between the halogen cycle and the filament. I was driving it very hard. I think the filament became too hot and began to fail the halogen cycle but the filament was destined to melt.

Blue and White WA1185




I don’t know exactly what form of tungsten the white residue is but it looks like:

Ammonium Paratungstate (APT) [(NH4)10W12O41 . 5 H2O]




When I started seeing these types of anomalies I began to believe I was understanding some things that could be the beginning of a speculation, possibly a theory. The dreaded fingerprint oil may not be the big culprit I first thought. 

Then I saw a Welch Alynn fail in a way I’d never seen or heard of. I was shining it at the ceiling, a can’t remember why, and the beam turned partially orange and partially white. Then the beam started to develop an area of blue in it as well. A little white, even more orange and a lot of gorgeous blue. I turned the light off and was a little amazed at what I saw. I took the lamp out and examined it. I realized that I had a snapshot of a race to failure that was halted before total failure took place. The halogen process, the filament and the glass envelope were all competing to fail. The lamp still worked and the filament was still shiny.

Blue Globe WA1185 still working


+

There has been some agreed upon speculation and some conclusions drawn that Carley’s potting process is the cause of most HotWire explosions and failures. I think that’s a valid opinion but I don’t think we can blame most failures on the Carley potting process. Some, yes but not most.

Then I saw that AWR posted something very similar with a bi-pin WA1185. I’d bet he was driving it pretty hard but his torch was left face down for a time which heated up the whole system. It looks like a similar snapshot of a race to failure:

AWR’s Blue Globe




Then fivemega let us know about something very similar. It’s a little difficult to detect the blue color but it’s there. fivemega stated it was blue and also let us know it was still working.

fivemega’s Blue WA1331




So I began to think we can’t blame most failures on Carley or Welch-Alynn. We are driving these puppies hard so we are often requesting too much from all the components of an incandescent lamp.

The ROP cannot escape the race to failure. Here’s 700club’s beautiful failure:

700club’s Blue ROP






That’s nice. It could have been a little too well overdriven but I think there was a flaw in the filament that caused this. It could have easily been an envelope problem that allowed the fill gas to escape. I don’t know.

Then we see Pydpiper's Surefire. Size15's explains the possibility of lamp exploding. 

Blue SureFire MN16.






I don't know exactly what form of tungsten this royal blue seen in these failures is but it does look somewhat like this:

Tungsten Blue Oxide (TBO; WO3-X)






So, I don’t have any final conclusions. I will just submit that understanding the halogen process and how all the other parts of the lamp can affect it may help in determining why some incandescent lamps fail. Sometimes it might be impossible to know what happened if the race to failure was a photo finish resulting in some real violent activity.

Violently exploded WA1185





***EDIT*** 01/01/2007 to add Colorado Fatboy's exploded bi-pin WA01185. It seems to corroborate js's theory of pin jarring. It seems to many that the left pin had been bent about a bit and after stresses were place on it the glass was stressed or fatigued and that it is the most likely cause of the exploding lamp. Here is Colorado Fatboy's thread. 





***END EDIT***

***EDIT*** 01/09/2007 To add Fluffster's bi-pin 1185 that glowed orange and turned blue seen in Fluffter's thread.






***END EDIT***

I’m not an EE and certainly not a chemist. I would like to know more about the chemistry of hot, gaseous tungsten. It may be the tell in incandescent lamp failures.

Thanks for reading this.

- Jeff


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## litho123 (Nov 11, 2006)

Excellent recap Jeff! :goodjob: 


 ... and good food for thought too. 


I missed a few failures that you recap in this thread.



My observation is that the rate of bursting bulbs is lower with bi-pin bulbs vs. potted bulbs. We are now attaining higher operating voltages (thru less resistance and the HotDriver) with bi-pin bulbs than we did with potted bulbs, driving the bulbs harder, shortening its life. Are we making it too short?

Hmmm... I like that phrase "A Race to Failure"


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## Icebreak (Nov 11, 2006)

litho123 said:


> My observation is that the rate of bursting bulbs is lower with bi-pin bulbs vs. potted bulbs. We are now attaining higher operating voltages (thru less resistance and the HotDriver) with bi-pin bulbs than we did with potted bulbs, driving the bulbs harder, shortening its life. Are we making it too short?



G.H. -

You would be the best authority for stats on the ratio of bursting bi-pin bulbs to potted bulbs. It makes sense that the potted lamps would fail more often. Bend one pin, attach it to the PR sidewall, attach the other pin to the annode section of the PR then dump a bunch of ceramic cement in there. That's a large extra parameter to introduce into the equation.

I've been attaining higher power (like others) using RC type batts in series running your potted bulbs with good success. I'm getting much more than ten hours out of them so if the filaments are virtual liquid while at task that's fine.

Thank you for the kind words.


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## Timson (Nov 11, 2006)

Icebreak, 
Nice write-up.

It's a good and timely reminder to pay extra respect to these overdriven hotwire lamps that we take for 'the norm'.

They are potentially dangerous and should be operated with care - only by persons who know and understand the associated risks.


Tim.


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## js (Nov 11, 2006)

First of all, good thread, Ice Break. Good topic of discussion.

However, all modern halogen lamps have the elements tweaked just right so that the halogen cycle functions over the full range of operating temperatures of the lamp.

Next, even if the halogen cycle wasn't working, it wouldn't cause failure. In fact, the SureFire high pressure xenon lamps intentionally reduce the halogen compents of the fill gas in order to be able to get a higher pressure. This results in a more efficient lamp, but one which still does not blacken as fast as a straight xenon or krypton fill lamp with NO halogen compent.

Finger prints do not cause a problem by trapping heat. They cause a problem because the oil chemically reacts with the glass at high temperature, changing its make-up into a compound which is softer than the hard glass it used to be, causing failure of the bulb envelope at that point.

Thin spots in the filament, or physical shocks to the filament, WILL NOT CAUSE AN EXPLOSION. They cause an "insta-flash" at turn on, or they break a lit filament, causing the lamp to go out. But not an explosion.

Besides the good lamp you picutre, *every single lamp shown in your post had a failure in the ENVELOPE*. Any time you see those colorful, dirty, ugly looking lamps, you know that the fill gas leaked out, and oxygen leaked in, and some mixture of the two reacted with the tungsten filament and with the filament support wires.

This is not the fault of the halogen cycle or the fill gas.

This is not the fault of the filament.

This is not the fault of over-driving.

How about that last one? Over-driving. Well, for starters, I have overdriven lamps pretty darn hard and never seen one explode due to it. In fact, one of the best ways to find the operating voltage of a lamp is to put it on a bench supply and push it higher and higher until it reaches vaporization. At that point, you know the CCT, and can read off the voltage from the bench supply. This wouldn't be a useful procedure if the lamps tended to explode first!

Second, the IRC lamps made by Osram have an infra-red reflective coating which traps the heat, insulting the lamp, thus pushing up the envelope temperature way past the sort of temperatures we would find even in our over-driven WA lamps. (Not because the FILAMENT is hotter, but because the temperature gradient from filament to wall is shallower)

Over-driving, in my opinion, isn't the issue.

What is or are the issues, then?

1. I must disagree with you and say that Carley PR-base potted WA lamps fail because of the stress put on them during the PR-base potting. One lead must be bent way back during the process. AND, it is probably done at Carley's plant in Mexico and it wouldn't surprise me if the workers just handle the lamps with bare hands and then all are quickly chemically cleaned at the end of the process--thus leaving finger oil on the envelope _under neath the surface of the potting_!

2. The other thought that comes to mind is physical stress and damage to the glass envelope DURING SHIPING. Welch Allyn ships lamps in a nice foam matrix, completely protected from vibration and shock. But, I have received WA lamps from CPFers that were all just thrown lose into a paper envlope--10 of them! That can't be good, I don't think. It might be OK, but it might not. Shipping in foam or bubble wrap, with no lamp touching another is best.

So, in short, I like your thread, but I reach a totally different conclusion.


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## Icebreak (Nov 11, 2006)

[quoting js and inserting text]

First of all, good thread, Ice Break. Good topic of discussion.

Hello, Jim and thanks. I think this stuff is interesting. I've expressed a lot of speculation here and most of it is not very clearly stated. I'm trying to understand all the possible failures. I've used "race to failure" as a way to help understand what's going on. I've mentioned the halogen cycle failing. It _does_ fail I just wanted to know when. I think I'm right about some of this stuff and wrong about some of it.

However, all modern halogen lamps have the elements tweaked just right so that the halogen cycle functions over the full range of operating temperatures of the lamp.

This is a challenge to except. I'm not saying it isn't true. You probably know this as fact from your work with real engineers. I'm just honestly saying it's hard to except.

Next, even if the halogen cycle wasn't working, it wouldn't cause failure. In fact, the SureFire high pressure xenon lamps intentionally reduce the halogen compents of the fill gas in order to be able to get a higher pressure. This results in a more efficient lamp, but one which still does not blacken as fast as a straight xenon or krypton fill lamp with NO halogen compent.

Understood. I knew performance could be increased by tweaking the gas fill from reading posts by Greg, Bill, yourself and others. It's a good thing to know. I think litho123's CA1499 design was utilizing a similar concept.

Finger prints do not cause a problem by trapping heat. They cause a problem because the oil chemically reacts with the glass at high temperature, changing its make-up into a compound which is softer than the hard glass it used to be, causing failure of the bulb envelope at that point.

The following will at first sound like I'm disagreeing but you'll see near the end that I'm not. For clarification, fingerprint oil can cause three types of envelope failure.

1.) Molecular change in the quartz envelope. The envelope is vitreous quartz. Sodium in fingerprint oil will catalyze its devitrification/crystallization to crystobalite. When the envelope cools, differential contraction of crystobalite vs amorphous silica cracks the envelope.

2.) A greasy hot spot can cook up and sometimes fail the envelope. Sometimes the envelope will grow a bulbous form at the point of contact.

3.) The organics in fingerprint oil will pyrolyze to char, creating hotspots on the envelope which will soften and fail at operating temperature.

I don't think the 2nd or 3rd type of failure occur with our flashlights. Those failures take place in automobile lamps and stage lights etc. I used to think that the 2nd type did but I no longer think this. So, for the purposes of this discussion, I'm in agreement with you the the 1st type of failure, the one you mentioned, can and will happen. I just don't think it is the cause as often as CPF conventional wisdom would indicate. I've purposefully tested this getting finger print oil all over a Welch Allyn lamp, turning it on and watching it smoke until all the oil was gone. Probably a little lucky on that test but I thought I'd mention it to add to the discussion.

Thin spots in the filament, or physical shocks to the filament, WILL NOT CAUSE AN EXPLOSION. They cause an "insta-flash" at turn on, or they break a lit filament, causing the lamp to go out. But not an explosion.

Besides the good lamp you picutre, *every single lamp shown in your post had a failure in the ENVELOPE*. Any time you see those colorful, dirty, ugly looking lamps, you know that the fill gas leaked out, and oxygen leaked in, and some mixture of the two reacted with the tungsten filament and with the filament support wires.

This is not the fault of the halogen cycle or the fill gas.

This is not the fault of the filament.

This is not the fault of over-driving.

How about that last one? Over-driving. Well, for starters, I have overdriven lamps pretty darn hard and never seen one explode due to it. In fact, one of the best ways to find the operating voltage of a lamp is to put it on a bench supply and push it higher and higher until it reaches vaporization. At that point, you know the CCT, and can read off the voltage from the bench supply. This wouldn't be a useful procedure if the lamps tended to explode first!

Second, the IRC lamps made by Osram have an infra-red reflective coating which traps the heat, insulting the lamp, thus pushing up the envelope temperature way past the sort of temperatures we would find even in our over-driven WA lamps. (Not because the FILAMENT is hotter, but because the temperature gradient from filament to wall is shallower)

Over-driving, in my opinion, isn't the issue.

I have found nothing that supports my speculation that indicated a filament problem can cause an explosion. However, I did find quite a bit of information that supports exactly what you said.

What is or are the issues, then?

1. I must disagree with you and say that Carley PR-base potted WA lamps fail because of the stress put on them during the PR-base potting. One lead must be bent way back during the process. AND, it is probably done at Carley's plant in Mexico and it wouldn't surprise me if the workers just handle the lamps with bare hands and then all are quickly chemically cleaned at the end of the process--thus leaving finger oil on the envelope _under neath the surface of the potting_!

I'm going to somewhat disagree with this. I don't think they _always_ fail due to what you've noted. The bi-pin WA lamps shown above were not potted yet did fail. It could be that some CA potted WA lamps fail for the same reason the bi-pins did. AWR's bi-pin 1185 and my potted 1185 look almost the same.

2. The other thought that comes to mind is physical stress and damage to the glass envelope DURING SHIPING. Welch Allyn ships lamps in a nice foam matrix, completely protected from vibration and shock. But, I have received WA lamps from CPFers that were all just thrown lose into a paper envlope--10 of them! That can't be good, I don't think. It might be OK, but it might not. Shipping in foam or bubble wrap, with no lamp touching another is best.

I got some potted lamps that had flattened flanges because the mailing envelope was processed by a machine.

So, in short, I like your thread, but I reach a totally different conclusion.

Thanks.

Requoting you here because this is significant:

*every single lamp shown in your post had a failure in the ENVELOPE

*I agree. Taking this a little further...I don't think that fingerprint oil is the problem in most cases. I think envelope failure is the problem in most cases. Why envelopes fail is a question I want to continue to persue. Why lamps explode is a question I want to continue to persue.

Here's something I've learned:

When a lamp envelope is broken while the filament is ON, or the filament is energized subsequent to the envelope having been broken, the compounds which form and their colors are:

Tungsten Nitride, (WN2), Brown
Tungsten Dioxide, (WO2), Brown
Tungsten Pentoxide, (W2O5), Blue-violet
Tungsten Trioxide, (WO3), Yellow

* When a lamp envelope is broken while the filament is on, even briefly, you get yellow Tungsten Trioxide.

When a lamp envelope has failed previously to the filament being energized you get blue-violet Tungsten Pentoxide.

ref Answers.com light bulb definition

ref Technical review discussion, Mechanical Forensics Engineering Services
* 
From this I’ll submit that all those purplish blue bulbs had an existing envelope failure. That failure could have occured for several reasons including a failure at the factory. The fill process at the factory may have failed. If so, the halogen process never had much of a chance to endure for the rated life of the lamp. I’ve wanted to know the exact chemical make-up of these failures resulting in yellow residue and blue-violet residue and how they fit into to the race to failure for sometime now.

I’ve learned a lot today. Thank you for your help.

[/quoting js and inserting text]


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## js (Nov 14, 2006)

Icebreak,

Nice reply! Thoughtful and precise. Good stuff.

The only nitpicking comment I would make is concerning your last paragraph above that starts with "From this I'll submit . . .". I just want to point out that an integrity failure in the envelope that allows fill gas to leak out and/or oxygen to leak in, has nothing to do with the halogen cycle. Straight Xenon fill lamps, with no bromine or iodine halogen trace will fail badly of the envelope is compromised. No halogen process involved.

As for my reference source for the statement about the halogen cycle working over the full range of operating voltages, from low CCT to high CCT, it comes from Osram's "Tungsten Halogen Low Voltage Lamps Photo Optics":



> When incandescent lamps are dimmed, they operate at a wattage lower than their rated wattage. In *conventional incandescent lamps* i.e. lamps without halogen, the response to dimming is immediate and direct: at the reduced temperature, the filament vaporizes less, which increase the life of the filament and reduces blackening of the lamp bulb. The lower color temperature and reduced efficacy may be disadvantageous. When heavily dimmed, a lamp will only consume electrical power and will not give out light, but only heat. In *halogen lamps* the relationships are less simple and clear-cut because of the chemical cycle. A certain minimum wall temperature is necessary for the vaporized tungsten to be returned from the inner bulb wall. The wall temperature depends on the power input to the lamp, and if this is reduced, the wall temperature drops too.
> 
> In earlier tungsten-halogen lamps it was possible for the cycle to stop and the lamp to blacken when the wattage was considerably reduced ("heavily dimmed"). In modern halogen lamps on the other hand, ways have been found of conducting the cycle so that no blackening takes place at any level of dimming. As fig. 26 (not show here!) shows, the cycle continues functioning down to filament temperatures so low that the evaporation rate of the tungsten filament is insignificant in terms of blackening, Modern halogen lamps - at least those for photo-optic applications - are dimproof.



(from page 26).

But it's kind of beside the point, anyway, as we flashaholics almost never UNDERDRIVE out lamps, we overdrive them, and thus the wall temperatures will be HIGHER, and the halogen cycle even happier and more effective.

As I pointed out before, the presense of a halogen such as iodine or bromine, enables the halogen cycle--HOWEVER, it also limits the pressure of the fill gas attainable. If you have enough of a halogen trace to totally prevent blackening, you are unable to push the pressure up as high as you could in a straight xenon fill lamp. Check out the ratings of the Carley lamps, halgoen vs. non-halogen, and you will see that in general, the non-halogen ones are better. I used to wonder why in the world a company would go to the trouble of using xenon fill gas and NOT use a halogen, but then I learned about the pressure issue. At the highest pressures, the halogen will attack the filament supports and corrode them, so there is a trade off.

Sure-Fire, it seems chooses to strike a balance and have enough of a halogen present to slow blackening down, but not enough to prevent it, thus allowing them to acheive higher pressures and greater efficiencies. Thus, I can show you a photo of my MA02 which I used for over a year, through many sets of batteries, that exhibits blackening. I can't show you a WA lamp of mine that has ever blackened, though!

Getting back to the structural failure issue, I left out a lot in my post. Let me get to it now.

First of all, I have never seen or heard about a TigerLight, or SL-20X or SL-35X lamp assembly exploding. Why? And when I started the TL upgrades, I started by overdriving the SL-35X LA to the point where we were flashing them left and right. I lost a lot of money that way, actually! LOL! But we never exploded one. I think the reason is that the potting surrounding the pins and entire bottom of the lamp *physically protects the integrity of the envelope* when people bend or stress the pins.

Same goes for my ring-potted lamps (link in sig-line). I have potted over 200 lamps in my career, and other than at the start, due to finger oil and a flaw in my technique, I have *never experienced, or even heard of someone exploding one of my ring-potted lamps*. Plenty of people have isnta-flashed them, but never had anyone report an explosion.

Again, I think this is due to the ridgidity and support offered by the potting surrounding the bottom of the lamp. Pins in a TL get bent all over the place, but still the LA is OK. And this is why, I think.

A bare bi-pin, on the other hand, even one that has been properly packed and shipped and handled, undergoes plenty of stress when being inserted into a bi-pin holder, or nudged into position for the best beam profile. Or even just when experiencing the usual knocks and drops and shocks. Those get transmitted directly to the pin/glass interface, which is the weakest structural point on the lamp.

Now this SHOULD mean that a PR-base potted lamp should also be protected, but it does not due to the fact that it is pre-stressed in the very process of being potted into a PR-base.

As for Carley, never underestimate their ability to screw things up. The stories I could tell you . . .


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## Icebreak (Nov 15, 2006)

Aha! and aha again and again.

That's excellent information coupled with easily understandable explanations.

Thanks for your patience with my not wanting to let go of the halogen cycle as a contender. I'm thinking it should be replaced by "fill gas integrity".

When I was posting my response to your first response I also added another pic and link to Pydpiper's failing MN16 to my original post. I have a question about that. In that linked thread Pydpiper is cautioned to remove the blue MN16 because, since the gas fill has been compromised, the filament may vaporize causing the lamp to explode.

Is the possible vaporization of the filament causing an explosion unlikely? If I'm understanding what you've expressed, it would be more likely that because that lamp's fill gas has been compromised that the lamp system and ultimately the lamp's envelope would become too hot and begin to melt or fracture causing an explosion as a secondary failure of the envelope.

--------------

Jeff


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## js (Nov 15, 2006)

Icebreak,

Good question! Yes, I remember the thread.

Short answer: I don't know.

In that scenario, it really IS a race to failure, with several contenders! LOL! My guess would be that because the envelope already has an integrity failure that it will explode when (or if) the temperature reaches high enough levels to increase the pressure enough to blow it up. OR, the filament could just vaporize first. Either way, it was good advice given: "DON'T USE IT!!!"


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## litho123 (Nov 15, 2006)

Js – thanks for your comments. Insightful as always.


After re-reading this thread a couple of times, I was struck by the phrase you used “ENVELOPE failure” and started reviewing 

-Bi-pin vs. potted bulbs 
-Carley vs. WelchAllyn 
-the potting process 


It seems to me, in general, that  
-bi-pin bulbs tend to be less prone to ENVELOPE failure than potted bulbs. 
-Carley’s own potted bulbs tend to be less prone to ENVELOPE failure than WA bulbs potted by Carley.  


Why could that be? Both Carley and WA bulbs go thru the same potting process. 


The only visible differences between Carley and WA bulbs are: 

- SIZE: T2.5 vs. T2.25 
This 0.03” diameter difference is what causes slightly crooked potted WA bulbs.

- LEG length: Uncut leads (Carley: .65” – 1.0”) vs. pre-cut leads (WA specs: .20” min. to the bottom of the glass nub, it's slightly longer) 


Since there is such a difference in lead length I wonder if this could be a contributing factor for more ENVELOPE failure with potted WA bulbs? 

That there is more stress on the WA bulbs due to their shorter leads?

… Short leads …harder to bend … more drastic angle in order to contact side of PR base … more ENVELOPE stress. 
Carley's leads have so much excess that it's easier to work with when bending.

So, would longer leads on WA bulbs reduce the stress on the envelope during the potting process? 





js said:


> As for Carley, never underestimate their ability to screw things up. The stories I could tell you . . .



 


Bartender! :drunk:

I need another drink! 
another Carley wallbanger  and two aspirin to make this headache go away!  




:lolsign:


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## Icebreak (Nov 15, 2006)

Jim -

Another good answer. Thanks.

litho123 -

"So, would longer leads on WA bulbs reduce the stress on the envelope during the potting process?"

I know that was probably for js. It does seem to be likely and logical.

I'm beginning to see that a Carley potted WA is most likely to explode or have an envelope failure.

After that would be WA bipin that has been bent around for focus.

After that I don't know what LAs would be most likely to fail or explode but it sounds like SL, SF, Tiger, Pelican and maybe Mags are much less likely to fail or explode.

I like the Carley potted Welch Allyns because they are drop-ins and allow focusing by bending the PR flanges and not the pins. When they work they work very well.

I really like the litho123 designed CA potted CA1499.

For my purposes I think several trays of various js ring potted Welch Alynns would be good.

Thanks, gentlemen.

- Jeff


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## bwaites (Nov 15, 2006)

One point to remember, even Surefire lamps have failed and exploded and they AREN'T potted!

Bill


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## js (Nov 16, 2006)

litho123,

My guess is that for Carley lamps that are going to be potted, that they bend the pin *BEFORE* forming the glass envelope around it. In other words, it comes out of the facility with the pin already bent.

The WA lamps on the other hand, are bent after the fact.

Or it could be due to lead length, or lead thickness. I mean, the WA lamps we all want potted are higher power than anything Carley sells.



bwaites said:


> One point to remember, even Surefire lamps have failed and exploded and they AREN'T potted!



SF lamps are potted, Bill. All of them. Or did you mean PR-base potted lamps? Or did you mean SF lamps have failed and they "ARE" potted?

In any case, yes, any type of lamp from any company can experience explosive failure. This is why you should never run a bare lamp. Always run it inside of something so that if it does explode it will not blind you or injure you.

Another thought about the SF lamps, relative to the WA lamps, is that the SF lamps are higher presssure lamps than the WA lamps. And also are in pretty small envelopes for their power. Especially the MN20, for example. The TL lamp, for example, is like twice as big as the MN20 and not much over _half_ the power of the MN20. Thus you can imagine what the power density is inside the MN20 envelope. I don't know of a higher power density than that lamp.


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## Icebreak (Jan 2, 2007)

Just added Colorado Fatboy's exploded bulb to the original post and as a new post. The jury is still out but it's looking like it supports js's originial suspicion from a couple of years ago. It seems to many that the left pin had been bent about a bit and after stresses were placed on it the glass was stressed or fatigued and that it is the most likely cause of the exploding lamp

Colorado Fatboy's thread.


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## js (Jan 2, 2007)

Icebreaks sigline said:


> The oldtimers are forever bound to the universe of flashlights. They reside just above the torch lit stratosphere where the good photons pass by. As these oldtimers locomote on their appointed ways, occasionally an unusual glimmer from below catches their attention.
> 
> They may give a nod or a word.



Icebreak, I love your sig-line!


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## Icebreak (Jan 9, 2007)

Heh heh. It's cool when it happens. I've seen Doug S. around lately and man of mystery kogatana was posting over the holidays. I appreciate your dropping in on this thread from time to time.

Here's Fluffster's bi-pin 1185 that glowed orange and turned blue documented in Fluffster's thread. The pins look straight and parallel. Going on the color, it appears the lamp envelope was mostly evacuated then evactuated a little more during its failure. I'll go ask him if he's aware of installation or lateral focusing motions that may have stressed the pins or envelope.


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## Fluffster (Jan 10, 2007)

I don't think I stressed it at all. I you'd like to inspect it I can throw it in the mail for you.


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## Icebreak (Jan 11, 2007)

They didn’t look stressed.

I don’t have the training or proper equipment that could be used to do an analysis of the lamp in hand. I’ve tried with 30X and 100X hand held microscopes and couldn’t find anything obvious. 

That you’ve had a second bi-pin lamp fail in the same way is interesting. js explains that most if not all the failures represented here are envelope failures. I keep wanting to think there are other competitors that win the race to failure. I’ve found nothing to support my theory that extreme heat from the filament is destroying the fill gas.

Going on the likelihood it is an envelope failure I wonder if the following possible.

The high temperature of the package can sometimes translate into the standoff supports and into the pins then into the glass surrounding the pins causing some melting. That melting causes deformation and after cooling and contraction results in a path down the pins for the gas to escape. (a little like a lava tube) Then the next time the lamp is lit its fill gas is gone so the lamp overheats and begins to melt. The filament continues to release gaseous tungsten which, because of the compromised atmosphere, turns into blue-violet Tungsten Pentoxide and becomes a visible deposit on the inside of the glass envelope.


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## cutlerylover (Feb 21, 2007)

VERY interesting thread, and I got alot of information out of this, Thank you very much!


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## Icebreak (Feb 23, 2007)

Update:

Here is a superlative summary about many of the physics involved in lamp failures and explosions posted by js in his "The SF M6 X-LOLA: 200 lumens for 2.5 hours" thread.


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## Ctechlite (Feb 24, 2007)

I didnt' read thru all of this yet, but I see bulbs fail all of the time like the ones that are expanding in your photos in the first post. I work as a mechanic and replace dim bulbs all of the time that look like that. They still work but are very dim behind their plastic lenses.


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## LED61 (Feb 24, 2007)

I don´t know how in the world I missed this thread from the beginning. What a great amount of good info!! glad someone bumped it to the top!!


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## DNova (Feb 24, 2007)

I'd just like to point out that I am capable of doing a certain amount of failure analysis on incandescent light bulbs. I can anaylze the chemicals building up on the inside of the envelope. The presence of oxygen compounds obviously indicates envelope failure or bad gas mix (which is very unlikely with high quality lamps). I can also visually and chemically inspect the filament to see if it was a thin/hot spot that broke, or perhaps a break from too much physical force, or oxygen poisoning. Even the smallest filaments are big enough for me to easily analyze. If you'd like me to have a go at your bulb(s), let me know. 

I can't guarantee that I'll be able to reach a conclusion for any given lamp, but I have equipment at my disposal that opens up a lot of possibility for me to do so. I have only a little experience at failure analysis of lamps at this point, but I am learning more daily. Soon I'm going to have a large supply of burned out headlights to analyze. These halogen headlights are *overdriven* and have relatively short lifetimes. They are overdriven on purpose due to their use. I will hopefully be learning a great deal from this work. 

Also, if you want to SEE (with the naked eye) the stresses in your glass envelopes, you can easily do so with a couple small sheets of polarizing plastic. You could compare the stresses trapped in the glass between straight pin and bent pin lamps to see if there is that much difference.

PS - I love all the pictures in this thread!


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## js (Feb 24, 2007)

Icebreak,

As mentioned already by DNova, there is one possibility that would explain things besides envelope failure, and that is a bad fill gas mixture from the factory.

Almost all halogen lamps are evacuated from one end and filled from the other. I think the lamp is usually evacuated from the top and filled from the pinch, but it could be the other way around. Two companies that I know of (there are probably others) fill AND evacuate from one end: Welch Allyn and Carley Lamps. On lamps such as these, the top has no tip off, but is instead rounded and smooth. According to Osrams "Tungsten Halogen Low Voltage Photo Optics" paper, this is a VERY technically demanding process and very few lamps are made this way due to that.

So, I'm wondering if maybe at some point WA produced some lamps that didn't get fully evacuated before they were filled?

That's at least theoretically _possible_ if unlikely.

I would think that it would be always possible to see the place(s) where envelope failure occured in a lamp with an obviously contaminated interior atmosphere.

I am still of the opinion that if everything else is the way it should be that overdrive, even severe overdrive, will not in any way degrade the fill gas. For the most part it's a noble gas, which will in no way break down or react with anything else even at very high temperatures (that's what makes it a noble gas!). In fact, xenon is what is used in some of the HID lamps to form the arc, IIRC, and it doesn't break down or anything.

Still, overdrive is what it is, and it certainly doesn't HELP anything to push a lamp.

But, as I've mentioned before the Tiger11's and Tiger85's which use my ring-potted lamps are overdriven very hard--into the 11 hour filament life range--and out of more than 200 ring-potted lamps which I've put into the field, none of production versions (non field test ones) have exploded or had envelope failures that I know of. A number have insta-flashed or burnt out, but none have exploded or had envelope failures.

That's quite something and bears repeating, I think, because so, so many of the PR-base potted ones HAVE exploded/failed at the envelope. And also, it seems, quite a few bare lamps have done this. I'm guessing these were used with some kind of bi-pin socket? Like a Kiu socket or a MC slug or something? In those cases, one has to push the lamp into place and move it around a bit in order to get a good beam. This undoubtedly causes _some_ stresses on the envelope.

In any case, other than contaminated fill gas at the factory, I can't think of any other way to explain why my ring-potted lamps have experienced no explosions or envelope failures, but so many PR-base or bare ones have. Granted, there is the matter of simple numbers! 200+ ring-potted lamps vs., who knows?, 2,000+ PR-base or bare WA lamps? Maybe more? But still, given the anecdotal evidence I would expect to see some explosions or envelope failures with a sample size of 200+ ring-potted lamps.

For those who don't know what one of my ring-potted lamps looks like, here is a pic of some:







As you can see, the bottoms are surrounded by high quality ceramic potting material inside a stainless steel ring. My working theory is that this potting material strengthens the whole structure and prevents envelope failures when the pins are bent or pushed. Same goes for the one-piece lamp modules, such as the TL LA or SL-20X or SL-35X LA's.

Anyway, if DNova can look at those lamps in question to ascertain if there was any envelope failures, we can then move on to wonder,

1. was the fill gas bad from the factory?

and

2. if not, what happened and why? And why do the ring-potted lamps and one-piece reflector potted lamp modules not exhibit these failure modes? Or if they do, how come we haven't heard about it?

Could it simply be a matter of finger-oil or damage during shipment? From WA the lamps come completely surrounded by foam or bubble wrap so that they do not knock against each other or anything else hard. Yet, I have received some here from a CPF source that were sent to me all together loose in an envelope. Could that be an issue? The ones sent to me this way (10 of them) were all fine--or at least I haven't heard anything yet!

There is a lot to sort out here, but so far, I am still of the opinion that if everything else is as it should be that over-drive is a very small component of why lamps fail. Granted it certainly doesn't help and probably does hurt, but I suspect it doesn't add much to the failure rate all by itself. Obviously, this is just an educated guess at this point.

Just a teaser: it is my intention to try to put together a fairly complete thread on the subject of incandescent lamp physics. I hope to be able to get a tour of the Welch Allyn factory which is only about an hour North of me here in Upstate NY, and David Harchenko at Carley lamps has promised to send me some technical material on the lamp law equations, so the thread looks at this point to have some promise. Or at least the _idea_ does anyway! Right now I am still trying to track down some more complete and authoritative answer on exactly how CCT is measured and why there are such differences between the answers that Carley gets and those that Welch Allyn gets (compare life ratings of WA vs. Carley halogen lamps of the same CCT and you will see what I mean). I suspect that WA measures the temperature of the center coil only and that Carley gets some kind of weighted average--that's what David H. said to me anyway. But I haven't confirmed this with WA yet.


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## Icebreak (Feb 24, 2007)

DNova -

That would be terrific and much appreciated. Please PM me the address you want them sent to. I want to keep the big blue one for a while longer. I'll PM Fluffster and see if he can still mail his out for analysis. If not I'll go ahead send the blue-violet globe. I'll also include an unused Welch Alynn 01185 bi-pin for comparison.

I have a few others that may interest you. One of them had the filament melt and separate on both ends. It hurled up against the envelope and stuck. I've got one that melted the support pin. That must have taken some heat, probably not that rare. I've got another one I think you'll really like. This one shattered in half right down the fill port (pinch?). At first glance it appears that Tungsten Trioxide is present. However, when backlit, more colors appear possibly indicating other compounds formed on the glass first. Also a point appears where the gaseous tungsten seems to have began to transform because you can see a "shockwave" pattern.

You just never know who you are going to meet on CandlePowerForums. Glad you found us.

- Jeff


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## Icebreak (Feb 24, 2007)

Icebreak said:


> From this I’ll submit that all those purplish blue bulbs had an existing envelope failure. That failure could have occured for several reasons including a failure at the factory. The fill process at the factory may have failed.





js said:


> Icebreak,
> 
> As mentioned already by DNova, there is one possibility that would explain things besides envelope failure, and that is a bad fill gas mixture from the factory...snip
> 
> ...



Agreed that it's a possibility.

Thanks for checking back in.

I'm looking forward to your lamp physics thread.

- Jeff


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## DNova (Feb 24, 2007)

Icebreak said:


> DNova -
> 
> That would be terrific and much appreciated. Please PM me the address you want them sent to. I want to keep the big blue one for a while longer. I'll PM Fluffster and see if he can still mail his out for analysis. If not I'll go ahead send the blue-violet globe. I'll also include an unused Welch Alynn 01185 bi-pin for comparison.
> 
> ...


 I'll PM you as requested, but just so it's completely clear, my testing is necessarily destructive for these samples (I will have to break the bulbs, etc). If that's alright with you, this will be a very interesting project.


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## 65535 (Feb 24, 2007)

I hope you are careful at breaking the bulbs any touching of the filamen tor supports could cause anomallies and that could mess up data, food for thought, I think this is a great idea though.


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## DNova (Feb 24, 2007)

65535 said:


> I hope you are careful at breaking the bulbs any touching of the filamen tor supports could cause anomallies and that could mess up data, food for thought, I think this is a great idea though.


Heh, thanks for the tip. I assure you I'm fairly experienced in sample preparation methodologies for the analysis techniques on which I work for a living.


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## Icebreak (Feb 24, 2007)

Yes. It's absolutely clear that the analysis techniques will require the destruction of the samples.

Any images from your stereoscope or FE-SEM would be greatly appreciated. (It's understood that your work is not to be republished or captured without your expressed consent. I have no purpose for any images you may care to share other than in this thread to help advance our understanding of lamp failures.) The chemical analysis is a huge favor and already more than I could ask for.

Thanks for taking this on. Interesting indeed.

- Jeff


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## Icebreak (Feb 25, 2007)

Ctechlite –

I recall your reporting automotive lamp failures. Thank you for those reports.

I had thought automotive lamps would fail for three basic reasons, a power source surge, a physically traumatic event or the predicted end of life cycle. I’ve learned that there are many more causes of failure than these three.

One of the links in this thread is to a critical review by a metallurgist, Frederick G. Hochgraf, of a manual titled Lamp Examination for ON or OFF in Traffic Accidents. Analyzing automotive lamp failures and the critiquing of those analyses is important to the auto industry and associated organizational entities such as insurance, legal, judicial, consumer and law enforcement. It would follow that the analysis of ON or OFF lamp failures is important to most transportation industries.

An airliner crashed while landing locally a few years ago. The crew was given clearance but several warnings about a fast moving, powerful storm. One of the last things that happened during the crash was the airliner striking a landing light tower. I’m certain the ON or OFF state of these lamps was analyzed to help in determining the cause(s) of the accident.

When I saw the coverage I thought that if the airliner, going 90 mph, had not struck the light tower it would have ended up in the river.

There was some controversy about rescue going to the wrong end of the runway. This was likely due to terrible visibility and the fact that the crash began at the approach end and continued all the way down the runway to off of the other end of the runway. Interestingly, some of the survivors walked directly from the crash site to a hotel and checked themselves in. 

CNN report Radar image NTSB FAA

The above tangent was partially to make the point that I’ve discovered the study of lamp failures is being done by folks interested in more important things than why a modified flashlight fails. My interest was primarily to determine if the power sources were causing explosive and non-explosive failures and further; if noting the color and composition of the elements in the residue adhering to the inside of the envelope would tell us what really happened.


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## DNova (Feb 25, 2007)

Do you have the full text of Lamp Examination for ON or OFF in Traffic Accidents? If not I might be able to find it on Monday.


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## Icebreak (Feb 25, 2007)

I do not have the full text. I looked on line and found references and also where Northwestern would sell it for $20.00.

Here are more details about the manual:

Baker, J. Stannard, and Thomas Lindquist, Lamp Examination for ON or OFF in Traffic Accidents (PN 82), The Traffic Institute, Northwestern University, 1972


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## LED61 (Feb 26, 2007)

JS, Icebreak, and Dnova, I just want to thank you gentlemen for the scientific work and great insight/transfer of knowledge. I´ll follow this thread intently.


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## Ra (Feb 26, 2007)

js said:


> which traps the heat, insulting the lamp, thus pushing up the envelope temperature way past the sort of temperatures we would find even in our over-driven WA lamps. (Not because the FILAMENT is hotter, but because the temperature gradient from filament to wall is shallower).




What???  Do we have to insult our lamps now to get a better efficiency !!! :candle:

Great thread BTW..


Regards,


Ra.


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## Icebreak (Mar 11, 2007)

Here's a ROP reported by *LumenHound*. It's interesting that it has white residue on the enveloper indicating this fill gas was fine until the lamp exploded but the filament looks like it has some  Tungsten Pentoxide (W2O5) Blue-violet on it. This would be a previously compromised envelope that caused a failure as noted in LumenHound's description:

"I've had the solder blob on the bottom of the bulb soften and flatten out before.






This bulb blew because I hadn't enlarged the hole in the reflector I was using to the proper size. The bulb envelope became scored on the side from the too small reflector opening when I was spinning the flashlight head during focusing. I kept the head off the flashlight and ran this bulb inside a mason jar on the tool bench. 

The bulb lasted about a dozen 5 minute runs before it went. "


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## Ctechlite (Mar 11, 2007)

I think the point I was trying to make is that our flashlight sample is too small to think that the failure of "our" bulbs is abnormal. If the sample group were enlarged to include as many bulbs as there are in the vehicles on the road (truck/bus/car/air transport etc...) We maybe would find that these types of critical bulb failures were quite common. I know there are on/off failure studies, ie I've not seen an actual report but I was told by someone that some accident investigation agencies can determine if a brake light was illuminated at the time of impact (accident) or not by examining the bulbs.

Disclaimer : I am not a scientist, I do not proclaim to be one, or associated with any (although I do have a very good friend who works in a lab doing some kind of biological/chemical studies who is currently unemployed so if know of a job for him please let me know and I'll pass it along). My experience with formal scientific methodologies is limited to what I can vaguely recall from almost 15 years ago when last I stood in a chemistry lab. 

PS : If it would help you any I would be glad to start saving and cataloging (sp?) automotive bulbs and sending them on to you. The only thing I think I would not be able to provide was on time, as I cannot tell you how long it was in the vehicle. 

Anyway just trying to provide some helpful input.


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## DNova (Mar 11, 2007)

Determining if the bulb was on or not when it was impacted in a car crash would be fairly easy. That's a very interesting real-world application to the failure analysis I'm starting to learn. 

As far as sample set goes, I think you're right that we can't make any overarching conclusions based on a sample of 10 flashlight bulbs. We'd need a more formal and more comprehensive study to make really solid conclusions. But I don't have the money for that, so we'll do with what we have, and be careful about the conclusions we make. I'm about to get into bulb failure analysis pretty heavily, with all sorts of bulbs, and the goal starting out is to learn to identify bulb failures and see if a larger more formal study would be useful.


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## PhotonWrangler (Mar 11, 2007)

Interesting thread.

Many years ago I was up on a ladder, focusing an adjustable studio lighting fixture. This fixture had a large bi-pin halogen bulb with a ceramic base surrounding the pins at the bottom.

These fixtures were known for transmitting vibration from the focusing knob to the base of the lamp. I made my adjustment and then climbed down the ladder. MOments later the light turned orange, then bluish, then it exploded! I don't remember what color the glass shards were (I was more interested in the safety of the crew at the moment) but I can guarantee that the envelope of the lamp didn't have any fingerprints on it and the failure was most likely triggered by the vibration.

I'm guessing that one of two things probably happened - 
1) The filament developed a weak spot from the vibration.
2) The filament briefly touched the glass envelope from the vibration and weakened it.

The lamp wasn't being pushed beyond it's ratings and it was in an open fixture so there wasn't any more heat buildup than there should've been.


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## DNova (Mar 13, 2007)

I just made some beautiful tungsten trioxide crystals by burning an automotive hi-beam (I had already extracted the useful bits of the low-beam filament for analysis) in air at around 3.5VAC. I'm going to try to take some pictures but so far optical methods are not doing them justice. It was amazing to watch, too. It coated the glass in a neat swirled pattern. Oh god I love light bulbs.


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## DNova (Mar 13, 2007)

See pics here


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## Lunal_Tic (Apr 23, 2007)

:bump: for a great thread.

2 things, one thanks for everyone's efforts in this thread. It is a great read that is thankfully written in a manner that I understand (well most of it  )

Two, is it at all possible that the cleaning solutions, alcohol or whatever, that we use on the bulbs contributes to the envelope failures? On bi pin bulbs there would be only a residue but on potted bulbs it's possible that the liquid goes into the potting material under the bulb.

-LT


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## Icebreak (Apr 23, 2007)

I've thought about that too, LT. I think it's a possibility. I use 70% IPA like Don Klipstein, author of "The Great Internet Lightbulb Book" (link stickied in this forum) recommends. You know the idea is that the alcohol solves the oils and the water solves the salts. If I ever run across some close to pure ethanol I'll use it to get rid of the residue left by the IPA.

Well, I think that on the glass envelope there's no problem but if the IPA got into the ceramic potting it may not evaporate quickly and that could cause problems. The potting then may not have equal thermal absorption causing the part of the lamp envelope in the potting to have differing surface temperatures and fracturing. I think this is a very low possibility but still a possibility. The reason I think it's a low possibility is because the 70% alcohol helps the 30% water to evaporate.

I couldn't find the thread but I remember reading that one fellow didn't let the lamp and lamp holder dry after a vigorous cleaning with alcohol. During operation it was reported that the alcohol went phoomp. Wish I could find that thread.


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## Icebreak (Apr 24, 2007)

Adding another ROP that exploded. This one is Josey's. This one was powerful enough to embed glass into the aluminum reflector and remained embedded after the reflector was cleaned. Here is Josey's thread.


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## Icebreak (Aug 24, 2007)

Here's a new one. *mrmike's* ROP running on 6 sub C cells in a 5D. The potting got so hot it lost its adhesion and began to become particulate. He noticed the head was fogging up and found that the lamp holder on the switch had begun to melt. I don't know if this is a resistance problem causing things to heat up to much or if the destruction of the questionable potting caused the over heating. The lamp still works. I'd guess that it would be a good possibility that the glass envelope would win the race to failure here. Of course if we allowed the potting to be a participant in the race to failure it would have already won.

This came from mrmike's thread.


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## LuxLuthor (Aug 25, 2007)

Icebreak, not sure if these will be of any use. WA-1185 overdriven in hotdriver to 10.8 Vbulb and with about 12-13 hrs of use. It slowly faded out over about 10 seconds, then died. Note same blue and some white residue.

Other is one of Carley's 43W 14.8V that FiveMega had made and noted in this thread. It is still working, and has been run at least 15-16 hours on it, also in a Hotdriver with it set to 14.9 Vbulb. It has dark shading in two places inside bulb, but still performs well in FM3H-2. I tend to use this for 5-15 seconds at a time which may be why it is lasting longer than it's rated life.


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## Icebreak (Aug 26, 2007)

LuxLuthor -

I do think your lamps are interesting. The first thing that jumps out is that both are showing the thermal convection currents of the fill gas. The one on the left is like a freeze frame showing when and where the aerosol of violet-blue tungsten pentoxide (formed from the reaction of the boiling tungsten with the foreign air in the compromised fill gas) deposited on the envelope. The one on the right is like a freeze frame showing where some evaporated tungsten condensed on the envelope. 

I'm sure you know that the Fivemega custom Carley 43W is not at all a lamp failure. Of some interest is that there is a failure evident but I believe it was a planned failure. I’m guessing that since the lamp was a custom lamp it may have had a custom fill specification by Fivemega. Maybe a little less halogen (probably bromine) was used. So the chemical transport reaction is not happening 100% of the time. In other words, not all of the evaporated tungsten molecules are bonding with the halogen to form a tungsten oxyhalide (tungsten(VI) dioxydibromide or WO2Br2) so, following the convection currents of the fill gas, they condense on the walls of the glass envelope resulting in a little blackening.

I said planned failure because less halogen allows for higher pressure according to js.

_"In fact, the SureFire high-pressure xenon lamps intentionally reduce the halogen compents of the fill gas in order to be able to get a higher pressure. This results in a more efficient lamp, but one which still does not blacken as fast as a straight xenon or krypton fill lamp with NO halogen compent." - js _

So what it seems is that you have an extremely well designed lamp that has been driven at a level that was optimal. It’s showing some darkening but it has lived beyond its life expectancy. I’ll bet it has been a great performer for you. The photo tells a story. Thanks for posting about it.


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## LuxLuthor (Aug 26, 2007)

I have to say FiveMega's Carley bulb is really a spectacular choice for those who do not have a Hotdriver to deliver regulated voltage. I had noticed the blackening start about 5 hours ago, and it does not seem to have progressed, but I will remember to take a followup if any changes or failure occurs.

When I asked FiveMega for more details about this, it was not my impression that he knew about the level of precision in design in terms of gasses. His PM's to me conveyed more of a design request for a 4s Li-Ion voltage, low amp (to avoid Li-Ion PTC cutoffs), high bulb lumen bipin, and ended up with this. He didn't have more specific details to give me other than (CL 43 watt (14.8 volt, 2.9A, 10 Hrs life) 1450 bulb lumens).

Also, I make sure to always clean my bulbs once with 100% lab grade methanol, apply Pro-Gold _(now called Deoxit Gold)_ then again clean the exposed bulb once in bulb holder with 70% isopropyl.


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## Bullzeyebill (Aug 26, 2007)

Why Pro-Gold which has a mild lubricant? 70% isopropyl is not the best degreaser out there. I use Pro-Gold as an electrical contact cleaner/enhancer after some Detroit cleaning, (my Pro-Gold is still labeled Pro-Gold). Maybe I am wrong, but Pro-Gold on a glass envelope?

Bill


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## LuxLuthor (Aug 27, 2007)

I assumed everyone would realize I meant only applying Pro-Gold to the bipin legs. I realize that about Isopropyl, which is why I use the 100% methanol as the first cleaning step. This combo works great, as I have never had any of my hundreds of bipin bulbs fail from anything other than overdriving, or testing voltage flash level.


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## Bullzeyebill (Aug 27, 2007)

Thanks for clarification. Yes, on the legs, good idea. I have the needle injector setup for Pro-Gold. That stuff lasts forever. I have spilled more than I have used.

Bill


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## LED61 (Jan 2, 2008)

There´s been some lamp failures lately, so I thought it would be a good idea to bump this wealth of information by JS and Icebreak to the top again. Those that have had lamp failures lately will find the information very useful.


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## Icebreak (Jan 10, 2008)

I believe this is the one you were talking about from MitsosOsougias's thread

What a beautiful failure. I'd like to know what that odd brown spot is.

Tungsten Pentoxide (W2O5) Blue-violet would indicate a fill gas failure before this lamp was energized. That would mean there was an envelope failure. As many of us have noted, this could be from the factory that way or it could have QA issues that made it prone to do this after a few uses or it could be that it experienced a shock that failed the envelope. Because this lamp had seen useful operation it's unlikely that it came from the factory with a fill gas problem. Because the torch was an M3 it is somewhat unlikely that it experience a physical shock before being energized. It's more likely that one component of the lamp such as but not limited to the envelope, the pins' pressure on the envelop or the potting did not have 100% integrity. During one use this caused a tiny structural failure in the envelope unnoticed by the user. This allowed the fill gas to be compromised. When the lamp was energized on the last use, the second cascade failure took place resulting in this colorful lamp failure.

I'm guessing that a call to Surefire is going get the owner a new lamp for his M3.

MN-10 I think.


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## Icebreak (Jan 10, 2008)

My apologies to member allthumbs. I've had his lamp setting on my scanner for months. The bent flanges are due to the 300 lb gorilla robot that works at the postal service.

This is another melted solder blob that caused the lamp holder to become very hot. I think we are getting somewhere with identifying the cause. After straightening the flanges out I installed this lamp in an excellent 5C ROP torch powered by 6 Elite 4500mAh sub C cells. allthumbs let me know that his torch was a purple 2C ROP-LE. In the 5C sub C ROP with the head off the following observations were made while wearing safety glasses. After one minute the lamp was working quite nicely. After 2 minutes a slender waft of smoke was seen. After 3 minutes the unit was obviously smoking. I turned the lflashlight off. After 4 minutes the lamp holder was much hotter than it should have been.

I removed the lamp. Looking at the bad lamp I could see the solder anode connection had deformed a little more. Looking into the lamp holder dark brown swirl patterns were apparent showing were the smoking occurred. The plastic parts of the holder were unaffected. So this would indicate that it was the only the solder blob experiencing destruction. It's possible that if an autopsy were done we may see that the potting material began to become particulate. If a Dremmel tool is in my future I'll do an autopsy and post what I find.

My best conclusion is that resistance was not a problem. I believe that the potting material did not have 100% integrity from the factory. In other words the mix might not be quite right in some areas of the potting or there might even be a pocket of air in the potting. This would explain the exceedingly high temperature during operation causing the solder blob to melt. I'd like to submit a speculation that the smoke might be from flux in the solder turning into a gas.

I believe from this test that some Pelican 3854-H lamps may have limited QA problems with the potting probably not causing failiure in the lanterns they are designed for but failing in some of our HotWires because we are pushing them to higher levels of efficacy.


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## WildChild (Jan 10, 2008)

When I built my ROP, fogging appeared on the reflector after 2-3 minutes and woudn't disappear after. I had to clean the reflector! I did not check if the solder blob of my bulb was melted at this time but when I looked at it after 2-3 complete battery runs it was melted... I reformed it, and a 5 minutes run wasn't enough to melt it again. I don't know yet if it will happen another time. On my ROP, the socket deformed slightly and became textured but no malfunction. Again I don't know if a melting will happen again.



Icebreak said:


> My apologies to member allthumbs. I've had his lamp setting on my scanner for months. The bent flanges are due to the 300 lb gorilla robot that works at the postal service.
> 
> This is another melted solder blob that caused the lamp holder to become very hot. I think we are getting somewhere with identifying the cause. After straightening the flanges out I installed this lamp in an excellent 5C ROP torch powered by 6 Elite 4500mAh sub C cells. allthumbs let me know that his torch was a purple 2C ROP-LE. In the 5C sub C ROP with the head off the following observations were made while wearing safety glasses. After one minute the lamp was working quite nicely. After 2 minutes a slender waft of smoke was seen. After 3 minutes the unit was obviously smoking. I turned the lflashlight off. After 4 minutes the lamp holder was much hotter than it should have been.
> 
> ...


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## Icebreak (Jan 10, 2008)

Hmmm. It would seem that a five minute run would have melted it if it were going to melt. I wonder if the quality of the factory solder blob could be a factor. That never occurred to me. Interesting.

Thanks for checking in, WildChild.


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## WildChild (Jan 11, 2008)

Icebreak said:


> Hmmm. It would seem that a five minute run would have melted it if it were going to melt. I wonder if the quality of the factory solder blob could be a factor. That never occurred to me. Interesting.
> 
> Thanks for checking in, WildChild.



When I reformed the solder blob, no fumes came out. Maybe there was still flux mixed with the solder, making it less heat resistant and this is what caused the fogging of the reflector when it melted the 1st time?


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## Icebreak (Jan 11, 2008)

Yes, that sounds totally viable. And then the resistance would be higher causing more heat, as the blob melts and reshapes the lamp's physical contact points become altered causing the thermal path to go wonkers (scientific term, apologies) into the sides of the PR base finally heating up the plastic part of the lamp holder causing it to melt and carbonize (textured, like you mentioned, is a better, more graphic term).

Wow. Good one, WildChild. I would have never thought of that.


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## jugg2 (Jan 11, 2008)

Am I looking at the pics wrong, or are the glass envelopes actually deforming without exploding? Some look like they have become hot enough to change shape.


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## Icebreak (Jan 11, 2008)

Your observation is correct. If the fill gas escapes before the lamp is energized the filament is existing in a compromised atmosphere. The gradient temperature between the filament and the envelope changes drastically. The envelope can become so hot that it glows red/orange and it begins to become a liquid. The pressure in this compromised, heated atmosphere can cause the now soft envelope to balloon and reshape. It's a little like the process for blowing glass with one large exception that the source of heat is internal not external.


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## rhuck60 (Jan 11, 2008)

My thoughts on this issue primarily revolve around the quality of solder itself. 
I know from experience that the quality of solder varies considerably. 

If as I suspect Pelican used a very cheap solder (almost pure lead, and no tin) then the melting point would be very low and with high electrical resistance.

I believe that if any member planning or running a ROP-HI mod would remove the solder from a new bulb and replace it with a quality solder these issues with the Pelican bulbs will almost entirely disappear.


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## Alan B (Jan 11, 2008)

The trend with solder is to move away from lead, perhaps this is a lead-free solder problem? Those are quite common.

-- Alan


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## WildChild (Mar 10, 2008)

rhuck60 said:


> My thoughts on this issue primarily revolve around the quality of solder itself.
> I know from experience that the quality of solder varies considerably.
> 
> If as I suspect Pelican used a very cheap solder (almost pure lead, and no tin) then the melting point would be very low and with high electrical resistance.
> ...



Once the solder blob melted on both bulbs I used, I reformed the solder blob and it never deformed again! My first bulb died after a drop, this second bulb is still up and running!  I posted in another thread that the positive nipple on the ROP-HI bulb is dull next to the ROP-LO bulb that has a shiny nipple. After reforming it when it melted, it became shiny. I had no melting problem with the ROP-LO bulb I tried.

[EDIT]I was wrong, I just noticed a solder blob I reformed melted again... I'll use up my current stock of ROP bulbs and I'll switch to ROP-LO and bi-pin after.[/EDIT]


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## Icebreak (May 12, 2008)

For statistical purposes, fuzzy as they may be here, Paladin has reported a P91 explosion using 2 series 18650s. Here's his thread. 

The envelope fragmented into coffee grind sized particles.


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## LuxLuthor (May 12, 2008)

I just noticed this thread today, and with all the destructive testing of various bulbs that I have done, now find it quite remarkable that only 2 bulbs show any visible discoloration which are in center, with 3 views of those bulbs shown amidst this sample of bulbs pushed to failure. None of any bulbs I have tested have exploded. (thumbs)


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## Icebreak (May 12, 2008)

Thanks for another timely contribution, LuxLuthor.

This gives us some things to contemplate. Like how your tests play into failure stats reported on CPF. It could be that the spectacular failures are more likely to be reported. It could be that the human factor is playing more of a role than would first seem evident. Vibration shock, bending, shaking, dropping etc. Thanks again for the report, especially those nice photos.

Excellent work on your Destructive Bulb Testing thread, BTW. From what I've gathered from _js_, your testing is not dissimilar to the methods lamp engineers use to verify base measurements before publishing ratings. One striking difference is that in your tests I know the guy doing it and exactly how he's doing it.


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## js (May 12, 2008)

Icebreak,

Indeed. We know, for example, that LuxLuthor is careful and methodical and certainly didn't leave finger-oil on the envelope. We also know that he didn't over-stress the lamp leads and compromise the structural integrity of the glass envelopes.

And, this perhaps explains why *none* of the bulbs he tested has exploded.

This, I think, is more evidence in favor of the interpretation(s) I have been proposing in this thread.

LuxLuthor,

Just FYI: you posted to this thread several times already (see above).


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## LuxLuthor (May 12, 2008)

js said:


> Icebreak,
> 
> Indeed. We know, for example, that LuxLuthor is careful and methodical and certainly didn't leave finger-oil on the envelope. We also know that he didn't over-stress the lamp leads and compromise the structural integrity of the glass envelopes.
> 
> ...



What I meant to say is I have not seen (or remembered about) this thread since I started doing the destructive bulb testing, and accumulated such a "hallowed graveyard" of bulbs.


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## BVH (May 12, 2008)

May those mighty little beacons of light who so willingly gave their lives in the interest of furthering the knowledge base of those here on CPF, be martyred forever in the annals of time. Or at least for 6 months. Lux, i hope you consider a proper burial for those little shining stars who so willingly gave their Lumens - and them some!


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## Icebreak (May 12, 2008)

js said:


> This, I think, is more evidence in favor of the interpretation(s) I have been proposing in this thread.



That's what I initially came away with as well and that's a valid view. However, upon further contemplation, LuxLuther's tests are ramp-ups. The lamps aren't being slammed with spike and surge like they would be under real world operation in a flashlight. I think that is what stresses lamp systems more than operational overdrive current and operational thermal energy. Successful overdrive does stress the systems but we can't see to what level components are compromised until they fail.


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## jerry i h (May 13, 2008)

js said:


> Icebreak,
> 
> ...LuxLuthor is careful and methodical and certainly didn't leave finger-oil on the envelope. We also know that he didn't over-stress the lamp leads and compromise the structural integrity of the glass envelopes.
> 
> And, this perhaps explains why *none* of the bulbs he tested has exploded...


Hmmm....sounds like you are close to figuring out this conundrum. If you can solve this riddle, even I would do a bi-pin hotwire. 
Example: I have a cheapie desk lamp that I have had for 5 or 6 years. It is a 12v 10w bipin G4 halogen. It is on several hours day-in and day-out, and has a lifespan of, say 2 years, as I am on only my second bulb. Yet, you folks put it into a hotwire flashlight, and  after only a couple of hours? BTW, when I replace the G4, I just open the package and stick it into the lamp with my bare hands.


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## DM51 (May 13, 2008)

That's because your bulb is not being over-driven. Its life is probably ~2,000 hours if driven to spec. If you threw a higher voltage at it, it would be a lot brighter and its lifespan would be dramatically shorter.


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## js (May 13, 2008)

LuxLuthor said:


> What I meant to say is I have not seen (or remembered about) this thread since I started doing the destructive bulb testing, and accumulated such a "hallowed graveyard" of bulbs.



Got it! I figured maybe that's what you meant, but I just wanted to mention your previous posts (as they are good ones) in case you'd forgotten them. That's all.


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## Icebreak (May 27, 2008)

Bimmerboy's failed lamp.







Bimmerboy's thread about this failure.


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## LuxLuthor (Jun 21, 2008)

Icebreak, I thought of your thread when I replaced this 60W globe decorative bulb. I noticed the cracks were on top (it was screwed in perpendicular to bathroom wall above mirror, and was positioned with cracks on top in socket. I don't which came first the crack or the failure....but certainly this bulb had a nice long life. You can see the blue on the failed filaments in closeups.


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## Icebreak (Jun 22, 2008)

That is too cool! It looks like some kind of chaotic art.

I clicked on the pics and studied them in expanded mode. Really quite interesting.

Thanks for bringing this.


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## LuxLuthor (Jun 22, 2008)

LOL...I know....I kind of hate to even throw it away. Very few people would appreciate the obsession.


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## DM51 (Jun 22, 2008)

It's a very interesting effect. A pic of it against a white background might make a good avatar.


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## RODALCO (Jun 23, 2008)

Cool thread,

I see if I can find my failed 300 or 500 Watt tubular halogen lamp at work, which failed after been mounted under a 45° angle, at a local substation as security light.

The filament melted through the glass and failed afterwards.

Regards, Raymond


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## lctorana (Jun 24, 2008)

RODALCO said:


> ...failed after been mounted under a 45° angle...
> 
> The filament melted through the glass and failed afterwards.


 
Very interesting.

This is obviously why bulbs (and valves with >10W filaments) have mounting recommendations.

For example, the RCA Electron Tube handbook recommends for some power valves:

"_Vertical mounting is preferred, but horizontal mounting is permissible if pins 2 and 7 are in the vertical plane_" or whatever.

Interesting to read an example of what happened when a bulb was mounted not according to manufacturer's preference.

I would have loved to see a filament melted through the glass.

Projector bulbs with a big bulge right next to the filament, I've seen, but never that.


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## Icebreak (Aug 9, 2008)

Just a simple instaflash here. The HPR50 by Radio Shack is somewhat interesting in that in runs a really nice color when regulated at spec. This one I bought but I've also seen this lamp in a regulated, rechargeable incan I have. I can't remember the name of it and there is no labeling. Looks like something a Clingon might carry. Has a blue LED back lit LCD battery readout. So, because RS has an HP50, I think this HP*R*50 was made for rechargeable flashlights. It failed while fiddling aroundwith a Vintage Mod.


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## RODALCO (Aug 23, 2008)

I found the failed bulb and took a couple of photo's.
It was rated at 500 Watts 240 Volts.



​​


​​


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## RODALCO (Aug 23, 2008)

Full view of failed quartz tube.


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## Icebreak (Aug 23, 2008)

RADALCO -

That is a very interesting group of failures in your lamp. I've never heard of such a thing and now we can see it. Amazing. It looks like the lamp envelope failed with a bubble, then the bubble ruptured causing an atmosphere failure, the filament overheated and bent, then the filament melted into the glass. Maybe the glass was red hot and pliable which helped the hot filament survive, for a while anyway, an intrusion into the glass.

Fanstastic! Thank you very much for the time and effort in photographing, hosting and posting this.


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## zipplet (Aug 24, 2008)

I think the bubble in the middle is normal in this type of lamp? Either way, this failure is quite surprising and unique!


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## RODALCO (Aug 24, 2008)

The bubble in the middle is normal for this type of lamp, *zipplet.*
That is from where the vacuum is created.
Regards, Raymond


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## Icebreak (Aug 24, 2008)

My lack of observational skills startles me sometimes. I have two of those lamps in work lights that I use all the time. I just went and looked and the gas fill/vacuum orifice is right there in the middle.


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## LuxLuthor (Aug 27, 2008)

This is my attempt to make lemonade out of my stupidity by capturing these bulb shots. I was too excited to use Fivemega's 3 x 16760 (AW protected Li-Ion) to power 1185 in FM's bulb holder for SF-M6. There was an initial nice bright flash as I began tightening the tailcap, followed by an increasingly yellow==>orange sickly output until dead.

The Li-Ion's were charged last night on Pila charger and had 4.17V each (pack 12.52V). Ending 4.15V (pack 12.46V). I put the approximate run time on these 4 pix (thumbnails).


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## Patriot (Aug 28, 2008)

That round bulb with the blue streaks is sweet Lux...lol :laughing:


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## DNova (Aug 29, 2008)

Icebreak said:


> RADALCO -
> 
> That is a very interesting group of failures in your lamp. I've never heard of such a thing and now we can see it. Amazing. It looks like the lamp envelope failed with a bubble, then the bubble ruptured causing an atmosphere failure, the filament overheated and bent, then the filament melted into the glass. Maybe the glass was red hot and pliable which helped the hot filament survive, for a while anyway, an intrusion into the glass.
> 
> Fanstastic! Thank you very much for the time and effort in photographing, hosting and posting this.


 
In my opinion one of the round molybdenum filament supports popped out of place, maybe due to the odd mounting arrangement of the fixture. 

The hot, still operating filament managed to melt itself into the quartz envelope where it eventually broke. It appears that part of the filament embedded in the quartz is still quite shiny and nice, while the rest has a dirty-looking coating of oxide. It didn't operate for very long at all after the envelope was compromised. I'd guess that by the time atmosphere was allowed in, the filament was already cooling down. 

Hey there, by the way


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## Icebreak (Sep 1, 2008)

LuxLuthor -

You've solved a mystery and created a question. Remember this?

"When a lamp envelope is broken while the filament is ON, or the filament is energized subsequent to the envelope having been broken, the compounds which form and their colors are:

Tungsten Nitride, (WN2), Brown
Tungsten Dioxide, (WO2), Brown
Tungsten Pentoxide, (W2O5), Blue-violet
Tungsten Trioxide, (WO3), Yellow

* When a lamp envelope is broken while the filament is on, even briefly, you get yellow Tungsten Trioxide.

When a lamp envelope has failed previously to the filament being energized you get blue-violet Tungsten Pentoxide.*"
* 
*I've wondered what was going on with the lamps that have both blue-violet and white-yellow. Which formed first? Your posting this time-lapsed group of photos clearly shows that the blue-violet forms last. So I'm now thinking that all the multi-colored residue failures are after start-up and the blue-violet is indicating the eventual total failure of the atmosphere. It also seems to reveal that in Bimmerboy's lamp failure emulating a face, that the "eyes" were formed last.

It could be that the lamps that are totally violet-blue are the only ones where the fill gas failure took place before start up. But now I don't know because it appears that the tungsten pentoxide can overwrite tungsten trioxide. I think I need to take a closer look at those. The one lamp that for sure looks like a fill gas failure before start up is your Chaotic Art lamp.

Remember this?

"Ammonium Paratungstate (APT) [(NH4)10W12O41 . 5 H2O]


"

I had thought and still think it's possible that something like this compound might explain the pure white residue that has no yellow or chartreuse it. I'm also wondering if the pure white also seen in your photos might be residue formed when gaseous halides condense on the inside of the envelope. Looks like I've got a little more research to do.

For a lot of these failures I'm leaning toward spike and surge from our battery power sources stressing, fatiguing, compromising or otherwise destructively impacting the envelopes. I've yet to see a blue, white or yellow lamp that came from a regulated flashlight or from your destructive incan bulb tests. I'm not saying it couldn't happen. An atmosphere failure is an atmosphere failure. It just seems to be less likely while using a controlled current.

I want to thank you again for your contributions to this thread. Many people benefit from all of your contributions to the knowledge base of CPF.


*

*


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## LuxLuthor (Sep 1, 2008)

Thanks for your note! I still have this bulb, and I remember looking at it during the development but is not quite captured in the pictures. It started out in first shot as pure white, next two shots did have a slight yellow/brown hint when I viewed up close. Before the final shot, there was less blue, and over the next 5 seconds of turning it on, developed the final darker blue you see in last pix. Up close there is also a slight band of slight brown below the blue. I took these pix under a magnifying loop with different side incan lighting if they are further useful.


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## Icebreak (Dec 11, 2008)

This is ^^^ Nova's ^^^ EO-9 lamp from this thread. It impacted a concrete floor, continued running briefly, then popped. White residue indicates an envelope failure during operation which was exactly what was reported. Nice photos, I think.


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## Chrontius (Dec 31, 2008)

Just caught a race to failure event in my favorite X80 lamp tonight; I suspect it started last night and I assumed yellow hotspot -> dead battery. I got some good macro shots of the lamp, plus beamshots next to a stock A2 Aviator - due to regulation, this is an excellent benchmark light for such comparisons as the color temperature should be extremely consistent. I'll try to get them posted by this weekend.

I'm annoyed, though - this was my favorite perfect round hotspot, and I don't have a spare.


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## LuxLuthor (Sep 26, 2010)

Seems like we need some more failures before 2 years go by since the last one.


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## Icebreak (Sep 26, 2010)

2 YEARS! 

Gemini Crickets time goes by quickly.

My apologies for not maintaining this very well. Part of my lack of activity is that because of your work and the other 100 or so guys that really get into this have figured out so many combinations that work so well, along with the regulators that a few have been built, I don't see nearly the number of failures anymore.

Part of it is interests in other areas.

Part of it is budget.

There are some things I'd like to try but the dollars aren't there for experimentation. That's where I see most failures. We've kinda got it figured out for now anyway. But the advancement of the understanding of lamps and what they can or cannot do does still remain close to me as can be evidenced by my heavy usage. Don't have some of the crazy powerful lights that you and others have but I still use 1185s and others nightly and daily.

I stole one of yours you so kindly posted in the incandescent photo thread. I think it might make a fine "bump pic", no?






I'd sure like to visit your part of the world someday, Lux. I'd like to thank you in person for all your hard work. Slightly off topic. I really enjoyed your bean photo. 

I'll go over there and say so.


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