# UCL + 1185 = crack!



## ElectronGuru (Jul 4, 2009)

I keep reading that UCLs are fine for even high(er) power incans, so I've been trying it. About 20 continuous minutes into a run a Mag 3C with an 1185 bulb (FM holder) and UCL lens, the lens cracked. This was indoors in the tailstand configuration, so there was no rapid temp change and no shock involved. The glass is intact and even smooth to the touch:


----------



## Nos (Jul 4, 2009)

I guess thats why all high power incans have borofloat lenses...... but this is 1st time i actualle saw a broken ucl lens :green:


----------



## Illum (Jul 4, 2009)

often it does not have to rely on high temperature change to crack it, instead it may have arisen from a temperature difference too great for the glass to bear as the internal temperature rises beyond ambient.

I've done the same before, only mine cracked when I blew on the glass after operation. Its been Borosilicate windows for me since


----------



## LuxLuthor (Jul 4, 2009)

Illum said:


> often it does not have to rely on high temperature change to crack it, instead it may have arisen from a temperature difference too great for the glass to bear as the internal temperature rises beyond ambient.
> 
> I've done the same before, only mine cracked when I blew on the glass after operation. Its been Borosilicate windows for me since



When I looked closely at the pros/cons of UCL vs. Boro, I never saw the benefit of UCL in hotwires. Supposedly it has slightly higher light transmissivity, but on a practical basis I would always rather have heat durability.


----------



## lctorana (Jul 4, 2009)

Snap.

I have repeatedly recommended the use of a magnifying glass lens, but on my 2nd Mag85, I have an identical result.

RoP is the maximum for non-Borofloat, it seems.


Edit: Just thought of something else. It is possible that the UCL stands up well to radiant heat from thr bulb OK, but not to the demands of transmitted heat from a well heat-sunk head. Just a thought.


----------



## Patriot (Jul 4, 2009)

The transmissive advantage of the UCL is only 5-6% up from the borofloat so for me the small improvement isn't worth the headache. Like *Lux* stated, the difference in practical terms isn't perceivable to the eye, so even if you only run your mag85 for 2 minutes at a time it doesn't gain you anything and will still eventually crack.

I've been able to survive a UCL on an 1111 as part of an ongoing experiment but I've cracked a lens on an 1185 in nearly the same fashion that you did. In one intentional abuse test I had a brand new UCL last a mere two minutes on a 623.  I knew it wouldn't last, I just didn't know how quickly it would fail. UCLs are the perfect window for LED's but I mainly leave incans to the borofloats. Using a fatter o-ring between the bezel and the lens on a mag light tends to make the a UCL last a bit longer. I guess that's because it allows for more freedom to expand and contract??? In any case it prolongs the life but still doesn't save UCLs from ultimate demise.


----------



## Illum (Jul 4, 2009)

lctorana said:


> I have repeatedly recommended the use of a magnifying glass lens



oo:
found any that's a direct drop-in for a mag head?


----------



## socom1970 (Jul 8, 2009)

Might this happen to the SF 6P/9P tempered-glass bezel window while using the LF IMR-9 LA with 2 IMR 18650's?

I've used the P91+AW 18650's with no problems. Anyone know?


----------



## Aircraft800 (Jul 8, 2009)

I had the same thing happen with a WA1111 and a multi-LED setup. A metal reflector against a UCL glass lens, possibly screwed down too tight, against an aluminum bezel, with thermal expansion, many possibilities.


----------



## carbine15 (Jul 8, 2009)

Aircraft800 said:


> possibly screwed down too tight


+1 done that!
Torque kills glass lenses.


----------



## Patriot (Jul 8, 2009)

Using a fatter o-ring will help to prevent that.


----------



## Bullzeyebill (Jul 8, 2009)

Listen to the experts. Use Borofloat/Pyrex for high output incans. 

Bill


----------



## ElectronGuru (Jul 9, 2009)

socom1970 said:


> Might this happen to the SF 6P/9P tempered-glass bezel window



Aluminum SF incans come standard with Pyrex windows. I've read some things saying they are different brand names for the same thing and others saying that borofloat is better. In any case, I've found no evidence of pyrex ever shattering.


----------



## Bullzeyebill (Jul 9, 2009)

Borofloat and Pyrex are of the same chemical composition, but differer. See this link, http://www.flashlightlens.com/str/index.php?app=ccp0&ns=prodshow&ref=boro_lens

Bill


----------



## Justin Case (Jul 9, 2009)

Apparently, consumer Pyrex in the US isn't really Pyrex anymore, other than in name. But there is still some real two-phase, borosilicate Pyrex products out there (e.g., lab glassware). I would assume that SureFire's Pyrex windows are not the consumer grade, kitchen glassware from World Kitchens.

Float glass is just flat glass made by floating the molten glass on molten tin. Pilkington developed the original process. The trick is introducing the molten glass into the molten tin in a controlled fashion to avoid ripples and other surface disturbances so that the glass can solidify with two completely smooth, flat faces and with uniform thickness.

Flat glass used to be made by blowing glass and then flattening it, casting it on a flat iron surface, or rolling it between metal rollers. None of these methods produced the quality of flat glass that the float process does.


----------



## Illum (Jul 9, 2009)

Justin Case said:


> Apparently, consumer Pyrex in the US isn't really Pyrex anymore, other than in name.



this was bound to happen, immediately after Pyrex [glass chemistry] became Pyrex™ or Pyrex® and people gets deceived when profit-motivated companies market conventional glass under the name rather than the chemistry:shakehead


----------



## Bullzeyebill (Jul 10, 2009)

Illum said:


> this was bound to happen, immediately after Pyrex [glass chemistry] became Pyrex™ or Pyrex® and people gets deceived when profit-motivated companies market conventional glass under the name rather than the chemistry:shakehead



Guess I am missing something here. SF uses Pyrex trademark glass, and it appears to be optical grade, maybe the same as Borofloat. Where is the deception?

Bill


----------



## Illum (Jul 10, 2009)

Bullzeyebill said:


> Guess I am missing something here. SF uses Pyrex trademark glass, and it appears to be optical grade, maybe the same as Borofloat. Where is the deception?
> 
> Bill




Well, I wasn't referring directly to lights 
I've had the opportunity to buy cheap cookware measuring glasses that were advertised as pyrex glass but cracked open when I washed it out with hot water after measuring crushed ice cubes for homemade ice cream.:shakehead
on the other hand...
I've ran my surefire incandescent that had pyrex windows for the duration of its cells then promptly dumped it in a bucket of ice water... other than the reflector fogging up there were no known issues with the glass, my E2e still functions like new today


----------



## socom1970 (Jul 10, 2009)

Illum said:


> I've ran my surefire incandescent that had pyrex windows for the duration of its cells then promptly dumped it in a bucket of ice water... other than the reflector fogging up there were no known issues with the glass, my E2e still functions like new today



I've done that (well, cooled under a running garden hose, anyway) with my 9P+P91 with no problems at all. No cracked window, no fogging, nothing.

I've also done that with my L4 with no problems. 

(Funny, I've heard that's how the Glock pistols are cooled by the testers for the Glock corporation. After enough rounds are put successively through the Glocks to make them too hot to handle, they are dumped in a water bucket, then the tests continue. No wonder I like my Glock so much!:thumbsup: )


----------



## Bullzeyebill (Jul 10, 2009)

socom1970 said:


> I've done that (well, cooled under a running garden hose, anyway) with my 9P+P91 with no problems at all. No cracked window, no fogging, nothing.
> 
> I've also done that with my L4 with no problems.
> 
> (Funny, I've heard that's how the Glock pistols are cooled by the testers for the Glock corporation. After enough rounds are put successively through the Glocks to make them too hot to handle, they are dumped in a water bucket, then the tests continue. No wonder I like my Glock so much!:thumbsup: )



LOL. Makes me wish I had not sold my Glock years ago. They are truly a hardy weapon.

Bill


----------



## Patriot (Jul 10, 2009)

Illum said:


> I've ran my surefire incandescent that had pyrex windows for the duration of its cells then promptly dumped it in a bucket of ice water... other than the reflector fogging up there were no known issues with the glass, my E2e still functions like new today





I love it Illum.....lol. Keep up the brutal military testing...:thumbsup:





*Socom1970
*(Funny, I've heard that's how the Glock pistols are cooled by the testers for the Glock corporation. After enough rounds are put successively through the Glocks to make them too hot to handle, they are dumped in a water bucket, then the tests continue. No wonder I like my Glock so much!:thumbsup: ) 



They are one heck of a nice working machine aren't they! It was funny to run across your comment since I was just taking pics of one not 5 minutes ago. I've been experimenting with one-off threaded comps on a 10mm. It's based on the KKM design but these have non-generic port dimensions based on what I've learn from years of shooting open class pistols.


----------



## Justin Case (Jul 11, 2009)

Comps are great until you shoot in close quarters, unconventional positions and get sprayed in the face with crud.


----------



## GarageBoy (Jul 13, 2009)

Is Pyrex (houseware) still made by corning?


----------



## Patriot (Jul 13, 2009)

GarageBoy said:


> Is Pyrex (houseware) still made by corning?




That seems to be the case:

http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_guid/glass/pyrex.aspx


----------



## Justin Case (Jul 13, 2009)

That link confirms that Corning makes *lab* glassware in borosilicate Pyrex. World Kitchens provides the non-boro Pyrex consumer stuff.


----------



## Patriot (Jul 17, 2009)

Update to FM11 with UCL. I was walking with it last night and it heat cracked. I must say it lasted a long time. I'm guessing the 100 degree ambient temperature had something to do with it.


----------

