# Gasoline de doming 100% working method?



## Tatjanamagic (May 4, 2013)

After I ruined few emitters with razor, and heat I wanted to try "100%" successful method as claimed by few members on "other forum". Just soak it and wait dome will fall off they said. So here we go...



*GASOLINE DE DOMING*

Did I succeed? 


Well this is non working XRE-EZ900 in a ruined pill... I just soaked first half of pill in gasoline overnight and I got this:







Dome fell off and all phosphor is still at its place so can I tell this was successful or not? Looks good to me...






*I was happy with gasoline method results so I decided to de dome still working pill with an XML led...*

Same procedure of soaking half pill in gasoline but this time I went to check how it is doing, and after 4 hours dome fell off but it seems that dome took phosphor layer of emitter... 

Maybe I am guilty for that because I left gasoline outside, and it was very warm day?

I was angry but pill is still working... Damaged but throws further than ever... 40 000 lux of improvement 







On the place where phosphor layer fell off blue tint appeared...







*So what do you guys think about this method? Any experience?*


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## Harold_B (May 4, 2013)

I wouldn't use gasoline since petroleum products can damage the encapsulant and other materials. We use IPA to remove silicone from LEDs although we usually take the phosphor layer too. There are a few white papers out there on silicone rework if you do a search.


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## Tatjanamagic (May 4, 2013)

I did research and I felt qualified only for this method. Only procedure is to soak and put it out...

On "other forum"( I am not member) very popular method... Seriously plenty of people doing that with success only I fail


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## Rovert (May 4, 2013)

I have done it with Gasoline, maybe i did it wrong, the dome became very crumbly & did come off but not very cleanly.
I do however have 100% sucess with using a scalpel.
Biggest problem is my eyes not being able to focus to such a tiny area.
I now use a magnifying visor & it is really easy.
I just run the led until i think its fairly hot & go for it.
I have now de domed around 10 xml's & 2 xml2's with no failures.
Cheers.


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## Tatjanamagic (May 5, 2013)

Did you put it in gasoline for few hours or 24 hours? 

So on CPF this is not very popular method. Or maybe plenty of people did not tried that.


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## bshanahan14rulz (May 8, 2013)

Thanks! IPA I must try!


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## Harold_B (May 8, 2013)

More info if you want to look for alternatives: http://www.electroiq.com/articles/a...-for-removing-silicone-a-practical-guide.html


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## Tatjanamagic (May 24, 2013)

So no one wants to try  ?

I assure you that it is working...

I did mistake on first attempt of XML de doming by soaking whole pill upside-down in shallow gasoline bath...


- What you need to do is to soak emitter on star only and put more gas into glass 
- Star needs to lay on the glass button while led must be on upper side. Something like this:




- Few hours is enough (about 5-8 hours)
- dome will just pop by itself 
- Just spray it with contact spray(some guys just rinse it under water) - it will clean remaining silicone
- Don't touch phosphor layer even if it has some miniature silicone leftovers. Or just use tweezers around emitter to clean that. 

Final results:





This should be 100% successful method if following this instructions.

*Please try and report*


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## mesa232323 (May 24, 2013)

Will de doming improve throw on an aspherical lens flashlight?


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## Tatjanamagic (May 24, 2013)

*Yes! Absolutely! De doming improves throw in aspheric!*

Some guys on CPF mentioned that it will not improve... Even much experienced than I am... You are very wrong guys! 

Look here:
http://www.candlepowerforums.com/vb...ON!-Nightmaster-V2-host&p=4195456#post4195456


*Expect at least 30% throw improvement and maybe even more *


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## vestureofblood (May 24, 2013)

I started doing them like this recently as well. It leaves a far cleaner surface then getting them hot to pop it off.

I use high octane with no ethanol over night. After removing what crumbs I can with a tooth pick ( be very careful NOT to break the wires on one side) I pinch em with some hemos and give it an easy blast with my compressor to get the crumbs out from around the wires.

Since gasoline leaves a residue behind I wash the emitter with rubbing alcohol to remove the left over oils. 

Doing this carefully makes the emitter look almost as if it never had a dome in the first place.






Mesa23,

de-doming XM series emitters will give you about double your lux with an aspherical flashlight. Putting the emitter on a direct bond copper MCBCB so you can drive it at two times the current gives you another significant percent on top of that.


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## Tatjanamagic (May 28, 2013)

Glad that even professionals like *Vestureofblood *use this method... Yes it takes a lot more time but it pays off eventually because even total noob can de-dome this way...


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## valravn (Jan 5, 2014)

I just did my first dedome. 
i used a razor blade on a torch i bought at an discounter a few months ago for about 8€. 
I think i has a cree xp-e, and it has a 2cm aspheric lense.

i was 95% successfull, only two very tiny dark spots near the edge. 
here are some pictures, but my camera is not very good and the voltage of the batteries was low already (3xAAA at 3.8V idle) 
https://dl.dropboxusercontent.com/s/8q4mwgctde4xqpc/P1010855.JPG

compared with my (fully charged) srt7 on maximum, 15m distance, 30cm ruler in the image:
https://dl.dropbox.com/s/4jfpsj2tacix4oo/P1010857.JPG

it seems, to mee, it works on aspherics as well. the outer (dim) square is the illuminated die, and as such the size the original spot was aproximately.


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## TEEJ (Jan 5, 2014)

It absolutely works on aspherics, as it reduces the apparent size of the emitter. That puts the same lumens into a smaller point of emission, which is what is projected, a smaller, brighter image/hotspot....increasing throw. 

This also works with a reflector based light....as more light is in the hotspot. 

I've been seeing ~ 2x the cd from dedoming. As Vesture also noted, if you also use the copper to allow a higher drive juice, that can also add still more throw.


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## John_Galt (Jan 5, 2014)

Has anyone tried dedoming an xp series led and then testing with commercial optics? Ie carclo 20/30mm optics?

Thinking of rebuilding a led offroad light I have and want to maximize seeing distance.


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## medic265 (Mar 9, 2014)

Please forgive my newbie question...

So this gives supstantial more light using an aspheric lens? And I understand the aspheric lens to be what focuses the beam?

It may have been stated, but this does create more heat I assume?

And then just to be sure, this also creates more light with a reflector?

Please forgive my newbie questions. I'm trying to pick up on all the "lighting" lingo...


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## Fireclaw18 (Mar 21, 2014)

The dome on top of the emitter does 2 things: 
1. it allows more light to escape the die crystal, so increases lumens.
2. it magnifies the image of the die, decreasing the effective luminance... so fewer lumens are produced per square mm, but it makes up for it with a larger apparent surface area.

De-doming the emitter does the following:
1. Decreases lumens. Overall output of the LED will drop maybe 15-20%. In a small zoomie this means you get less light coming out the front.
2. Shrinks effective die size. The image of the LED you see in spot mode won't be as wide as with the dome on.
3. Increases luminance. the image of the die will be much more intense giving a dramatic increase in lux (sometimes upwards of 50% or more increase in throw).
4. Shifts the tint. removing the dome will cause the tint to shift usually making the light look warmer, or sometimes yellow or green.

The only reason to de-dome is for the dramatic increase in throw. If you want a light to throw as far as possible, dedoming is the way to go.

To answer your other questions:
1. Dedoming increases throw with all types of optics, including both reflectors and aspheric lenses.
2. Dedoming creates no additional heat. The LED draws the same amount of power and produces the same amount of heat whether domed or dedomed.


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## schizeckinosy (Mar 21, 2014)

I have been using gasoline with good success. On a whim (and because I was lazy), I left an XML2 in gasoline for a week. Besides popping the dome off, all of the silver paint came off of the emitter, leaving it a dark copper color (I suspect it is copper  )

Importantly, the maximum lumens from this long-soaked emitter dropped to around 400. I suspect that the gasoline eventually interacts with the phosphors or diode itself, rendering it less efficient. I saw no such lumen decrease (except for the expected drop from dome removal) on emitters left a few hours or overnight.


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## m4a1usr (Mar 23, 2014)

Fireclaw18 said:


> The dome on top of the emitter does 2 things:
> 1. it allows more light to escape the die crystal, so increases lumens.
> 2. it magnifies the image of the die, decreasing the effective luminance... so fewer lumens are produced per square mm, but it makes up for it with a larger apparent surface area.
> 
> ...



All good issues to point out but you forgot another issue that is no so obvious to many until they remove the dome. Color change. I have noticed, especially with XPG/XRE and similar LED's a significant color shift when taking off the lens. I'm "fixing" a Malkoff Hound Dog currently that the previous owner de-domed and it now has greenish tint. I bet Gene wouldn't approve.


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## schizeckinosy (Mar 24, 2014)

It's #4


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## kosPap (May 9, 2014)

hi guys!

I am new on this trick and i ahve a question....
After dedoming, is the LED die covered with soemthing or you just use it as is?


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## bshanahan14rulz (May 12, 2014)

Just use it as is. I don't know what the phosphor layer is made of, had assumed it was silicone too, maybe the phosphor particles give that silicone more stability so that it doesn't just fall off with the dome, or maybe the phosphor particles are embedded in a different optical material.


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## kosPap (May 12, 2014)

thanks


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## Fireclaw18 (May 12, 2014)

kosPap said:


> hi guys!
> 
> I am new on this trick and i ahve a question....
> After dedoming, is the LED die covered with soemthing or you just use it as is?



Some people coat the LED after dedoming with LEDSeal to help protect the phosphor layer and die wires.

Personally, I just use as-is with no added coating or protection. Seems to work fine.... but do try to avoid touching the top of the dedomed emitter. It's much more delicate than with the dome on.


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## kosPap (May 17, 2014)

that is what i wanted to hear..Thanks!


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## CyclingSalmon14 (May 17, 2014)

Will this work with UK "Petrol" and right pain though as I think you have to buy 5/10 L minimum, and 1L would be enough for like 25/50 attempts lol if you only did one at a time, but petroly is super cheap only £1.50 or so for a L so cheap I guess (until you have to fill a whole car!!!!)

Is there anything else I could use that would be able to get in smaller quantity but still cheap?

Anything I might already have?


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## FRITZHID (May 18, 2014)

"White gas" for liquid fueled lanterns may work.


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## Fireclaw18 (May 19, 2014)

FRITZHID said:


> "White gas" for liquid fueled lanterns may work.



I use Coleman fuel for dedoming. It's probably not as good as gasoliine, but it's what I had on hand and seems to work.

With gasoline dedoming, supposedly the best way to do it is to place the star with the LED on it so that it hangs face down while immersed in the gas. Do this for 24 hours and the dome is supposed to be completely gone with no further action needed.

I do the same thing with Coleman Fuel. Coleman doesn't disintegrate the dome though. When I pull it out after 12+ hours soaking, the dome is still there. I then take the side of a flat toothpick and push the dome off in the direction of the bondwires. It comes off in one piece, usually with no further work needed.

After pushing the dome off I give it a quick rinse in Isopropyl alcohol to remove the fuel.


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## kosPap (May 23, 2014)

I am about to try it with stain remover gasoline


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## bshanahan14rulz (May 23, 2014)

Is it that hard to get gasoline across the pond? Here, you can bring a gasoline canister to any fill station, toss 'em whatever change is in your pocket, and get that much worth of fuel. I just squirted a little bit of gas in my spare gas canister I keep in the boot one time when I was filling the car. All of maybe 100mL 

Would be neat if we could buy a gallon of industrial purpose-built silicone solvent and part it out...


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## dazed1 (May 27, 2014)

It it safe to clean off the led it self from the parts/lefotvers of the melted dome? if so how to do it? can i brake the wires on the led it self? scratch the surface? will they drop of from washing under water? Does leftovers/grease from gasoline, lower the transparency of the led it self, hence you guys are removing it with alcohol?

Also does dedome with scalp, offer less output loss then gasoline method?


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## bshanahan14rulz (May 28, 2014)

The feature of the dome that increases the LED's efficiency is the curve of it. If you leave the dome on but slice it perfectly flat right above the LED, you will still have losses.

As for cleaning off the LED, usually not necessary. I used a very fine needle to pick at the bits that weren't close to the LED chip or the bond wires, but I just left the stuff near the bond wires. I don't know, they're metal, and pouring alcohol over it shouldn't dislodge them, but they ARE very fragile.

I'd avoid touching the LED chip entirely. The phosphor is likely embedded in silicone too, not really sure how it doesn't get removed in the dedome process, maybe it is just phosphor pigment with binder that isn't as incompatible with petrol as silicone is. Either way, the surface of the LED is very very delicately patterned, and white LEDs have a coating that isn't realy bonded to the LED, just applied to it.


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