Questions about dedome

Hi need to know some stuff about dedome.

I have on order, XM-L2 bare leds.

The led need to be mounted/glued? on Fenix TK61 copper pcb. It will be hard to mount it i guess ? :frowning:

My friend will do the mod for me, and i need to know…

1.How many contacts are on the led? 2 or 3?

2. When you dedome, i heard there is a direction, which you need to follow > push the dome, in order to not damaged the led it self?

3. Is heating the best method yet?

4. Would the leftovers from the dome, limit the performance of the led? how to remove the leftovers, knowing there are “wires/contacts” on the led itself?


I would mount them on an old star, attach a lead to the star and hang them in gasoline for 2-5 hours. It is slower than the heat method, but soo much more simple and easier to boot.

First one I did was in a colder environment ~65*F and it took over 24 hours, but all since have been done in ~90*F and they fall off very quickly (usually less than 5 hours for XM).

Mount the LED on the star you’re going to use…copper is best. The bare LED must be reflowed (soldered) onto the star. There are three pads on the LED. The outer ones are pos. and neg. The one in the middle is the thermal (heat) pad.
Once the LED is mounted, there are two (+/—) pads on the MBPCB.
Solder a wire to one of the pads and hang it in a jar of gasoline. Once the dome falls off, rinse the emitter and star in alcohol. After the dedome, be very carefully of the exposed LED.

I dont like gasoline method, because it will produce an awful green tint. Thanks for the answers guys!

P.S. I will use the Fenix star, like it was on stock led. keep in mind, we damaged first stock led, now we will use other bare XM-L2 led.

Gasoline doesn’t have any deciding factor on the dedomed tint. What tint you end up with depends on the tint of the LED you are de doming.

i was told, the gasoline make the tint green, by vinhn, and its logical when you think about it. The gasoline removes/resolve the phosphor of the led a bit, ending with greenish tint. With heating i think you can never have green tint after the dedome, i might be wrong, not sure.

If a friend does the mod for you, he doesn’t know what he’s doing?

He is very skilled, but he need some info to make it easier, it would be his first time.

That sounds like him trying to hint at someone else’s method being wrong even tho it’s not. The petrol doesn’t effect the phosphor at all, it ONLY effects the dome. It is without a doubt the recommended method for beginners. Did you know the emitter actually has a 3rd bond wire not even attached to the die? I say this cause its hard to watch for when trying to lift the dome having never done it before to know where it is, they’re fragile, brain surgery level care is required working around them, break just one and you flushed $3-7, worst part is with only 1 broke the led will still light (just at severely reduced output) so just a quick zap of batt power to test of it works before install won’t tell you if its good or not cause it will light up broken. You even think you got close you either have to look with magnification or put it together and see.
Another options is when he lifts them he’s not letting it get fully hot and leaves a thin layer of silicone, that would drastically reduce the tint shift.

For me I only use gas and it takes about 2-4 hours (depending on how fresh the gas is, I put a little in a glass jar and keep it around to reuse, as it gets older and filled with more and more silicone it starts to work slower, fresh gas should take around 2 hours).

From my personal exp the tint is EXACTLY the same from either method, one method is just many times less risky, almost fool proof. I’ve dedomed around 40 emitters from XP-E2’s all the way up to a MT-G2 and an SST-90, the ONLY 3 that the gas has ever effected was 3 very old original XP-G R3’s, on those 3 it DID eat the phosphors right off, there was no yellow left and the beams were pure blue but no Gen 2 cree emitters, any gen XR-E or any other brands have ever had the phosphors effected even the slightest.

I agree with Ouchyfoot that tint depends on the LED and not the method of removing the dome. I have done it both ways and it is luck of the draw on getting a suitable tint (not green or blue).

Oh that’s very good news. Any info of what gasoline?

It might be not Vinhn who told me about tint shift, (with gasoline) not wanting to make this on him. I read and talked with so much users lately that i might have mixed things up, sorry guys!

Is zippo gasoline better option? you guys say 2 hours is good enough? what about bare emitters? should i somehow make them not float around? (put something heavy on the bottom?)

Also one more thing, does gasoline makes the silicone disolve and harder to remove the leftovers compared to heat method which takes of the dome totally?

Please point me the ultimate hints during the dedome, and how to remove the leftover safely? can my friend gently remove the leftovers from the led die, after the dedome? with some cotton or soft cloth or he should never touch it?

I use standard 87 octane gas, about an inch in a baby food jar, use the lid. Zippo fluid may work, I know some people use other types of solvents, I haven’t tried cause I get great results with gas, why try to fix something that ain’t broke (I do enough of that, I am a flashaholic afterall lol) but seriously I’ve never felt the need to try to change the process any, it works fine exactly how I do it now.

I would put the LED on the MCPCB first, it’s so delicate after its dedomed you dont even want to try to grab it with tweezers, its better to have the MCPCB so you can handle it. drop it in the gas and leave it a few hours, go back and swish it around, the dome will fall off in one piece, no left over silcone to worry about, it comes off clean. When swishing it around use a circular motion with the MCPCB against the edge of the jar spinning, you dont want it to flip over, it might crush the bond wires.

To speed up the process I will slice off the top part of the dome, I dont even get near the die / wires, just about 3/4 way down, this isnt necessary at all it just speeds the process up a little, I can have a emitter dedomed and back in the light in just over a hour this way cause there is less silicone for the gas to have to work on.

Do not dedome the bare emitter. It must be mounted on a star before dedome or you will damage it. Use the same gasoline as you put in your car. The dome should fall right off. Rinse in alchahol. There should be nothing left over. Do not touch the dedomed emitter.

So my friend should first glue/solder the led to the Fenix TK61 copper pcb, and then dedome? then rins the gasoline leftovers with etanol, and dry it off, put it back into the light - done, is that all? :slight_smile:

Thanks so much!

no glue involved, just solder but yes thats all

Thank you guys! how much lumens should i lose from stock? around 15% after dedome?

You are still butchering your TK61, poor light :stuck_out_tongue:
Dedome is always fiddly job, you need at least x5 magnification glass to see what are you doing and there are always leftovers of the dome that you need to clean afterwards, you should have ordered double quantity than what you actually need…

Yea i guess :smiley:

Problem being, long shipping time of the leds, the stock one we ruined. I have 3x XM-L2 U2 1A on order, if we ruin 1, or green tint we go for the second one and so on :smiley:

BTW, how do you guys clean the leftovers? under stream of water maybe?

..and after the third one you order a larger batch. ;)

Stream of water might be enough to break the bond wires.

I use a steady hand, jeweller's loupe & wooden tooth pick. :)

Thanks guys! toothpick might do the job i guess (under loupe ofc)