C8 XML de-dome & reflector mod

You de-domed by slicing the dome off with a blade, leaving a thin layer of ‘dome’ on the die?
You could try melting off any dome that remains with gasoline / petrol. Drop led in glass of fuel, cover, come back around 24hr later, several people say it works great.

How to clean off the gasoline afterward?

If you sliced the dome already, it might only need a few hours. I did one I sliced first and it fell off after just three hours or so.
I just wiped off the star and didn’t touch the emitter at all. I let it dry for a bit and that’s it. Others may clean with something else.

I asked isopropyl alcohol to clean it after gasoline - seemed to work well.

I see. So by using gasoline the dome was completely fell off, did you guys use anything to “seal” the emitter or just let it be?

There's some guys using LED Seal, but I think you lose a little output from it, and there are other guys that posted they've used a de-domed light for one year and no problems at all. More info here: https://budgetlightforum.com/t/-/17374. Some say the small, frail wires are gold, so they won't oxidize or anything, and the emitter seems to have a coating on it anyway.

For me, when I get a chance to do a couple of more de-domes, I'll use the gas soak method (24 hrs+), verify all the silcone is off the LED, pour some isopropyl alcohol over it to remove gas residues, and leave as is -- that's the plan anyway. It seems to be the best, easiest way to go.

So dunking the LED into gasoline is a 100% successful de-doming method?

I’ve done one that way, so for me it’s 100% success :smiley:
This seems to be the most successful way to do it. The key is adequate time. If you do not wait long enough, you may break the bond wires. The dome will basically fall off, so you should not have to do anything other than maybe gently shake the dunked emitter to see if the dome will fall off.

Well, if you saw my thread, I'm 1 for 1 using gas, and my other methods, batting 0% . The only thing guaranteed is death and taxes .

It just seems the most reliable, accept for those with special talents and setups for heat methods. Some guys also had successful acetone de-dedomes, all I know is gas seems to be the easiest and seems to be reliable, and appears to be the latest recommended method from several people.

From my failed acetone method, I believe relic38 or dthrckt (?) mentioned if there's still hard silicon or any silicon left covering the emitter, re-soak it for a while. If I were to try acetone again, that's what I'd do - re-soaking until it falls off or comes off easy.

Manual Man posted impressive de-dome results here: https://budgetlightforum.com/t/-/17492#comment-364296. Just posted a Q of what method he used.

Yep, I sliced it with a thin razor, but it was a little more resistant than I expected, so I had several hacks at it, & it looks quite uneven through a magnifier.

I might take it into work today & dunk it in some solvent for a while.

The solvent (75% naptha) didn’t really ‘melt’ it, rather made it crumble off, unfortunately taking off one of the connecting legs in the process… Good news is that it still works, but seems to pull slightly less current ~2.19 amps.

It seems to have cleaned things up a little, the lens is off-center though.

I have just dedomed a xre with petrol .then into acetone to clean off any residue.

So I just wanted to ask if others think it is worth it to de-dome an XM-L T6 in a C8 or not. I have one and was thinking about doing it. I also have a Jacob A60 on the way so I am wondering if de-doming the C8 will give me a beam like the A60? If so, then I don’t see a reason to de-dome the C8. It has a nice hotspot as it is, but I would possibly like more throw. I was thinking about doing it and ordering an XM-L2 U2 or something to swap in anyways. So if I ended up not liking it, I could just swap any ways. I also have a UF WF-501B with a T6 that I could de-dome as well as 2 UF SK68’s and 2 SK98’s (one with an XM-L T6 and another with a XM-L U2-or U3). Would it be worth it to de-dome an SK68 or possibly an SK98? From my understanding de-doming a led in the SK68/98 will give me less flood but more throw, right? Thank you for any and all help. I’ve been trying to read up and see what the difference is and if it is worth it. I haven’t been to successful, otherwise I probably wouldn’t be posting asking lol.

Here's a comparison of a dome-intact P60 and a de-domed C8. That's the closest I can get, I don't have a C8 with a non-dedomed LED right now.

P60 was at 2.8A, C8 at 3.2A. C8 using the XR-E reflector (with the wide flat area around the emitter hole), it throws better than the C8 XM-L reflectors.

Ahh you’re the guy with the ridiculously awesome scenery in beamshot pics :slight_smile:

Cool stuff!

It sounds to me like you have set to high temperature on your soldering iron or (if not regulated SI) is too powerful!

Thanks for the advice, I’ve since purchased several different size/temperature tips for my Weller iron.

The only tip I had when I started modding these tiny components was an old ground down tip that was about 1/4” wide :smiley:

I completed and tested a C8 pill last night - Nanjg @4.2A (12 x 350 7135's), measured 4.40A on a Samsung 20Q, de-domed XM-L2 U2 1A from IOS. Without any attempt at focusing the emitter and using the stock lens, measured 102 kcd, taken at 5 meters. So, this C8 can really throw, and compared the beam to a stock A60 and it's definitely a bigger hotspot, and of course has a lot more light in the spill. With aspherics, specially these plastic lens, you lose a lot of lumens compared to a reflector light, but you should see an advantage with de-doming them for throw. Note, you lose approx. 15-20% of lumens and can double your kcd when de-doming. That C8 pill I did would probably be about 45-50 kcd if not de-domed. de-doming doesn't reduce the flood area, just lessens the brightness of the flood area from what I've seen in reflector lights, think same is true for aspherics.

I would say give it a go if you’re after an improvement in throw. I’d also recommend it if you dislike the tint for being far too cool/blue and want better contrast and definition when scanning distant vegetated areas (because of the extra green light).

As you can see from those great beamshots, a full gas dedome usually does some predictable things to the tint.

1. It warms the colour temperature quite a bit, I think I’ve seen figures of around –1000k which feels about right to me, could be more even.
2. It pushes the tint considerably towards the green side of the chromaticity scale.
3. It removes basically all of the famous XM-L chromaticity variation between spot and spill. A big benefit that I like a lot, also makes the new tint more acceptable to my eye since whatever it ends up being it’s the same right across the beam profile.

With that in mind my best results in terms of dedoming have been with the coolest/highest output bins and in particular tint bins that are more on the purple rather than the greenish side of the chromaticity diagram. For XM-Ls that would be a u2/u3 in the 0-1 and A/D tint range.
Anything that is already more green to start with will just become far more so afterwards, maybe to an extreme extent.
Wonder what those really green U3-2S tints would look like dedomed!! :stuck_out_tongue:

I haven’t dedomed any XML2s but I’d imagine the same rules would apply.

In terms of success rate with the straight gas method, I’ve done 3 and all have been a complete success. Would highly recommend this method over anything else.

Good luck!

Well I went ahead and de-domed the C8 tonight. Put it in some gas for an hour and a half to two hours and it came off while swooshing it around in the gas. I think it did give me a little more throw and a warmer tint. I am happy with it so far. Thanks for the replies guys!