A Perfect Dedome?

There's no SinkPAD for XRE's?? For XRE's, limit is about 2.2 - 2.4A or so, I've used 2.45A for A60's, maybe not much more than 2.1A. I'm using XP-E2/SinkPAD's now in A60's at 2.8A -- Match's tests still show a rising lumens output at that amperage, but not rising much...

Good question - I think the MTG and XML pads are too narrow, and Sinkpad doesn’t seem to list it.

depends on your XR-E. people here have gone north of 2.5A with white R2s, and that’s without copper PCB.

I can say from experimentation that the green ones are not as robust. Also, the Vf on greens seems to be much higher than white - ie I can direct drive a green xr-e off one CGR18650CH and it won’t eat over 1.4A because of the Vf, but that doesn’t seem to be (as much of) a problem w/ white xr-e

I sent an XR-E R2 to Match and there’s a graph of his test on here somewhere…

edit: also, I flowed an xr-e to a copper sinkpad, and w/o an good tests to back it up, I’d say its a toss up between using that and an aluminum pcb (w/ proper xr-e solder pads), because you lose so much contact area on the center pad.

nope, I asked them directly.

and since it isn’t something they already make, they won’t mix it into an order like they did with out xml/xpg orders.

I just did my first on-purpose xml dedome while the led was in place in flashlight. It worked great. Did it as follows:

  • I lifted the led base off the pill so it would have no heat sinking. Turned on the light to high. This is a cheap zoomie with stock driver. High is less than 2 amps, probably around 1 1/2.
  • I darted into another room to grab a sharp pick. Took probably less then 20 seconds. Smoke was coming off the led/base. I turned off the flashlight. Took the pick to the dome and the led slid right off the pad. I quickly slide it back on to the pad. I took advantage of the accidental reflow moment to push the led down and squeeze out the excess solder. I then gave it a few seconds for the solder to solidify.
  • I then carefully stuck the pick fairly low on the doom on the opposite side of the bonding wires. I put gentle upward pressure. I could see an air gap starting to form in one corner of the led, but I could sense the led was cooling because the doom felt like it was stiffening. I turned on the light to heat it up. When I started seeing a little smoke again, I turned it off. Carefully made sure I didn’t reflow again. Lifted the doom more. I was very cautious and repeated turning on and off a few more times, but only for a few seconds (before it started to smoke).
  • The dome came off clean off the top of the led. No residual silicone on the led. The phosphorous looked perfectly intact. Very clean looking. The silicone sheared off above the bonding wires. Perfect, I wanted them to still be protected. There was also residual silicone on the led’s pcb around the led. I left it in place. Pushed the led base back on to the pill and reassembled the zoom and lens to the flashlight.

The light worked great. Reduced the size of the flood, but beam is more intense and warmer as expected. Image of led zoomed out is clearer. Then I got over confident and picked off the residual silicone that was around the led. I did this whiled the led was cold. It peeled off easily. But apparently, it was still bonded to the edge of the phosphorous and pulled a couple small chunks of phosphorous off. You can’t tell with the naked eye, but when the light is zoomed out, you can see the missing chunks in the projected image of the led. Not a biggie because I don’t use full focused zoom in real life. Too distracting. I take it just out of focus so I can see what I am actually trying to light up better.

I have done it with slight cutting then heating and pulling off with tweezer some times and it works every time. The dome is clear and the bond wires still a bit messy…
Is this as easy with an XML2?

There may be an even better way. All you have to do is build a rocket to launch the LED to fly close to the sun to heat up the dome, then a super-intelligent robot can poke it with a pin and peel the dome off. Do you think that might work better than just dunking the damn thing in gasoline and then a few hours later like magic you have a freshly de-domed LED?

Been there, done that. Problem is robots eats phosphors…

I get the impression you may be mocking me. That’s cool. It’s all good with me. I’m telling you though, the led was clean and probably took less than a minute to dedome (not counting other issues). No left over gunk like I see in most of the pictures using gasoline.

Have you tried it? What's left cleans off very very easy. Just crumbles away. A spritz of rubbing alcohol from a spray bottle gets rid of most of it. Anything left after that falls right off with a little brush from a pointy piece of plastic.

I think most of the 'after' pics of the gas method are taken before it's been given a final cleaning, which might be what's throwing you off.

No, I haven’t tried the gas method yet. I wasn’t trying to dis that method. It sounds like a good approach.

I was just being lazy and in a hurry. Turned out it worked quite well. In hindsight, it makes sense because the hottest spot is the led itself. The thing you want to get the silicone off. Was just sharing my experience with a method I haven’t heard about yet. This thread seemed like the best place to share it. If it wasn’t, I apologize.

No no, it's just that I tried (most) all the other methods too and they were miserable failures, not a single one of them worked afterwards for more than 3-4 seconds before going POOF. I've done 5 or so with gas and all have been perfect.

Thanks for sharing ImA4Wheelr. I’m a gasoline dunker myself, but the best method is what works for you.

I haven't had much time for experimenting, but did 2 gas de-domes today, my 2nd and 3rd, both look perfect, and it only took 6 hours in the gas, because I checked and noticed one dome was completely off and the other was floating up, dangling on.

XM-L2 T6 0D:

XM-L2 U2 1A:

I fired up both just to test and they both were blinding - duh, don't look at the LED while testing! The U2 1A is going in a T08 mod'ed up, hoping to achieve some big numbers.

it made a significant increase in lux when I de-domed an sst-90 - but its late and can’t recall the % gained :weary:

same w/ green xp-e - but I think that tiny little emitter has enough problems w/ artifacts before a de-dome and I might not do anymore. at least w/ those you don’t have to worry about phosphor damage…

Tom, please report on how was the tint shift on that 0D XM-L2 T6 you dedomed, I am hoping that it will shift to a 2A or 2B tint.

Thanks!

We were thinking that 0D would would warm up nice, hoping next day or two. Little backed up now . Just de-domed it because I was doing the other light.

Finished this mod. Tested it out in the C8 pill and it warmed up nicely. I'm a bad judge of tints though and don't think my pics would do it justice. Compared to a 3C? Maybe close - think it warmed up quite a bit, maybe warmer than 2A or 2B.

Thats good news TomE. Thanks was wondering the same thing as AlexGT

I soaked a xre in gas for about 24 hours and the dome was gone. Then I tried to pop off the ring and upon doing so I damaged the led someway and it doesnt work. I then did another for about the same amount of time soaking and popped off the ring this time and it still works! Success with the xre! Thanks for whoever posted about popping the ring off after soaking in gas, I tried to pop it off after a dedome with out gas and it wouldnt come off.

I am now soaking a green xre with hopefully good results.

Please update us on that. I might want to try a red.