A Perfect Dedome?

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ImA4Wheelr
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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.

comfychair
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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.

dct73
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Thanks for sharing ImA4Wheelr. I’m a gasoline dunker myself, but the best method is what works for you.

Tom E
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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.

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

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…

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AlexGT
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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!

Tom E
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AlexGT wrote:
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 Smile. Just de-domed it because I was doing the other light.

Tom E
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AlexGT wrote:
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!

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.

apt323
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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.

GottaZoom
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apt323 wrote:
I am now soaking a green xre with hopefully good results.

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

apt323
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GottaZoom wrote:
apt323 wrote:
I am now soaking a green xre with hopefully good results.

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


Ok sure will!

Wish they had something like a sinkpad for these. Might have to make it a direct bond to a copper disc and try to over power it to see what power it can take.

Cir2kuk
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Just dedomed my C8 XM-L2 U2 in petrol for 3 hours and the dome just fell off. Smile

Hotspot on the beam is now half the size and twice as bright! Big Smile

P.S im off to dedome my black shadow darth 3x XM-L U2 Wink

hank
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Has anyone sent a dedomed LED to Craig at LEDMuseum?
(I’m not sure if he’s got a photometer right now, but I’d sure be curious to see a spectrum of the output.
I wonder if the dome is doing any significant filtering of light at the UV end of the spectrum, for example)

Tom E
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hank wrote:
Has anyone sent a dedomed LED to Craig at LEDMuseum? (I'm not sure if he's got a photometer right now, but I'd sure be curious to see a spectrum of the output. I wonder if the dome is doing any significant filtering of light at the UV end of the spectrum, for example)

Haven't heard but I don't think I've heard of LEDMuseum either. I could certainly spare a T6 to de-dome, got quite a few laying around from all the upgrades.

Shadowww
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Hm..
I never took a close look at my de-domed XM’L since it JustWorks™, but this thread got me interested, and..
looks like my emitter, that is working completely fine, is supposed to be royally f**ed?! (look at the bond wires)

Here’s a full pic, not like it contains any extra things to see, but I’m just throwing it in since it looks kind of cool: http://shadowww.eu/blf/DSC_0014.jpg

Edit: took a pic of fully lit emitter (taking a pic of emitter in a ~5A direct-drive flashlight wasn’t as easy as I expected!), seems to look somewhat normal. Hm.

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Shadowww wrote:
Hm.. I never took a close look at my de-domed XM'L since it JustWorks™, but this thread got me interested, and.. looks like my emitter, that is working completely fine, is supposed to be royally f**ed?! (look at the bond wires)

How can that work? 1 wire is MIA, and the other is not connected, and discoloration on the phosphor. Wow, amazin.

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Shadowww wrote:
Hm.. I never took a close look at my de-domed XM'L since it JustWorks™, but this thread got me interested, and.. looks like my emitter, that is working completely fine, is supposed to be royally f**ed?! (look at the bond wires) !http://qs.lc/p/oi8.png! Here's a full pic, not like it contains any extra things to see, but I'm just throwing it in since it looks kind of cool: http://shadowww.eu/blf/DSC_0014.jpg[/quote]

That was a truly dirty job, the led should not be working at all, it only has one of the bond wires left ?????? I now officially believe in magic Smile (it seems there's always things left to know about leds)

scaru
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Unless I'm mistaken those wires are only used for positive, all 3 of them and negative comes from below the phosphor, so that should work just fine (but at lower currents as there will be more resistance). 

Shadowww
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Hm, maybe bose301s can solve this mystery? After all, he’s a Cree employee Silly

scaru wrote:

Unless I’m mistaken those wires are only used for positive, all 3 of them and negative comes from below the phosphor, so that should work just fine (but at lower currents as there will be more resistance)


Hey, it tests 4.5 – 5A DD with a Panasonic NCR18650PD Silly
comfychair
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The missing bond wire must be still attached to the die, but laid over and getting power from the one next door. Each bond wire powers a pair of strips, if the lower two weren't getting power you'd only have 4 of the 6 lit up.

scaru
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comfychair wrote:

The missing bond wire must be still attached to the die, but laid over and getting power from the one next door. Each bond wire powers a pair of strips, if the lower two weren't getting power you'd only have 4 of the 6 lit up.

Yes, but technically speaking those strips aren't needed. After all the XM-L2 doesn't use them (and that is how they increased efficiency according to one post I read). 

texaspyro
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I dunked an XRE in Coleman fuel for 24 hours and the dome came off clean. I popped the ring off by using a pair of diagonal cutters at the base as a wedge. The LED worked fine, but the color temp went from 6000K to over 35,000 K! Looks like most of the phosphor came off with the dome.

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texaspyro wrote:
I dunked an XRE in Coleman fuel for 24 hours and the dome came off clean. I popped the ring off by using a pair of diagonal cutters at the base as a wedge. The LED worked fine, but the color temp went from 6000K to over 35,000 K! Looks like most of the phosphor came off with the dome.

coleman fuel?

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texaspyro wrote:
I dunked an XRE in Coleman fuel for 24 hours and the dome came off clean. I popped the ring off by using a pair of diagonal cutters at the base as a wedge. The LED worked fine, but the color temp went from 6000K to over 35,000 K! Looks like most of the phosphor came off with the dome.

Oh Oh, it was me who suggested Coleman I'm afraid Innocent. Can you make a macropicture of the led?

I am beginning to love pictures of damaged leds, here is one of a damaged, but working xpg2 Laughing:

texaspyro
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texaspyro wrote:
The LED worked fine, but the color temp went from 6000K to over 35,000 K! Looks like most of the phosphor came off with the dome.

The XRE that I de-domed was actually an XLAMP-7090, the first gen XRE. The led die is covered by the dome material and then a hard plastic lens. It looks like the phosphor is mixed in with the dome material and not a separate layer on top of the die. Remove the dome and you remove the phosphor…

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I just reflowed a XPG2 die back onto the substrate(!), and the damn thing works. It got overheated during the first reflow and the middle of the die looked burnt out so I tossed it in the gasoline just for entertainment, found the die no longer attached which is why it acted just like one that's running too hot. Put a tiny tiny tiny little dot of solder paste on the substrate, carefully folded the die back down, and hit it with hot air from the butane torch. And the damn thing works now!

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You should ask Cree to hire you, you would lower them the rejects rate Big Smile

P.S. I dunked one XP-G R5 into medical gasoline for about 3 hours but I must have damaged the wires when removing the dome. Damn thing is sooo small, need a microscope to see what am I doing...

 

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Sirius9 wrote:

You should ask Cree to hire you, you would lower them the rejects rate Big Smile

P.S. I dunked one XP-G R5 into medical gasoline for about 3 hours but I must have damaged the wires when removing the dome. Damn thing is sooo small, need a microscope to see what am I doing...

I use a 10x lighted loop - it's not too bad with one hand holding the loop, and the other doing the tweezers. Got the loop from FT - they call it 30x but it's really about 10x and 2 LED's in it throws a lot of light. You have to have both - magnification and light, at least for me...

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Ill take a led that sits on a mcpcb, put it in a little glass jar with petrol, and a lid. Let it stay there for 4+++ hours.
Usually, the dome have fallen of, if not I just “shake” the glass a little bit carefully sideways. When the MCPCB hits the glass, the dome will fall off if its not already off.
So far, I never had to even touch the dome. I always make sure the led/dome points upwards..

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Tom E wrote:

Sirius9 wrote:

You should ask Cree to hire you, you would lower them the rejects rate Big Smile

P.S. I dunked one XP-G R5 into medical gasoline for about 3 hours but I must have damaged the wires when removing the dome. Damn thing is sooo small, need a microscope to see what am I doing...

I use a 10x lighted loop - it's not too bad with one hand holding the loop, and the other doing the tweezers. Got the loop from FT - they call it 30x but it's really about 10x and 2 LED's in it throws a lot of light. You have to have both - magnification and light, at least for me...

I thought to get one of those USB "microscope" cameras! it's easier to work when you have 2 hands at disposal Smile

 

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