A Perfect Dedome?

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Bort
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Ledsmoke wrote:

Putting a XP-G in gas oil for 24 hours works fine.

The dome did not fall off by itself though. What happened was that I thought it had not worked so when I took it out of the gas oil i poked the dome with my finger to feel if it had gone soft at all. It had not really but it just slid off!

I then sprayed the die with electro cleaner for a few seconds and that removed any gooey stuff that was left.

Initially worried that I might have broken the bonding wires with my thick fingers I hurried to test it out with a battery and it works.

 

Thank you very much to the OP and all others who have contributed to this thread and the knowledge we now have. TY! Smile


will the electronics cleaner do the de-doming i wonder?

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texaspyro
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Bort wrote:
will the electronics cleaner do the de-doming i wonder?

No, they are made to not mess up plastics and similar stuff.

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texaspyro wrote:
Bort wrote:
will the electronics cleaner do the de-doming i wonder?

No, they are made to not mess up plastics and similar stuff.


how about WD-40?

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

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Bort wrote:
texaspyro wrote:
Bort wrote:
will the electronics cleaner do the de-doming i wonder?

No, they are made to not mess up plastics and similar stuff.


how about WD-40?

Very unlikely. WD-40 doesn’t attack silicone very well – if at all.

This stuff would probably do a great job. It dissolves Silicone amazingly fast.
http://www.techspray.com/download-tds-document.php?pId=153

I am currently extremely busy with work. Please do not expect a response from me quickly. I will be dropping in as time permits, but the amount of time I can dedicate to responding to topics and PMs is very limited.

texaspyro
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PilotPTK wrote:
This stuff would probably do a great job. It dissolves Silicone amazingly fast. http://www.techspray.com/download-tds-document.php?pId=153

At $35/pint plus hazmat it also dissolves your wallet contents amazingly fast. Wink

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I found here on a dutch forum that an electronics guy used petroleum-ether to remove silicone remains. I have some here where I work, I will give it a try.  The composition is not far from gasoline, but it is much cleaner. It is even more equivalent to Coleman Fuel (which is also much cleaner than gasoline).

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sounds like it is equivalent?
http://en.wikipedia.org/wiki/Petroleum_ether

coleman fuel is pretty cheap around here (~$10-$12 a gallon). Which makes me wonder who pays $10 a quart for naptha (same thing different label).

its also a solvent/thinner for plasti-dip Silly

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texaspyro
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djozz wrote:
I found here on a dutch forum that an electronics guy used petroleum-ether to remove silicone remains.

I doubt that it will work. It is a pretty mild solvent. Good on sticky residue from tape and tends not to harm most plastics. I use it for polishing plastics and LED display windows with red jewelers rouge.

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I tried lacquer thinner the other day. Oddly enough (imo), it seemed to be less effective than acetone.

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The petroleum-ether I have here says: 100-140°C. I may have some Coleman Fuel as well somewhere. Perhaps when I can find some time and enough spare leds I will do a 'great dedome test string' one of these days..

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texaspyro wrote:
djozz wrote:
I found here on a dutch forum that an electronics guy used petroleum-ether to remove silicone remains.
I doubt that it will work. It is a pretty mild solvent. Good on sticky residue from tape and tends not to harm most plastics. I use it for polishing plastics and LED display windows with red jewelers rouge.

It seems like it is not necessarily the most agressive solvent that works best on led-domes, I'll try it anyway Smile.

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Anybody de-domed an XRE? Same process?

Will the metal ring come off without damaging anything?

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metal ring doesn’t come off with acetone.

good luck getting all the silicone out of the inside of the ring, and enjoy the ugly artifacts that the inside of the ring makes….

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I’ve done a few XRE and XRC, just grab the metal ring with a plier and pull/twist it off.

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fonzeka wrote:
I’ve done a few XRE and XRC, just grab the metal ring with a plier and pull/twist it off.

After, before soaking in gas, or instead?

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GottaZoom wrote:
fonzeka wrote:
I’ve done a few XRE and XRC, just grab the metal ring with a plier and pull/twist it off.

After, before soaking in gas, or instead?

I never had any luck with the XRE twist, always some bad residue left behind. And removing those always a mess. My success rate is only 33%, 1/3 – one ruined wire, one bluey, and one not-so-good-but-I-leave-it-alone-anyway-otherwise-rate-would-be-0/3… heheh.

With petrol soak, the whole ring and dome just slid off. I have 100%, 1/1 success on this method for XRE. Best, cleanest result out of the four too.

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dthrckt wrote:
. . . and enjoy the ugly artifacts that the inside of the ring makes….

LOL, I’ve got a zoomie with that problem already from a thick hold down ring – the ring reflection is outside of the beam, but still wanting to paint it black.

No, I’ve got a spare XRE and if I de-dome the ring will go even if that ruins the emitter.

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GottaZoom wrote:
fonzeka wrote:
I’ve done a few XRE and XRC, just grab the metal ring with a plier and pull/twist it off.

After, before soaking in gas, or instead?

I did them dry.
It was a while ago so I don’t think the gas trick had been invented Smile

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fonzeka wrote:
I did them dry. It was a while ago so I don’t think the gas trick had been invented Smile

Thanks guys. Think I’ll try the soak first, then pull if needed.

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i’m going to have to try gas on an xr-e. I’d LOVE to get a clean/no-ring de-dome.

2x the current of xp-e…should be quite a thrower

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I have used the heat method with near 100% success. Fairly sure given 100 XML or XM-L2s I could do every single one of them without failure now that I have the technique down.

I have done approx. 2 dozen XMLs (+ two more this morning), an XP-G2 and a XP-E.

I find it easiest to do if the LED is already mounted on a MCPCB in a torch. From there I remove any screws or glue etc and lift the board so the board is “floating” in the air with the leads still attached. I then run the torch on high until the board is too hot to hold.

Placing my figure as far down the dome on the opposite side of the bond wires I peel towards the wires slowly: you will notice if the heat is not right the dome is harder to peel off. If doing this for the first time have a play with peeling the dome at different temperatures and try get a feel for how hot it has to be. You can reheat the LED at any time during this process.

The result is almost exactly 110% increase in lux for reflector lights.

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No solvents are needed. I just let my led heat up a bit by running it away from a heatsink until it gets good and warm, not burning up hot just hot.

I then stick the razor into the dome a bit adjascent to the bond wires and open it like tupperware. Basically on an angle and peel the dome off. Had good luck with this method and if any goop is left, the clump stays by the bond wires!

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djozz wrote:

The petroleum-ether I have here says: 100-140°C. I may have some Coleman Fuel as well somewhere. Perhaps when I can find some time and enough spare leds I will do a 'great dedome test string' one of these days..

Well, it turned out a not too great test, actually just two old xml-leds and two solvents: petrol and petroleum-ether. Not much news here, but I do have the pictures! Smile. Have a look at my first 'chemical' dedoming session (powered by this thread):

So here are the victims, two spare cool white xml's:

The first thing to do was cutting the silicone away around the cone. can you see the difference?:

So now the soaking begins, the left bottle is petrol, the right is petroleum-ether:

Suddenly it is 24 hours later Laughing, something has happened there under those domes:

So now the dedoming can take off, I even made a crappy video of the first one, it is the petrol one. It is a somewhat messy business this dedoming, no fun. I use a binocular microscope to see what I am doing, the video stops after the dome was removed from the die, it does not show the cleaning up of debris around the die later:

The second dedoming went better, the petroleum-ether seemed to have loosened the dome a bit better than the petrol did. After some cleaning up this is how the leds came out, left the petrol-treated (dirty stuff!), right the petroleum-ether one:

And they both still work, just tested them up to 50mA, but I guess they would be ok in a flashlight. For fun I made pictures of the right led above enlarged and at 1mA current:

So the chemical way worked for my first two tries! I believe I am confident trying this on brand new leds as well Smile.

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Got a “This video is private” error… Please show us your privates!

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texaspyro wrote:
Got a "This video is private" error... Please show us your privates!

sorry, fixed that, there they go Undecided

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djozz wrote:

So the chemical way worked for my first two tries! I believe I am confident trying this on brand new leds as well Smile.

The few times I've tried it, that's what mine look like too except not at 1mA, but at full power |(

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I am the Dedome King Wink! Watch this (in HD ):

Not bad for a very first attempt at hot dedoming Laughing, I am a happy modder.

This is what came out, no further cleaning needed:

And it works (at least up to 50mA, the picture shows 1 mA):

 

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That's amazin stuff! I guess you could reflow, then de-dome in one fell swoop! I assume that's an XP-G2 - you are a better man than I -- I never would have attempted a de-dome technique the first time on a XP-G2.

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“This video is unavailable” error…

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Tom E wrote:

That's amazin stuff! I guess you could reflow, then de-dome in one fell swoop! I assume that's an XP-G2 - you are a better man than I -- I never would have attempted a de-dome technique the first time on a XP-G2.

I did reflow and with the led still hot dedomed it, the video is one shot (and perhaps a lucky one Innocent). The led is a XP-E2 R3, 1D tint.

It is going into my 'budget test-thrower' (49mm reflector, led @2A), just to see what an extreme pencil beam will look like Cool. I may do a beamshot and some lux-readings if it gets finished this weekend Smile.

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