depotting glowpowder

I'm attempting a repair on a McLux EN head. I suspect the driver is bad, and that the emitter is OK, but the emitter is potted in glowpowder (all I can see is the dome of the emitter). I'm not sure what the glowpowder is mixed in, it looks like it could be some combination of elmers glue and clear nail polish. I am pretty sure I could get it all out by soaking it in nail polish, but will this damage the emitter? Is there something that will soften up the glowpowder without damaging the emitter, or should I just scrap the whole thing?

bump.

Nail polish remover contains acetone which is not friendly with some plastics don't think I would try it. Is there any way to just chip away at it and get the emitter out then clean it up /ubbthreads/images/graemlins/icon3.gif

Later
Sway

If it was TK or a Hotfoot-made one, then this probably applies -
[ QUOTE ]
hotfoot said:
Personally, I pot the LED up to its neck in Devcon Crystal Clear filled with strontium aluminate glow-powder. The BB pcb floats eternally in a silicone RTV tomb.

[/ QUOTE ]
On the question of how to remove it, I have no idea but I feel I've done my part already. /ubbthreads/images/graemlins/smile.gif
Pat

Q. How do I remove RTV Silicones once they have cured?
A. A combination of physical scraping and a strong solvent works best.
Try our human safe, Ethyl Lactate based Immersion Super Solvent (8260).

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Hi Paul,

That EN head you're trying to fix is the one Josey got from me.

Yup, you're right, the glow powder compound is a mixture of nail polish & IIRC Bostik clear PVA which was a glow powder experiment I think I way overdid. /ubbthreads/images/graemlins/icon15.gif However, I'm not sure if that contributed to the light failing as I had used the light without problem for some time before it went to Josey. If it turns out that it WAS the cause, then I will offer to pay for the costs of repair to Josey.

As to how to remove it, I guess you could try to soften it with a little acetone but as someone mentioned it might affect the plastic elements. So perhaps gently scraping would be better.

Hope you can get it fixed. /ubbthreads/images/graemlins/icon23.gif

Hey Brad-alike,

If it's Devcon CC, good luck. So unless it was some miracle bin Luxeon, I'd just start over. Put this one in a museum (or is it "mausoleum"? I think I read something about eternally floating in a "tomb"?).

Then again it's the circuit that's in the RTV so that is removable, but you'd still need to get the wires desoldered from the board in an intact state, so's you could resolder them onto the next circuit board since you think it is the board that failed. Any way to test the Luxeon?

Right now, I'm sort of chipping away at the glowpowder. It's slow, and I'm worried that I'm going to slip and damage the emitter dome, but I'm making progress.

I am working on the assumption that the converter is bad, possibly suffering from the defect discovered in earlier badboys that caused them to short out through the side edge of the board. The driver is potted in an ecan, so it should be fairly easy to get out once I can get to the emitter leads and desolder the wires.

The leads of the luxeon are under the glowpowder/PVA/nailpolish mixture, so I can't test the luxeon until I get more of it chipped off.

The emitter is a TWAK, so I'd like to salvage it if possible, but it won't be a tragedy if I frag it. I may try to drip a little nail polish remover on the glow powder and keep it away from the emitter.

Update: I dabbed nail polish remover on the glowpowder with a q-tip (I believe these are called "cotton buds" outside the US), carefully avoiding the emitter. I then put some saran wrap over the head and let the nail polish remover soak in over night. The next morning, the glowpowder bog came out very easily. I used a dental pick to get it out of the corners and from around the base of the emitter.

The emitter is, as I suspected, working fine. The driver is shorted to the ecan, probably through the side edge of the board. It's a revision 2 badboy, I think these are the ones that had that shorting problem, aren't they?

Good work on getting the glow powder out. /ubbthreads/images/graemlins/smile.gif

How did it go?

I never got *all* of the glowpowder out, but I got enough removed to desolder the lead wires from the emitter so that I could remove the ecan. I then installed a new driver, and everything works great now with the original TWAK emitter. The inside of the head looks really messy, but you can't see any of the gunk because I put a SO17XA reflector in. Overall, I'd say it was a success.

Great job! Glad to hear that, phew /ubbthreads/images/graemlins/mpr.gif I'm sure Josey was too.