Inspired by this discussion about chemicals and dedoming I did few tests. I put WD40 and brakecleaner in small container. Those small plastic cases that Simon uses when he sends emitters.
I put sliced Xhp70.2’s in both of them. WD40 hardly did anything in 24 hours but brake cleaner did this in 10 hours:
Seems promising. Let’s keep experimenting. (Grey stuff is just leftover thermal paste)
After testing the emitter works fine. Sadly this one has had some strange behaviour before, and after this harsh bath it hasn’t improved. 1 of 4 diodes is cooler colored than the others and it also has afterglow for a few seconds. It’s like 5000-6000K and others are 4000K as they are supposed to be. It also lits up in lower voltages than other 3.
If you do a search on “dedome” in BLF, you will get lots of interesting and informative posts. Brave members experimenting with different methods!
Here’s one example: 100% Perfect dedome method
Not sure if there is the best liquid that works for all LEDs since manufacturers all make their LEDs differently.
On the subject of aromatic solvents, does anyone know of an epoxy (the cured hard type) solvent?
Have a very small amount to remove from a watch mechanism. Can’t scrape this off and immersion of the whole spring/ escapement is not an option. But I could wrap it in some gauze and light plastic film to let it do its thing.
Tried Methyl Ethyl Ketone (MEK), Acetone (diMethyl Ketone), Methylene Chloride (Acrylic solvent / one of the ingredients of paint stripper).
Google search – bad results; easy to remove uncured resin. Nothing really tested about cured stuff. I mean, isopropyl, methyl or ethyl alcohol, paint thinner (usually kerosene), lacquer thinner (which is mostly MEK but some variants having more volatiles), and citrus-based cleaners as GooGone just makes an oily mess. No success on some test pieces.
Hadn’t tried gasoline – smelly, although very active solvent.
Methylene chloride for Epoxy. 5% sulfuric acid or sodium hydroxide for polyester resin. Dichloromethane warmed to 40C for a few hours. Methyl Ethyl Ketone (MEK) I used for removing cured epoxy on pcb’s. It’s the same chemical your Kidney’s release that make that awful morning piss smell.
Ketone solvents including Nitro thinner should give cleanest and fastest result with less tint shift.
I have some old xp-e to be sacriced
Cree leds can be dedomed with anything, but I will be all ears if good results are reported with Luminus leds.
.
Please let me know your method.
Tried non chemichal way on LB led,pre heating and blade.
The dome come out but also phospors :person_facepalming:
I tried Methylene Chloride but was disappointed. In no way dissolved the Epoxy.
H2SO4 or NaOH can’t use on precision watch parts - substrate of aluminium and/or brass.
MEK has no effect on my test pieces.
Dichloromethane is Methylene Chloride. This boils at 39.6ºC.
Now if you soften the cured epoxy with these products and then scrap them off, perhaps. But I’m looking for a solvent.
So maybe the solvents aren’t what is written on their containers or my chemistry is wrong. The Methylene Chloride is clearly labelled as such, IIRC. Used for acrylic fusion from a plastic modelling company. The MEK is a principal ingredient in lacquer thinner (from the can label as MSDS – commercial packaging).
I always thought Uric acid was the nasty morning pee smell.
Simply swap led in Trustfire T4, days ago. Put cslnm1.tg in it but the result is worse than I expected. Seems like the reflector is not suit for this led, the beam lost too much light to corona around hotspot.
I tried to upload pics on Imgure all day but still can’t until now. I will post it later if Imgure let me upload them.
I might try to change led again later to a more floody higher lumen led .
O K. I uploaded them.
Seconded.
You’re right it does boil at 39.6 It’s been awhile since I’ve used it. However I did use it in a glass jar with a loose lid swirling it while in warm water. It kept the smell down. Fume hood only goes so far.
Google says excessive uric acid has an ammonia smell, myself I don’t remember. Eat too much fat the night before and you’ll get a little more MEK out in the morning. All the stuff I used I’m surprised I don’t have cancer. You harsh chemical users; Fume hood or outdoors not garage style but really outside. Gloves, splash guard, cotton clothes.
@texas shooter:
But I still don’t understand why my methylene chloride doesn’t dissolve the hardened epoxy. It’s one of the active ingredients in paint stripper (along with sodium/potassium hydroxide – the gel types). And the smell is ethereal - almost sweet.
I’ll be trying gasoline. It’s loaded with petroleum esters and although has a lingering smell, is about my last resort.
There would be some “Lepage’s glue remover” which I doubt is sold in the US. But typically these over-the-shelf concoctions are a random mix of many VOCs (volatile organic compounds) and leave many residues.
Wellp, most epoxy is kinda by design not supposed to melt or dissolve, but I’ve seen (but haven’t really tried) using IPA and/or AcMe to loosen/dissolve it.
Try it? Both are easy enough to get even at a CVS or whatnot. “Rubbing alcohol” and “nail-polish remover”.
If ya can’t get it locally order online: Goof Off!
Works well on most domes. Soak overnight.
Less flammable/explosive vapor-wise. And it doesn’t leave a lingering smell on anything including fingers. Gasoline tends to. 
PS. After dedoming always spray it off with No Residue contact cleaner.
I attempted to open a broken Zebralight today.
I couldn’t even get the lens retaining ring off. I wasn’t able to wedge anything under it. I suspect if I want to mod one of these, I’ll have to shatter the lens, pick out the pieces, and only then be able to lever up the ring with a screwdriver.
Thanks all. As I originally posted, IPA and acetone have no effect.
And to LB for honestly saying he never tried those. Too many false positives about the web. There is a difference between loosening and dissolving. IPA is so mild, wouldn’t make a smear in grandma’s diapers. Acetone, very polar and volatile, doesn’t attack closed chained polymers. or most esters but for a smidge of hazing the surface because of the reaction’s oils that mitigate to the surface.
GoofOff is citrus-based oil and would not be suitable for such a delicate mechanism. I’ve once used that stuff with poor results and a mess to clean, which I’ll always never use from now on. It’s too tame and lame.
Would there not be someone with experience with esters (some chemist) on the forum?
edit;
And please don’t chime in ‘brake cleaner’ (perchloroethylene, aka PERC - dry cleaning fluid).
If you feel uncomfortable with these aromatics, don’t suppose others are as such. I’ve worked with much more “reactive” chemicals including Perchloric Acid and Antimony Pentafluoride. So none of these ‘mommy’ scares about cancer or flamability.
I modified an Xbox One controller’s cool white LED to amber. I was using an old Xbox 360 controller for a long while. It had green emitters. It wasn’t until the joystick on my old controller started to stick that I really had to look into using the newer controller. I didn’t like the use of cool white backlighting, especially at night. It’s a good feeling experience to have a light I use so much shift to low glare amber.
Also wanted to mention, I had initially planned on using warm white 2700K, but the footprint of the planned Osram emitter wasn’t working with the PCB footprints.
Yeh, that was straight from the Loctite site, among others.
Don’t the 2-part epoxies use “lock’n’key” molecules to polymerise? That makes ’em especially tough to chemically split apart again.
My reaction (haha) to the Loctite page was “IPA? Nfw!”.
So yeah, I only tossed it out there as untested.
Sydney Stratton….
Lemme get this properly straight. Yer trying to dissolve a CURED surface-hardened epoxy without conceivably fooking up watt’s underneath. Good luck. I think you may be going to a powerful acid cuz that’s about the only type of chemical AFAIK with that kind of penetrative “bite”.
As for Goof Off! it may be relatively tame butt as for most dedoming it’s certainly not lame.
Don’t know watt ya messed up by using it. Curious as to watt it was though.
