Some datasheets mention the materials used, Nichia’s for example and the dome is made of silicone, Cree presentation about dome and domeless LEDs mentions it too.
Then have at it, the silicone should easily be removed with harsh chemicals without harming the substrata. Less harsh try Vinegar and isopropyl alcohol with good long soaks.
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.
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.
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.