The answer may have been under my nose this whole time (some pun intended there). I’ve been using a solvent called Wil-Bond made by imperial. I don’t recall ever trying to do a full chemical dedome with it for fear of phosphor damage and generally I’m impatient. BUT - I have used it with much success to clean up the bits left behind during my hot dedomes and it seems to make quick work of the silicone scraps. So I looked up the MSDS and compared it to the solvent list I’d linked previously… What I found is that it’s full of theoretically effective solvents. I will say it’s odor is definitely nothing to be taken lightly. Even the can sealed up and in a cupboard, I can smell it on hot days when I walk into my hobby room. The good news is it can be found in the US at Walmart and has free shipping for ~$18
I’ll throw a few sacrificial LEDs in there tonight sometime and see what happens. I don’t think I’ll try heating it at all. Don’t have the appropriate space or heating equipment for that right now.
Update on previous post:
(only relevant to Dutch dedomers)
It’s a little confusing…
This “ELMA thinner” is sold as ‘thinner-tolueen’ but it doesn’t say ‘tolueen’ anywhere on the bottle, not even in the ‘samenstelling’ (contents).
However, after asking ELMA themselves they assured me there is tolueen in it.
They promised to send me a more detailed list of ingredients.
I will report back on this here.
Been testing White Spirit on an old XM-L and newer XM-L2s, a little bath and 3 to 4 days to soften and remove leftovers; does a pretty good job. If in a hurry, bain-marie.
Tried one more time and this time without heating the Toluene. It took a long time to get the dome completely clean. But it was totally worth it! For the first time there was not a single hint of green in the tint!
I will post a beamshot later showing this sst-40 against the one done in Nitro thinner.
Sledgestone, in order for camera pictures be worth comparing chromaticity wise, a common reference point must be used (usually “daylight” or 6500K). If “auto” is used the device will try to detect and compensate the spectra for it to look like daylight, usually with bad results with some sources but good with others (hardware and software dependent too, of course).
The pics look good to me, at least with regards to differentiating the dedoming process turn outs.
I used to soak my LED’s in “wasbenzine”, what translates into: white-spirit; refined petrol; cleaning spirit; cleaning fluid; dry-cleaning naphta. Confused? Not really, the chemical compounds involved are seldom identical from brand to brand. Last time it took 48 hours, and I still managed to tear off the bond wires when removing the residue.
So I ordered some MEK (methyl ethyl keton) and the dome of the SST-40 came off in 2 hours, and much cleaner.
I was swapping an emitter in a bike light and one of the XP mcpcb boards I was modding I slipped while cutting with a small wheel.
long story short (after I picked it up from dropping it) it had yielded a perfectly shiny silver emitter surface that when turned on at way under driven amounts, was the most even mule of “angry blue” I had even seen. I cant even guess and what color it would have been called. 000A or light royal blue.
But just so you know if you ever need a high power blue you can start with normal yellow.
Suggestions for reasonably priced protective coating for de-domed emitters? I only tried once so far (warm gas soak with no apparent loss of phosphor) and came close to success but my hand twitched while picking off a bit of residue near a bond wire… will try again but want to have a suitable sealer here before doing so.
White LEDs are just monochromatic blue LEDs that’re coated with a mixture of phosphors that emit green, yellow, red, etc. when excited by shorter-wavelength (ie, blue) light.
Less phosphor means more blue light gets out unimpeded and less blue light gets reradiated as warmer colors, hence “cool” white.
More phosphor means less blue light gets out unimpeded and more blue light gets reradiated as warmer colors, hence “warm” white.
There’s a conversion loss from blue to other colors, which is why warmer-white LEDs are less efficient than cooler-white LEDs.
Sounds like you just shaved off all the phosphors and left the nekkid blue LED undamaged.
Thanks. I’ve never ordered from that vendor but the price is better than I saw elsewhere. Still curious if there are any tested alternatives. For example, I’ve been wondering if a uv curing clearcoat scratch repair liquid might work. Cars parked under direct sinlight get pretty hot and the material would have to deal with the temperatures associated.
Pretty good. Decent prices, fast shipping, no complaints at all.
Miller-Stephenson (in Connecticut) sells all sorts of conformal coatings, including silicone! Ie, pull off the dome, but with thinned silicone, a thinthinthin coating can protect the nekkid chip, but still be less of a coating than a shaved LED.
Silicone, urethane, you name it. Something like 5-6 different kinds.
You can get ’em in a spray-can or also in bottles, last I recall. Quick spritz onto a disposable surface, finefinefine brush (forgot what they’re called, “baby-hair” or something weird like that) to apply right to the surface of the chip.
