Hit it with electronic contact spray. You’re not gonna hurt anything. The force of the spray will tend to knock off the remaining already weakened/crumbly silicone. If that doesn’t work right off the bat soak it in “Goof Off!” for 4 hours.
Then spray it again. Let dry which will be pretty fast. You should end up with just a pristine phosphor pad and its wires.
Home Depot sells CRC QD Contact Cleaner and “Goof Off!” at a good price.
Some folks use gasoline. Comparable to Goof Off! essentially. Just a lot more vapor-flammable.
The stuff ya mention could be too harsh.
Ya know I’ve never tried kerosene which is relatively mild. I’ll give it a shot someday.
The contact cleaner should be fast drying and leaves zero residue. Essential in the process.
I use brake cleaner when cleaning dirty emitters and flashlight parts. Contact cleaner works also. Brake cleaner is effective when removing excess soldering residues from pcb’s.
It may work butt it can also harm certain plastic finishes and coatings. It’s a gamble. That’s why they use it on not so delicate brakes and not delicate electronic components. Contact spray is safest, less toxic, and much easier to deal with if it gets on ya or yer clothing - stink wise.
I think brake cleaner to clean dirty emitters and associated parts is kinda well, plain
overkill. :laughing: :confounded: 
Well, that might be. I think they are chemically quite close. They even smell the same and both evaporate very fast.
I checked from my spray bottles, so that I don’t spread false information. Brake cleaner and Electric cleaner both have kerosene as a base component. Brake cleaner also has small amount of acetone and benzol. Less than 1%.
Regarding break cleaner… be aware in the US there are green and red cans. The green, if I remember correctly, is non-chlorinated and the red is chlorinated. The red is the one that you need to worry about around plastics, but it is a much better solvent. I use both on firearms and only green on lights and electronics. I have see the red make plastic gummy and change colors.
Bottom line is that if the spray yer using doesn’t say, “Safe for Plastics”, yer gambling. High quality electronic contact sprays will typically say that. And I don’t care watt anybody sez, electronic contact sprays tend to evaporate faster and leave no residues. Evaporating faster means ya also have less of a chance shorting something out cuz ya got impatient to fire things up.
I’d have to be pretty dam hard up to use brake cleaner on an emitter or PCB that’ s fer sure. :laughing:
Have contact spray From CRC but don’t evaporate.Maybe not right for dedoming
I use it on switchs and contact points to avoid oxidation and increase cross current,it work well.
For this Led I’ll try again petroleum for lighters.
For dedome SSt-20 what about Acetone? Should be more aggressive,so maybe less time to wait.
No problem. I just told my own experience. No one has to do as I do.
Huh? CRC QD Contact Cleaner doesn’t evaporate? News to me. :person_facepalming:
It evaporates. Maybe not the absolute fastest butt it evaporates plenty fast enuff.
The fastest evaporative contact cleaner I almost exclusively use is, Puretronics Contact Cleaner. Stock No. 3500. Relatively cheap yet absolutely fantastic stuff. :+1: :+1: :+1: :+1: :+1: :student:
One other tip: Take a can of compressed air, hold the can only horizontally, and after ya spray the contact cleaner over your partially dedomed led, give it a blast or two of air.
This will clear out tiny particles of dome material from the phosphor and any remaining contact spray will get blown out too. :+1: :student:
My CRC it’s another old product called “electro”.Not a specific contact cleaner as you said and guarented doesn’t evaporate,infact he still where I had applied
But I”ll try also your method
Some contact cleaners have a light oil in it to a) act as a lube and b) lightly coat the contacts to prevent corrosion/oxidation.
Dunno from that particular brand.
Finally I can use my chemistry degree. The base of an LED should be ceramic. The dome should be clear epoxy or clear epoxy with bismaleimide-based polymers added for strength and heat resistance. The Phosphorus is probably vapor deposited with Silicon “the element, not the gooey stuff” I’d say some of the harshest solvents out there should be fine. Of course I’ve been out of a lab for 27+ years.
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.
Looks great in orange though!
Did you drill out a reflector for this or find one somewhere?
I used lathe and centerdrill.
It is little bit darker, so I finally took beamshot of S21A with GT-FC40 4000-4500K led. Distance is about 3 meters.
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.
Gasoline, AcMe, MEK, etc., all work fine without eating at the phosphors.
Hard to get the stank of gasoline out if you use that, though.