If it’s not really dark, then logically one avoids more ‘light pollution’ in the form of fat beam and spill. So there’s another use for a skinny thrower. 
Anyone ever try a silicon digestant like Dow Corning DS-2025?
I have some on order. I’m looking forward to seeing how well it performs. Seems like this stuff would effect the perfect de-dome: unlike solvents, digestants leave no traces of silicone.
There's only a residue left after using gasoline if you choose not to flick it off with a toothpick. No matter how many times you try to reinvent the wheel the end product is still gonna be something round that rotates around a central axis. Gas works, is readily available even in parts of the world that don't have indoor plumbing, doesn't have to be ordered from some specialty supplier, and won't harm the LED.
Mfrey…
I think all should stick to gasoline. After gasoline bath use Isoproply alcohol splash cleanup and surface is clean as it never been de-domed after all.
Stick to verified things.
You should all read this funny post in this thread. This was hilarious to me 
It has deep message. It is about different ways of de-doming. I will quote it:
“There may be an even better way. All you have to do is build a rocket to launch the LED to fly close to the sun to heat up the dome, then a super-intelligent robot can poke it with a pin and peel the dome off. Do you think that might work better than just dunking the damn thing in gasoline and then a few hours later like magic you have a freshly de-domed LED?”
I’m going to try it. Worst case scenario, I’m out $5. I think it’s going to work beautifully.
Hey Mfrey,
I was apprehensive about using petrol (gasoline) to do any dedome work.
I’ve dedomed 6 emitters, with only 1 failure, and even then, it wasn’t down to the gas, it was down to two gold wires coming away with the dome, and it was a difficult XR-E emitter with the small metal ring anyways, and I’d hung the emitter upside down in the ‘dedome tank’ (a small jar for making home made jam), so when the dome fell away and took all the ‘goo’ from underneath….the wires fell away too. I suspect a sub-standard, or even a counterfeit Cree emitter quite frankly!
I’ve even dedomed an XP-E………tiny thing it is, turned a Small Sun ZY-C10S into a laser!
Just grow a pair and do it! I used a razor blade to score the domes several times, it speed up the process.
To clean, I use a 35mm film roll canister, filled halfway with methylated spirits, don’t know what it’s called over in the States, and swirled the stars for a few minutes, then I used, well, an old tshirt cut into squares, I can feel the emitter edges better you see, I removed the excess spirits, then I use a hairdryer, set at cool, at around 30cm away from the star, and blow dry it for a few minutes on high speed.
No gas smell, and a nice clean, bright star!
Hope this helps my friend.
Rob
I have used gas and it works pretty well. I agree. I’m trying the DS as an experiment. I won’t belabor the point but this stuff was formulated to do exactly what we want a solvent to do for de-doming: quickly and completely remove cured silicone without otherwise damaging the substrate. It even washes off with water when it’s done.
I was going to post results afterwards but folks seem resistant to something new, so anyway…
I don't think anybody here is resistant to anything just because it's new. Personally I'm resistant to things that don't work as well or aren't as convenient. If this DS were available at every corner store in the world and cheaper than gasoline I'd be all over it.
Say someone proposed switching all road vehicles over to square wheels, and had proof that they work just as well as round wheels as long as you cut all the roads with the appropriate washboard pattern so the ride is as smooth as with current-tech tires, and maybe they even give better traction as long as the wheels & road surface stay in phase. Better road-holding, fewer traffic fatalities. That would be something new, right? Would it be silly to point out the shortcomings of square wheels?
Well, I am curious about anything new, useful and not so usefull the like, so I'd be glad if you try out the silicone solvant and post about the results :-) (I'd also like reading that post about experiences with square wheels and zigzagged highways ;-) )
Please, let us know the results!! This is exactly part of what BLF is about - experimentation, R&D to find better solutions. At the time, I thought gas was the best easiest way, that's why I started this thread, but records are made to be broken.
thanks comfy! :-) :beer:
Hope you post the results, mfrey!
I’ve decided to try dedoming one more time after one unsuccessful attempt. Took the pill out of a Defiant 2AA and hung it upside down in a tiny container of gas (actually, the cap to the gas can). That was 14 hours ago, better go check on it…it might have evaporated!
It's been posted LED's have been left for several days in gas with no known side effects, so should be fine. I try to do 2 - 2.5 hours, but frequently let is soak overnight, sometimes to the next evening, so 24 hrs has been no problem with me.
Just checked…most of the dome came off with some residual left…but the gas had evaporated who knows how long ago. Put some more gas in there to soak off the leftovers.
And thanks, mfrey, that DS-2025 looks like it was made for dedoming. Let us know what happens!
Thanks comfychair, your square wheel vid reminds me of driving through East Los Angeles …
Well the Defiant 2AA light was a semi-successful dedome. It came off but the light it puts out in VERY blue. However, it still works!
Buoyed by the sweet scent of near-accomplishment (and LOTS of gasoline smell) I decided to dedome my S5 Convoy w/XML U2 1B emitter. After slicing into the dome then soaking in gas for 4 hours the dome fell off with just a touch from my fingernail. Next it went into a bath of rubbing alcohol for a while with some swishing around mixed in there for good measure. Then it hung by a ziptie to dry for an hour or so. Before pushing it back into the pill I put some Fujik-like white stuff behind the board…probably way too much, it came out around the edge and made a bit of a mess!
Anyway, after reassembly the darned thing WORKed! The beam was much warmer in color and narrower, with a tiny bit of a donut shape to the hotspot. Upon ‘testing’, which involved visually comparing it to another S5 that has the same 2.8A driver and an XML2 U2 1B in it, it doesn’t seem to throw any farther and puts out noticeably less lumens.
Any ideas on how to improve it from here? I assume the presence of the donut means the focus is a bit off…how should I attempt to rectify this? It has a SMO reflector in it. I’m a little disappointed that it didn’t do much for the throw, I knew it would lose some lumens and warm the beam tint up a bit. I tried spacing the emitter back a little and it didn’t seem to help.
Thanks to Tom E. and everyone else who has posted their results here!
The transition to blue is strange - seems like the phosphor came off - that's what the beam tint will turn when that's happened to me on XML's.
Usualy the donut hole (I assume dark center?) is from the emitter being further out of the reflector, so you need to get it further in, I believe??