@#$%^&! lights. Glass Fresnel dome lens. Countersunk into aluminum housing. No way to do a tight 90 degrees (1/32") with a knife.I need to DISSOLVE the blue silicone sealant someone so unwisely sealed the lens with. It's a counter-clockwise turn to unlatch the lens from the aluminum housing.Something hands-on proven to dissolve or make junk-gummy the silicone sealant.I can pour liquid through a tiny (wire-entry) channel and into the chip chamber. The chip is about 20% of the wattage I want out of these turkeys so if the chemical eats the LED, T.S.What's been (hand's-on-experience) proven to work? If it takes a week to dissolve the snot too bad - it's better than nothing.And yes, it's worth it. The lamps cost almost $400 ea. new. They're going to get a kick-in-the-butt lumen output, wise.(I'm heading to the barn until mid-morning, Monday :) )

Dissolve cured silicone? There's nothing off the shelf you'll find.What's the rest of the lamp made out of, any plastic parts? I think heat would be your best tool of attack, not all silicones are designed for high temperature, you might melt it or soften its grip enough that it lets you remove the lens.Silicone caulk is a polymer chain of silicon and oxygen with some proprietary magic compounds thrown in for good measure. Those elements are pretty darn durable.The great Google reveals a witches brew of xylene, toluene, sulphuric acid and other dandy compounds... chemicals that I would not want to mess with.

In my young and broke days, I had a radiator leak in my 71 Camaro.I had no money but I did have a partial tube of silicone. It actually worked! It never leaked again, and that was in Phoenix AZ where it gets HOT!. I sold that car years later to my younger brother who ran it a few more years till it caught fire and burned up... But that radiator was then sold when he parted the car out... For all I know, it may still be working fine in another car.

No personal experience here, but I've read comments elsewhere that acetone will clean up the gummy residue of silicone. So if you fill the thing with acetone, I'd guess it could loosen the bond enough to let you unscrew the lens and then scrape off the rest of the bead. Other folks have used De-Solv-It, contractor grade version. Of course, I don't know if the solvent would mess up the lens.

Hrmm, I looked up the MSDS for De Solv It "Contractor Grade". It contains petroleum distillates (a light oil) and ether (organic solvent). It's not going to touch cured silicone, but it might get into the space between the silicone and the aluminum housing, loosening the grip enough to break it free.Could try a generous application of WD-40 or other penetrating oil of your choosing.

I might be temped to try baking soda blasting to abrade the silicone away. I think baking soda would be sufficiently gentle to be unlikely to cloud glass, though it might attack plastic if that's what the housing is made of. Then again, if plastic, most any chemical (and there really isn't much) that would attack silicone would most likely attack the plastic too.

Dissolving Silicone Sealer? | Good Sam Community

MEXICOWANDERER
Explorer
Sep 23, 2016
Eeeeeee...

Fresnel Pyrex lens, we avoid smashing. I can just imagine contacting CREE and inquiring about their adhesive Xi, Xi, Xi, Xi. I can just imagine their laughter.
Harvey51
Explorer
Sep 23, 2016
Interesting! In 1975 I had a similar problem in a university physics lab where I was doing a laser project and inherited a UV laser made from two aluminum "boards" about about 6 feet long with groves milled into them for two pieces of quarter inch glass, and chrome plated bandsaw blades for electrodes, which had corroded. Of course it was siliconed together, vaxuum tight. After trying a few things I called the silicone manufacturer and was told there was no solvent for silicone. I smashed the glass.
MrWizard
Moderator
Sep 23, 2016
Seems like it is some brand of polyurethane sealant
Aka 3M, divorce, etc..
The 3M remover might be the only option for a liquid softener
MEXICOWANDERER
Explorer
Sep 23, 2016
Even though the substance is rubbery, elastic and gray (Grey for BFL13) 3-days submerged in acetone did not touch it. I'm beginning to think it may be DiCor or Dow Corning 5200. At risk of staining the aluminum and compromising the upcoming black anodizing, the only path left is to use a torch and thermally decompose the adhesive. That being the case - the heck with it, they're getting 100-watt chips and waterproof drivers.

Thanks for the suggestions! You all, and I both were working in the dark and I appreciate folks taking time to help.
luckyd
Explorer
Sep 23, 2016
I wanted to replace the silicone in a shower.
I sprayed WD40 on the silicone, waited about 30
minutes and it came off very easy.
Chris_Bryant
Explorer II
Sep 23, 2016
3M adhesive remover 08984 - available at nearly every auto parts store.
Denny___Jami
Explorer
Sep 23, 2016
I have found that plain old mineral spirits works well on silicone.

Denny
westend
Explorer
Sep 23, 2016
MEXICOWANDERER wrote:
Well, neither gasoline or acetone worked - at all. Soaked with each 24 hours.

The adhesive is rubbery and elastic and bonds - tight.
Latex?
MEXICOWANDERER
Explorer
Sep 22, 2016
Well, neither gasoline or acetone worked - at all. Soaked with each 24 hours.

The adhesive is rubbery and elastic and bonds - tight.
RJsfishin
Explorer
Sep 22, 2016
Well well, there are a few here that know what their talking about.
Yes, from actual experience, simple gasoline will remove sillycone. A good Laquer thinner does it faster, and acetone works better yet. No guarantees as to damaging plastic.

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