Dissolving Silicone Sealer?

[MEXICOWANDERER]

@#$%^&! 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 🙂 )

[MEXICOWANDERER]

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]

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]

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]

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]

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]

3M adhesive remover 08984 - available at nearly every auto parts store.

[Denny___Jami]

I have found that plain old mineral spirits works well on silicone.

Denny

[westend]

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]

Well, neither gasoline or acetone worked - at all. Soaked with each 24 hours.

The adhesive is rubbery and elastic and bonds - tight.

[RJsfishin]

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.

[MEXICOWANDERER]

Gasoline too slow.
Yesterday I purchased a gallon of Acetone and the parts have been soaking an hour.

For NERDS I have copied and below I will paste a paragraph on anodizing thermal properties by Aavid Thermaloy. Not only will anodizing protect the finish from salt air, I can bond LED chips with Arctic Silver epoxy
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



Heat sinks cooled by natural convection may benefit from an anodized finish, but the added cost of the finish may not be justified when the part is used in forced convection cooling.

Surface emissivity limits the amount of heat transfer due to radiational cooling. With 1.0 being perfect (black body) emissivity anodized aluminum is 0.85 and unfinished is 0.05.

Heat transfer due to radiation is proportional to the heat sink surface area exposed to its surroundings and to the temperature rise above ambient (in absolute °K) raised to the 4th power (T sink-Tambient)4. In natural convection on small heat sinks with open fins, and a high benefit from anodization by up to 45%.

Relatively large extrusions and those used at low temperature rise, as in many high power applications, will only gain up to 10% by the addition of an anodized surface.

With forced ventilation (using a fan) convective cooling is about 3 times higher than in natural convection. This changes the proportion of heat transfer due to radiation. An anodized finish will only add 4 -8% to the overall cooling effect in forced air. This percentage again, depends on fin spacing and heat sink dimensions. The color of the anodized finish makes little impact on emissivity since most radiational heat loss occurs at wavelengths higher than visible light.

As a thumb rule, if anodize is not required for aesthetic or corrosion protection, we suggest it only for small, open finned heat sinks in natural convection.

[MEXICOWANDERER]

Thank you all. The lens is glass. Later today I will upend them to fill via the wire trough and in goes gasoline. If for some reason that doesn't work I'll use turprntine

[gotsmart]

For Dicor lap seal and silicone caulk on the outside of my MH I have used spirit gum turpentine. It melts through silicone caulk like a hot knife through butter.

Is it appropriate for the OP's application? I would be hesitant to use it. It possibly could fog the lens - like DEET on sunglasses.

[CharlesinGA]

ernie1 wrote:
Another thing that does a pretty good job on the silicone is plain old gasoline. It seems to break down the chemical bonds and the stuff sorta falls apart in little pieces. I don't use it anymore because of the smell.

Works pretty well actually, I was going to suggest this if someone else did not.

Charles