How do I easily remove silicone sealant?

[Axtman]

I need to remove some power supply capacitors from a pcb. Unfortunately they have been glued down and around with silicone sealant. Is there a chemical that will soften or dissolve the silicone goop? Thanks!

[Enzo]

Nah, just slit it with an Xacto blade.

[Mark Black]

Howdy -

I have had pretty good luck with Ronsonol Lighter Fluid (Naptha) and a stainless steel brush after removing the majority of the stuff with an Xacto or similar. The Naptha kind of "jellies" the silicone sealant, letting it be easily scraped off by the brush bristles.

[drewl]

Razor blade to remove component as Enzo said, denatured alcohol to get it off components or a heat gun. A hair dryer should work if you don't have a heat gun.

[Axtman]

Thanks for the suggestions. Unfortunately the large capacitor I am trying to remove is very well glued down......almost like it was a structural component!

An amp repair buddy of mine told me that he rarely uses "component goop". But when he does he uses a hot glue gun. One of the reasons is that he can more easily remove the component afterwards if the need arises. He just reheats the component to soften the glue. Also hot glue takes little time to cool, minutes instead of hours with silicone sealant. The disadvantage I can see is using the hot glue on temperature sensitive components.

[Gaz]

[QUOTE=Axtman;305035]Thanks for the suggestions. Unfortunately the large capacitor I am trying to remove is very well glued down......almost like it was a structural component!

An amp repair buddy of mine Pick up Tolex from Jeff]

Unfortunately hot glue is not very reliable. I've seen amps where the hot glue has unglued itself, seemingly without much trouble. Ive never had good luck with it myself, including the nicer stuff. Silicone is a necessary evil sometimes in hand wired stuff, and it seems stand the test of time (plus it sticks to metal). Zip ties can be a good alternative if the construction allows them. Something is better than nothing though - I've seen snapped leads on heavier components (usually axial caps) causing big trouble! I would never use a two-part epoxy however - too messy and impossible to remove unles of course there's a Dumble underneath

[gbono]

3M General Purpose Adhesive Cleaner, bug and tar remover, adhesive remover, tree sap remover

This product will remove the residue of RTV, silicone adhesive, etc, though I've never used it to dissolve large amounts.

[drewl]

A heat gun would melt and soften the glue so it can be removed.
My solder station has a hot air tool with a nozzle for directing the heat which makes it easy to remove glue.
Or take your soldering iron, melt the glue and remove.
The problem with that is you will have to clean the tip very well, but it works.

[Mick Bailey]

The hot melt glue used in amps is pretty useless stuff. You can nearly always cleanly pick it off. I've just rebuilt a motor controller that had hot melt on everything and that stuff was really stuck. When I melted it at a surprisingly low temperature I couldn't believe how sticky it was. No chance of getting it off skin. Worse than superglue. A real pain to remove from wiring and components.

The crap stuff on amps does us a favour when we come to do a repair.

Removing silicone from a big cap can be a problem because you've only got the thickness of the silicone layer to work on, not the area. Most products that break down silicone are intended to be spread over the surface and not penetrate sideways through the material.

I once desoldered a large cap and attempted to rock it backwards and forwards to break the silicone. It came away with part of the track stuck to it - double sided board, so two faults for the price of one. Nowadays with large stuck-down caps I slice through the silicone using either dental floss or an .008 guitar string, as well as lighter fluid. I don't get many like this, though.

Another trick I've used with caps in WAudio PA amps is to score through the cap shrink wrap and pull the body of the cap out of it's skin. They stick 'em down on the edge of the can. Remember to desolder it first, though. Then you can attack what's left on the board.

[Prairie Dawg]

What I do is I take a razor blade or exacto knife, slice open the plastic wrapper on the cap, clip the leads and artfully toss it in the trash. Then, a good tug with a pair of pliers removes the silicone sealer. A cleanup with a scraper of some kind and Bob's yer uncle. Don't scrape the traces, though.

[Gtr_tech]

I don't recommend silicone to hold down components unless its electronics grade (acid free).

I use this stuff for teh job and it works great, won't outgas to harm components, and its readily available at any wally world near you.

Loctite 212220 2-Ounce Tube Stik 'n Seal Indoor Adhesive - Amazon.com

Note: There are 2 different varieties of the stuff, you want the *indoor* version. The outdoor is more of a contact cement...not what we need here.

[Enzo]

Drewl, I think you are confusing silicone with hot melt. Nothing alike at all.