Removing Silicone Caulking

[Lew's Canoes]

A customer brought me a w/c canoe and asked me to make a few repairs, repaint and varnish, and "fix the leaks around the keel screws". A quick look confirmed my worst fear - the keel had been 'bedded' with silicone caulk. It must have been done with a shovel because there is silicone all over the keel and down the length of the hull about a half inch on either side of the keel. I got the keel off and now am wondering how best to get the silicone off, as I know no paint will ever stick to it. I have been scraping with a single edge razor blade, using coarse sandpaper, and trying other mechanical means, all with only limited success. Can anyone offer a suggestion on how to get this stuff off? Is there a solvent that will work, or any other technique? I would like to get a good coat of paint on the hull before reinstalling the keel with Dolphinite bedding compound. All help will be welcome!!! Thanks, Lew

[Chuck Hoffhine]

I have not used it but Lowe's has a product that is suppose to dissolve silicone caulk. Don't know what it would do to wood. -Chuck

[Canerodz]

The silicone caulk I've run into fails under high heat or long exposure to the sun outdoors without a covering. I would try a heat gun or a torch with a really fine tip, depending on how the surroundings will be effected by fire.

Getting the paint to stick to the area will be a real challenge. You will really need to clean all traces of silicone away with solvents/soap and may need to use a fish-eye eliminator in the paint. Sometimes shellac can be a good sealant between a hard to paint surface and paint, but I have no idea if silicone is one of those things shellac helps defeat.

Boy! I'm glad I don't have to deal with this!

Sorry. That was mean.

[Lew's Canoes]

Thought I would follow up on this topic. I found a product sold as Contractors Solvent which, as promised on the label, seems to disolve cured silicone! It comes in a hand pumped spray bottle, and promises to be very eco-friendly. Has a very citrus like smell, but still recommends good ventilation, etc. I chose to work with it outside in the breeze. The process I ended up using was first to cut away as much of the cured silicone as I could with a single edge razor blade in a holder, trying not to slice the canvas. Then I would spray on a good coating of the Contractors Solvent, let it set for 15 minutes, then start scraping, using the razor blade upright like a cabinet scraper. The solvent would cut through a certain thickness of silicone which was then easily scraped away. By repeating the process several times I was able to get the hull clean. The real test came this afternoon when I applied the first coat of paint. It seemed to bond uniformly and evenly throughout the area where the silicane had been, so I guess I can call this a success. Hope this is useful for someone else out there if you ever have to deal with silicone. LEW

[Rob Stevens]

Thanks, Lew. Sharing your experience is useful to me, although my situation is removing a pool deck carpet. I'll cut away what I can with a blade, then try eco-friendly citrus stripper. If that doesn't work, heat will likely do it, though I don't want to create acrid black smoke.

Rob