Remove baked on varnish from fiberglass

[Dasein]

I've recently purchased a very well maintained 1978 CD 25. The previous owner took good care of the boat, but unfortunately, when applying varnish to the coamings in his later years, a lot of varnish ran down onto the fiberglass (see attached picture). I am trying to figure out the best way to remove this. I've tried both mineral spirits and acetone, but both have zero effect. Some people have mentioned scraping it off, but because of the concave nature of the area, I'm concerned it may cause more damage (gouges and scratching) than do good. Does anyone have experience solving a similar issue? Thanks.

varnish.JPG

[Jim Davis]

Not a perfect solution, but one I have used. First off let me say it can be tedious and you want to go slow.

Use a single edge razor blade and gently slip it under the varnish and lift it. This gets the bulk of it off and often will leave a softer material that the acetone, etc might work on. Normally I am careful with acetone since it will often lift paints, but since you have already tried it, OK. You could also try lacquer thinner as it is easier on painted surfaces.

https://www.walmart.com/ip/Stanley-28-5 ... r/20371268 Some times using the blade alone helps in that you have better control of the angle of attack.

[tjr818]

As long as it is not on the non-skid areas, I have had some luck with careful use of a heat gun and a plastic scraper. Keep the heat low or you will melt the plastic scraper and possibly damage the fiberglass. A good stiff thumbnail works well too, but mine tires out quickly.

[Dasein]

Thank you both for your tips; I will try both tomorrow and post back results.

[Joe CD MS 300]

I have had good results using goo-off on Cetol. Just used a rag and some elbow grease. Maybe try scraping off the thicker areas first then cleaning up with a solvent. You might want to try one of the citrus based paint removers. It probably won't hurt the gel coat but test first.

[Dasein]

Thanks for all of the suggestions. I ended up doing a mixture of a few of them. In the interest of the next person facing a similar issue, here is a follow up. The varnish had been baking onto the fiberglass for at least the 5 years that she was sitting on the hard, so chemicals proved futile. I ended up using a heat gun (on the lowest setting) with a flexible metal scraper, and lightly (lightly) scraped at the varnish. A single edged razor proved difficult to use below the coping, but would certainly work in a more accessible area. Once the thickest of the varnish was removed, I used water and Extra Fine Steel Wool (Grade #000). Note the "Extra Fine" in that steel wool - http://www.homedepot.com/p/Homax-3-0-12 ... /202871994. It did not leave noticeable scratches nor change the color compared with the surrounding area. A thumbnail pressed into the steel wool also helped concentrate effort. As you can see from the follow up picture, the process worked. That's about 4 or 5 inches in the photo, and took about a half an hour. Still have quite a bit to go, but well worth it. Hope this helps someone in future. Thanks again for the suggestions.

varnish2.JPG

[Joe CD MS 300]

It's usually not a good idea to use steel wool on a. boat the minute steel particles rust and can stain pretty quickly. Copper / brass wool or Scotchbrite pads are a better option.

[Dasein]

Thanks Joe. Point taken and will be put into effect. I had read similar on another thread and had forgotten.