How to remove paint from fiberglass floor?

[simpleinterest]

I have 14 foot sailboat with a large soft spot on the port side. We removed the inner skin and found that the 1/8 in coring was rotten, causing delamination. We have removed the coring and since the layer is so thin, we plan to do the whole repair using glass. We're almost ready to start laying glass, but need to remove the paint surrounding the cut, to promote adhesion. We plan to overlap the fiberglass.

As you can see from the photo, I've sanded down all of the high spots and the remaining paint is stuck in the weave of the fiberglass cloth.

How best to remove this paint? Options are:

1. Chemical Stripper.
2. Continue sanding through the fiberglass until all paint is removed.
3. Fiberglass over it.... hope that the fiberglass sticks to the paint.
4. ???????

 

[jigngrub]

Option #2 will be your best solution, you're going to build it back up when you lay the new glass anyway.

When a boat develops soft spots the rot usually extends far beyond the soft area both horizontally and vertically. I suggest further investigation to assess the full extent of the rot problem. Fiberglass boats rot from the inside out and the bottom up.

 

[proshadetree]

With that thick of a weave I think at the edges you will be laying up over some of the paint deep in the cloth. If you have beveled your repair the main cloth you will replace will be in clean fiberglass. You will sand away the edges for a second lay up. As far as will fiberglass sticking to paint look at the many repairs on automobiles. You are going for a mechanical bond not a chemical one anyway. If the paint just will not let lose I don't think you will have an issue. Going to get some crud for that one, but it's my opinion anyway

 

[gm280]

Okay here is just my 0.02 cents worth. IF you can wipe over the little remaining paint/gelcoat/whatever in the shallow areas of the heavy glass weave with lacquer thinner or acetone and it doesn't phase it one bit, then I would glass over it. There is enough tooth there for the mechanical bond with your new glass works. Yes you equally could keep grinding to remove every little bit of paint or whatever, but why? Doing that takes away from the structure thickness and won't add any benefit in the scheme of things. You could even try a brass wire brush on a drill to see if that would remove the paint. But again you could do more harm then good. But that is just my uneducated opinion. Certainly not even close to a pro...

 

[Woodonglass]

Are you certain it's Paint? Have you applied a solvent to it to see if it's affected? It might be Gelcoat and if so then no further prep other than sanding and wiping down with Acetone would be required. If in fact it is paint and with that large of a weave using Polyester resin could be problematic with adhesion. You might be better served using epoxy and then painting over it. That's my 2 cents.