Fiberglass over a painted area

[wan2live]

I have a restore thread goign but hope to get a fast response to this 1 question.

I replaced a portion of the wood in the jump seat area and I painted it with an epoxy based paint to seal it, I was reading the sticky on fiberglassing and it looks like the wood should be bare when FB'g ? do i need to sand all of the paint off (2 coats) or will the resin cure ok? also I bought Resin and cloth and was reading that I would need epoxy to joint the new FB to the old where I had to cut out the area to be fixed, do I need to epoxy the edges to join them correctly and resin the rest?

Thanks all!

 

[drewpster]

Re: Fiberglass over a painted area

It depends on the paint. Personally I would strip it off unless I was certain it could hold up to the solvents in the resin.
Epoxy is better at bonding things together than polyester resin. Polyester resin is less expensive and works well as a coating along with cloth, roving or mat.
I would use epoxy if the repair depended on a strong glue bond. I would use polyester resin if the repair depended on building up and sealing a surface.
It is not a good idea to use polyester resin alone. Always use some sort of reinforcement (fiberglass) when using poly resin.
Epoxy is stronger, and it is ok to use it by itself as a coating or glue. If you need to build a surface up with epoxy, cloth is generally used with it.

It all depends on the kind of joint you are working with. If you are filling a square hole with a square piece of wood. I would hold the patch in place with stainless screws just enough to hold it. Then I would tape around the edges using strips of glass and resin, then glass over the whole thing. (butt joint)

If you are bonding a piece of wood over a hole. (lap joint) I would glue it down using epoxy then glass over it to seal it.

Generall speaking, if I were making a repair over an existing deck I would use all epoxy products and cloth. If I were starting from scratch or making a large repair with new wood I would use polyester.

hope this helps
drewp

 

[ondarvr]

Re: Fiberglass over a painted area

All of the paint needs to be removed, if the paint was made from actual two part epoxy (just tinted) it might be OK, but single part "epoxy" paints are just using the name, they have little in common with a true epoxy. Paint is just a contaminate on the surface when it comes to using either type of resin.

 

[wan2live]

Re: Fiberglass over a painted area

Thanks guy's looks like it is a day of sanding for me :-(

I am doing part 2 of your answer drewpster I removed a 14 x 10 piece of the floor under the "right" if you are in the boat loooking backs jump seat, I sealed it using spray in foam, laid the wood on top, put 2 batteried on top to press it into place and screwed it down in a few places.

I purchased the resin and the cloth yesterday so part 2 of your post is what I was looking to do.

Thanks I'll post photos.