Fibreglass Repair near door

[eldame]

Hello all. I am having trouble finding answers as to how to do some repair near the door of our ‘73 Boler. I searched through Fibreglass Dave’s posts but couldn’t find for sure how to proceed. Any advice?

[John in Michigan]

It looks like the top layer is paint, not gelcoat. Looks like possibly an old repair that has disintegrated. The original fabrication would have been chopped fiberglass embedded in polyester resin, with a top layer of gelcoat (pigmented polyester resin).

Again it looks like an old repair that's coming apart, with an outer paint layer. Also, and this is important, the repair might have been epoxy, not polyester. Because polyester resin does not adhere well to epoxy resin, its best to do your repair with epoxy resin and hardener. Just grind what you want removed down to fiberglass OR solid epoxy base, sand, clean with acetone or denatured alcohol, then build it back up to establish the original shape.

You'll need to use thickened epoxy. A small quantity of thickened epoxy such as sold by Marine Tex, PC-7, or JB Weld will work.

EDIT: ... then apply matching paint.

[John in Michigan]

On the other hand if you think its still all original gelcoat top layer and chopped fiberglass embedded in polyester resin, then you can grind or sand 80 grit to a beveled edge, then fill with thickened polyester resin and chopped glass, then fair with thickened polyester resin, then top coat with either matching gelcoat or paint.

[eldame]

Originally Posted by John in Michigan

It looks like the top layer is paint, not gelcoat. Looks like possibly an old repair that has disintegrated. The original fabrication would have been chopped fiberglass embedded in polyester resin, with a top layer of gelcoat (pigmented polyester resin).

Again it looks like an old repair that's coming apart, with an outer paint layer. Also, and this is important, the repair might have been epoxy, not polyester. Because polyester resin does not adhere well to epoxy resin, its best to do your repair with epoxy resin and hardener. Just grind what you want removed down to fiberglass OR solid epoxy base, sand, clean with acetone or denatured alcohol, then build it back up to establish the original shape.

You'll need to use thickened epoxy. A small quantity of thickened epoxy such as sold by Marine Tex, PC-7, or JB Weld will work.

EDIT: ... then apply matching paint.

thanks John. We bought it a couple years ago - we are third owners. From what I understand it is still original paint, but I could be wrong. Notice the cracks heading up from that spot up under the door flashing. The door was really sagging when we bought and is much better after having frame repaired by frame shop and new axle. Also have some of those spider cracks around the top hinge.

[John in Michigan]

You can use a dremel with stone tapered / pointed grinding bit to grind small channels along each crack, then fill and sand those channels, then gelcoat or paint. I can't tell from the photo whether its gel coat or paint.