I have an S&G kayak I built 15 to 20 years ago that I am refurbishing. Directly under the ethafoam seat I had velcroed in I found a delamination of both the fiberglass and some plywood.

I have cut out and all of the bad stuff including the inside face ply, approximately 50 sq. in., where it had delaminated. At this point everything looks solid and dry.

My plan is to:
1. Epoxy coat all of the raw areas.
2. Fill in the missing face ply area with System Three Quikfair.
3. Cover the area with a piece of 7.5 oz. fiberglass.

Does anyone have any insight as to why my repair method might be bound for failure?