My plan for the screws on the outside backing out under the molding is to use SS machine screws and poly lock nuts, run the screw all the way through the frame and the inside wall, run an aluminum strip down the wall inside and possibly outside, the molding outside will cover the head of the screw and the trim inside will cover the nut. I have some adhesive that is made just for bonding fiberglass to metal from Evercoat, it's $86 a tube and works great I have used it before on the race car. But I will know more on that repair when I get to it.
__________________
|