Re: will epoxy bond with gelcoat?
I didn't read the original post (my bad) so the sanding off of the gelcoat isn't needed.
For this, as some have posted, I'd recommend a PVC board, or if you don't want to use them because of price or looks, you can use a piece of vinyl trim board the right size from your local big box home improvement store.
I'd recommend 5200 for attachment, plus two long stainless screws. The process for attachment should be:
1) Locate and mark the position of the board on the transom, including the screw holes. If the board has no holes, drill them first.
2) Overdrill the screw holes marked in the transom with a bit about 1/4" larger than the one you'd drill pilot holes with for your screws. Drill to the depth you'll need plus a bit, but avoid drilling through the transom.
3) Fill the holes flush with the transom with epoxy thickened with cabosil and milled fibers or wood flour.. cabosil alone will work in a pinch.
4) Once cured, you sand as needed to clean up the holes, which are now plugged flush with solid resin. Then you drill centered pilot holes in those plugs using a correctly sized bit.
5) Sand the back of the vinyl or pvc board a bit, or use another means to rough them up (follow the mfgr. directions for the PVC)
6) Apply 5200 around the edges of the board (back a bit from the edge, because it'll squeeze out) and place it in position on the transom. Hold it there while you thread the screws into the holes, then tighten the screws down all the way. Be prepared to wipe/catch any squeezed out 5200.
7) Use a popsicle stick to form fillets around the edges of the PVC board, and then clean up excess 5200 as the manufacturer directs.
8) You can start mounting right away if you like, but a day or so to start curing of the 5200 avoids messes. Make sure you mount with screws short enough to not fully penetrate the plastic board and make a hole in the transom.
Erik
