The Barn Find Build

[taff]

Agree, use epoxy if the part is made with epoxy or polyester resin.
Polyester resin if part is made with polyester resin

The seats have a white gel coat, this is normally a polyester resin, so I am thinking they are all polyester. And from memory of when I built my Fox.
If your familier, you can detect polyester while your grinding the back side, from the smell. (wear a mask while sanding and sniff after the dust settles)

Or hand sand a area of white gel coat with P180 grit, just a small area enough to get white powder on the sandpaper and smell = this is polyester.
Compare the back side sanding to that smell. If it's the same = polyester.

I was thinking...Instead of getting thin aluminum. Get a large soft drink bottle (Coke) something with non profiled sides.
And cut it down the length to fit the shape of the lip of the seat. Maybe that would work?

This is a good epoxy (from ACS) it has a quick drying hardener also.