That was what I was after. I made patches from some school grade foam board but they need to be backed up with something then sealed.
So just use tape on the back side and resin on the fabric side. Makes sense. I looked up gaffers tape but it says it is waterproof on the backing so not good for resin? Or am I looking at the wrong stuff? Either way I think my industrial duct tape on the back side will hold the resin from soaking through. Then I can seal with resin. And for a large broken repair area then maybe a local layer of glass mat on the fabric side for good measure. Then layers of resin until it doesn't soak in any more? I am beginning to see this working.
In my firebird I filled the worst of the problem areas on the fabric side with skim coats of body filler believe it or not. I did it after the first coat of resin so it had a bit of a shell surface to bite into. Got gid of the repair seams then the next layers of the resin encapsulated the filler into the repair itself.
I see the ortho doc Thurs afternoon. If I'm as laid up as I'm led to believe, for as long as I'm led to believe, maybe I'll do one of the c10 headliners that are lying around in wait of repair.
One thing I'll caution that I don't know if I already did, or not.... when you do your fabric, make sure to have it overhang the board by about 1.5-2" on every side so you can wrap it around to the back after.