: As far as your error goes, you can goad some one else into telling you more
: about that.

I've never laid fiberglass .. let alone burned resin off... hence know nothing of the process. But to me I would think that weighing the glass and then what was being glassed before adding epoxy, then to weigh the final result before sanding would be an accurate way of finding epoxy/glass ratio from the lay up. Was this your point George?