Can I use a clear one pack polyurethane turps based varnish over epoxy if I sand the gloss off the epoxy before applying the varnish?  Can I use a clear one pack water based varnish over epoxy if I sand the gloss off the epoxy before applying the varnish?  The directions for most one pack clear varnishes say to sand off any pre-existing coating on the wood before applying the varnish.