Epoxy Over Water Based Poly
We do not recommend putting the epoxy over water-based polyurethane. The epoxy could cause the water-based polyurethane to wrinkle or soften. Also, Epoxy does not stick very well to water-based polyurethanes and you could end up with fisheyes (epoxy pushing away from the surface). We recommend applying 2-3 coats of oil-based polyurethane over the water-based coating so that the epoxy will stick to it. It is also best to test it out first on a small scale test to be safe.