Can I apply epoxy over water-based polyurethane, polycrylic, or acrylic clear coat?

Not directly. UltraClear Bar & Table Top Epoxy does not bond to water-based polyurethane, and the same applies to polycrylic, waterborne spar urethane and clear acrylic spray coats. Epoxy poured straight over these finishes can fish-eye or delaminate.

The fix is to seal the water-based finish with 3 coats of an oil-based polyurethane. Let the oil-based poly dry for at least 24 hours, then apply your epoxy seal coat and flood coat as normal. Check the instructions for your water-based product for the right way to sand and prep it before the oil-based coats go on.

Sanding the old finish off is not a reliable shortcut. Wood absorbs water-based poly when it is first finished, so even with the surface film removed there is still a risk the epoxy won't bond. Sealing with oil-based poly first is the safe route.

Oil-based polyurethane can add an amber tone. If that is a concern, test on a small area first; applying epoxy directly over a water-based finish risks delamination, so the oil-based coats remain the recommended route.

This only applies to water-based clear finishes. Latex and water-based paints, including a water-based primer, are fine: the epoxy can go over them once the paint has fully dried for at least 24 hours.

Instructions: https://cdn.shopify.com/s/files/1/0320/7168/0140/files/Epoxy-Instructions.pdf?v=1616443869 Tutorial videos: https://www.bestbartopepoxy.com/tutorial-videos/