Will epoxy stick to polished petrified wood or other very smooth surfaces?

Yes, with a light scuff sanding first. UltraClear Bar & Table Top Epoxy is the best choice for top-coating petrified wood slabs. It provides a 1/8" thick layer of glass-like resin and is our strongest, most scratch-resistant epoxy.

Epoxy needs a little texture to grip. On a surface polished to a high shine it has nothing to bond to, so lightly scuff sand it with 220-320 grit. This does not require aggressive sanding or removing material, just enough to dull the surface evenly. Then thoroughly clean off all dust and residue and let the piece dry completely. Once it is sanded, clean, and dry, apply the seal coat and flood coat as normal.

The same principle applies to other glossy, non-porous surfaces such as glazed ceramic. When resin separates from the edges of a ceramic dish long after curing, the usual cause is an extremely smooth surface or residue such as oils, soaps, or waxes that prevents a proper bond. For UltraClear Art & Craft Epoxy on ceramic dishes, lightly sand the ceramic (around 320-400 grit is a good starting point; test first), clean it thoroughly with denatured alcohol, let it dry fully, and avoid touching the surface after cleaning. Applying a thin seal coat before the main coat can also help.

Bar & Table Top Epoxy: https://www.bestbartopepoxy.com/products/epoxy Art & Craft Epoxy instructions: https://ultraclear.helpscoutdocs.com/article/864-art-craft-epoxy-instructions