Can resin or epoxy be poured over a poly finish?

Question

I pulled the tile out of my dining table and replaced it with multiple wooden slats that I torched, sanded, then stained. The valleys in the grain are amazing and I left a smooth board in the center with mine and my children's hand prints. The problem is the material I used when done was shorter that the area it was going into. I had planned on filling it with resin but couldn't afford it so I put some polyurethane on it to prevent damage. It's been covered and unused for months. Is it safe to fill in with resin/epoxy or anything that will level it without damaging what's there? I want to pour in a self leveling resin or epoxy that would spill over the sides to completely fill in the center and create a level surface. It's completely covered in poly right now. The soft grain in the purple boards has been ground out after blow torching the wood leaving the hard grain black. You can feel every ridge and valley running your fingers over it. Would that help with bonding. I can't really remove the poly without damaging the color underneath. I could completely strip the black perimeter of poly if that would help. There's also minor gaps in-between enough of the pieces that whatever I pour would be able to get in and underneath the edges of the strips.

Answer 1

Is it safe to fill in with resin/epoxy or anything that will level it without damaging what's there?

We don't know quite what you're facing but epoxy doesn't damage cured poly so you're fine as far as that goes. But if there's poly anywhere where the epoxy is intended to be you won't get any decent bond.

All film finishes offer some level of protection from epoxy bonding. If you pre-finish stuff you can see this effect for yourself (and learn to rely on it) since excess epoxy lifts off the surface with very little effort — up to the point that it can sometimes be picked off just with your fingernails.

Edit based on photo added
I think you should do something to help ensure a good bond here. Ideally such a poured finish will go on to bare wood which has plenty of microscopic texture for the resin to bond with. Since that's no longer an option it would help a lot to provide some microtexture for the epoxy to grip.

A gentle scuffing of the surface with fine Scotch-Brite or similar, or lightly sanding with a cushioned sanding block and 320 abrasive is enough. You're just looking to produce a reasonably uniform matt surface finish to create what's called a 'mechanical bond'.

Brush/blow/wipe/vacuum the dust off — ideally in another room to the one you're intending to do your pour in, since fine airborne dust can remain in the air for an amazing amount of time (hours).