Sealing/curing laminating polyester?

I'm building new countertops at the moment. If I apply non waxed polyester resin....will it cure when I pour the epoxy on top even if it is days between...or shall I apply waxed polyester and sand it instead ..before applying the epoxy?


....I'm used to work with waxed polyester...somebody in the boatyard said it would cure if misting water on the non waxed one....Would it?

 

You can’t pour epoxy over polyester in that way, you can only apply it to a fully cured and prepped surface.

Water brings the cure process to a complete stop, so misting water on the surface is exactly what you don’t want to do.

 

You could try coating it with PVA mould release, then wash that off thoroughly, later, before applying the next coating. Unless ondarvr contradicts that, he'd know better than me. I guess you'd know if it was tack free after that process.

 

Yeah I know about PVA but it is hard to find in central America.

Ok...So the polyester won't cure if sealed from the air with epoxy? Or is it a bad adhesion for the epoxy? The epoxy is just to be poured to make a cool effect.

 

I have also heard that it is no good putting epoxy over tacky polyester, and ondarvr is well versed in these matters. There may be something else you can paint over it with, that will wash off easily.

 

The chemistry of the two are not compatible unless fully cured, there can be zero bond and/or an inhibited or no cure situation when one is used over the other.

Always allow for a complete cure, then clean and sand the surface, this goes both ways.

 

One trick I use for a finish cure as I don't like adding wax or PVA is cover the last coat of PE with wax paper. It will inhibit the air contact and if your dealing with a flat surface placing something with a smooth surface over it like MDF or Melamine. Think of it like a reverse mold.

You'll retain some wax on the surface when you peel it off so a good sanding and cleaning with acetone will be required as any final preparation would.

 

Yeah I hav heard about the wax paper and celuphane...good idea.

For some shelves I'm making...I have nidacore honeycomb. Formica on both sides....can I glue the Formica to the honeycomb with polyester which then gets encapsulated and cure?

 

Polyester resin isn’t a good glue, and I have no idea how well it would bond to Formica.

As for the cure, it would cure correctly, no wax, PVA or anything else would be needed

 

Formica is largely melamine, I think.

 

The side of the Formica that you bond to has a surface treatment for better bonding, but I don’t know how well it would work with polyester.

 

He might experiment with a small sample.