Casting a resin tabletop with an ‘iceberg’

Hi Rick,

This one is tough. It’s not my area of expertise, but I will share with you what I know.

Polyester resin will create the ‘cracked’ appearance if it heats up too quickly. The easy way to make it do that is to add more hardener than in recommended. The problem with using polyester resin for this project is that it shrinks enough after cooling that it will likely pull away from the wood.

Polyurethane resin is likely what someone used, but I don’t know how they created the ‘cracked’ look.

I wish I could be of more help. I will see if I can get a resin and woodworker to chime in.

I asked one of my woodworking contacts to share his thoughts. Here’s what he had to say:

“I think you hit on it with the catalyst .. using too much can lead to cracking
and pouring too much at once can do the same thing.

As for the shrinkage.. the nice thing about polyester resins is that they
will bond to a previous layer. So if you pour thick, let it crack and then
pour again with a thin layer, you can get a smooth outer shell with no
cracks over the cracked interior. The thinner you pour, the less shrink
you get, so it should fill in quite nicely, I think. And the top layer should
bond well to the interior without showing any lines. Then you can polish
out the surface with compounds or micro-mesh.
Should look pretty cool!”