Sanding Epoxy Inlay to a Gloss

When sanding an epoxy inlay fill with a fine grit, a woodworker worries about finish adhering to the adjacent wood. December 31, 2013

Question (WOODWEB Member) :
We have been making large slab tables and filling large voids with a wood inlay and then covering with epoxy. In an effort to sand the epoxy to a glass-like finish we also have to sand the surrounding wood to a very high grit (1500). Is there a worry that the final finish, satin oil poly, will not stick to the finely sanded wood? Is there a better way to sand the epoxy to a glass finish?

Forum Responses
(Furniture Making Forum)
From Contributor O:
I've been doing the same, except for using black fresco powder mixed into the epoxy, which makes the epoxy look like a dark part of the wood, especially on woods like walnut. I just sand to the same grit as the rest of the piece, usually 220. The finish will then make the epoxy as glossy as you wish.

From the original questioner:
Thanks for the response. However, I am trying to see through the epoxy to see the inlay underneath, so a black epoxy will not work.

From Contributor O:
What I was trying to say is that the finish will make the epoxy transparent. I made a table many years ago where I actually made a dam around some parts of the slab and poured it full of epoxy, about 1/4" - 1/2" at a time. After sanding it, yes, it was cloudy and I couldn't see through it, but the first coat of finish made the whole epoxy buildup look like glass.

From the original questioner:
What kind of finish did you use?

From Contributor O:
It was something called "Humicure", which I can no longer get in California. Don't know if it's still available anywhere else. As I said, this was years ago. I would think that any clear film finish would accomplish the same thing.

From contributor C:
I would never sand wood to 150 grit. The highest you should go is 180. Your first coat is a sealer coat and itís the finish that you sand to achieve a level high gloss, not the wood. Sanding the wood so fine can definitely affect the adhesion of the finish.