David Weaver
..I was thinking also that layers of the super toxic 50% solids crosslinked finish may also be good. Even the typical water based finishes with cross linker dry really hard (without it, they dry like a semi-hard plastic layer that would be cut by a chisel too easily).

The table top finish type that I ordered has a 50-70 minute working time and I get the sense that table top finish may not have been the first use. It says something about being suitable also as a glue, casting or for working with fiberglass, and for making filled resins.

Lots of options - as tiny as linde A is, the challenge is getting a usable surface that won't collect contaminants or that doesn't already have abrasive power greater than the tiny abrasive. When the epoxy arrives, I will try a 50% abrasive concentration of it by weight (which is a little bit below most resin hobbyist waterstones - they are usually more like 60 on the low side and 80 on the high side).