Re: epoxy glassing wood. question?
Posted: Fri Aug 05, 2016 6:17 pmslowcowboy wrote:new to epoxy and glassing wood how soon can you sand after the epoxy kicks? what type of grit sand paper? slow
Wait until it is fully cured, which varies by speed of the hardener (fast/medium/slow) and the temperature. I've turned boats upside down in the winter with an electric heater underneath them to get the epoxy to cure in 50 degree temps. Partially-cured epoxy dust is not so good for you, so wear a good mask, gloves, and a long-sleeved shirt when you are sanding. I have had a couple of very mild rashes sanding in short sleeves, but with precautions you shouldn't have any issues. The worst part about using epoxy is the sanding.
If you are adding another layer of glass, I wait until the epoxy is tacky (not fully cured) then lay on the next layer and bed it in epoxy. Not letting it cure between coats makes the job go faster and (arguably) provides a better bond between the layers. If you are only using one layer of glass, just ignore this.
The grit depends on what you are doing. I've sanded boats where I wanted to remove globs fast, and used 60 grit, and other times used 150 if it was pretty smooth already and I was prepping for painting. The amount of sanding you do is determined solely by how smooth you want it to be.