Ca would work, but it is messy, smelly, and will bubble and be rough. 30 Minute epoxy is the way to go. Lay your cloth on the bottom first, no need to tack it. Static electricity should hold it down fine. Mix a batch of epoxy, and smooth it onto the surface. No thinning required, and not recommended. If it seems too thick, grab your heat gun and heat it a little, then spread. You only need enough epoxy to fill the weave of the glass, so scrape off all that extra before it cures. Try to get as smooth a surface as you can. Once the bottom is cured, do the top the same way.