Pretty much everything Bill posted. I started as a kid using clear dope, I use finishing resin when I have some in my shop, I have been using thin epoxy using 90% alcohol to thin it most the time. I have even used fuel proof paint for the inside of wood cowls. I haven't tried the varnish though or poly U for fuel proofing. I always have 30 minute epoxy and alcohol in my shop so that is my number one product.