I've been told that you should use at least 90% rubbing alcohol for thinning epoxy. The more common, in our markets/grocery stores, is 70% and that is reported to make the epoxy rubbery...

Rubbing alcohol is sold by varying percentages and I was told to use the 90% type. I am not saying that you should use 9 parts alcohol to 1 part epoxy for fuel proofing purposes...

BTW -- what is a good ratio of epoxy to alcohol for fuel proofing?