[Jerry Parr WI]

Alcohol is in fact the solvent for shellac so coating a float with it is a waste of time. The purpose of the shellac is to prevent the cork from drying out not to prevent it from absorbing gas. A bare cork will not absorb gas but it will dry out. Consider that an uncoated cork is used to seal wine bottles. They are stored cork down so the cork does not dry. As long as the cork stays wet as in gas it will not sink. Coating the cork with something that doesn't dissolve in alcohol can help prevent drying but use it sparingly as it will make the cork heaver. The dried out corks that sink were dried long before alcohol was added to the gas.