I wouldn't use or trust epoxy for a gas tank repair....my choice would be lead...as a teenager, I worked in an auto body and radiator shop; we routinely repaired gas tanks by first cleaning them out with detergent and hot water, then filling them with C O2, and tinning a large area around the leak....once it's properly tinned, just fill the area with (lead/tin) solder....in the case of a gas tank and the cosmetic issue, I would create a minor "dent" around the hole and fill it with lead.....then, just wash the area with washing soda to neutralize the flux, prime, and paint!
