A hole in a metal gas tank can be caused by road debris hitting the tank hard enough to puncture it, knocking out a piece of a vulnerable rusted spot on the tank. Since most holes in a gas tank occur on the bottom of the tank, it should be simple to locate. Using just a few supplies purchased at the auto parts store, a do-it-yourselfer can repair the metal gas tank and save himself the expense of a professional patching job.
Siphon any gas remaining from the tank into a suitable container, as you need a dry surface to perform the repair.
Ream out the 1/2 inch hole using the pick. Be sure to expand the hole enough to remove any surrounding rust. If the rust is all around the hole, use the sharp end of the pick to puncture the rust to remove it.
Sand the area around the hole, removing any paint, coating and surface rust. If all the rust and coating are not removed, the patch may not hold for long.
Mix the epoxy according to the directions on the package. Wear rubber gloves while performing this task, as the epoxy will become very hot once the mixture is made.
Apply a liberal layer of epoxy to the outer portion of the hole using the paint brush.
Place the fiberglass mesh on the epoxy on the tank, making sure to cover the hole completely. The mesh will stick to the epoxy. Paint a liberal amount of epoxy over the mesh, ensuring complete coverage of the mesh. Let dry completely.
