When repairing aluminum boats, most methods call for either welding or fiber glassing the area in need of repair. While both methods are acceptable in repairing aluminum boats, the purpose of the repair often dictates the method used. For a durable, long-lasting and strong repair to a damaged hull, welding is commonly thought of as the best and most proper method of making the repair. If the needed repair involves simply eliminating a slow leak in a riveted seam, fiberglass is often considered the best method of repairing aluminum boats. If, however, the reason for repairing an aluminum boat is to complete a restoration, then welding, grinding and polishing is going to give the most traditional and original-appearing finish once the repair is completed.
Regardless of the method used in repairing aluminum boats, the most important factor is to thoroughly clean the repair area prior to attempting any repair work. The use of a mild acid to remove any oxidation from the aluminum and sanding the damaged area to ensure strong material is being worked on is the No. 1 tip in repairing aluminum boats. Attempting to place fiberglass on uncleaned aluminum will result in the fiberglass peeling off of the aluminum in a very short amount of time. Welding over dirty aluminum will result in a contaminated weld that will oxidize and actually eat itself, leaving several small holes in the repair area.
The tip that may actually save the repairman's life is to use a breathing apparatus when welding on aluminum. Aluminum produces a toxic gas fume when it is welded, making repairing aluminum boats a very dangerous practice if the proper precautions are not taken. For the repair of very thin aluminum, a good tip is to use a torch and braze the repair instead of welding it. The brazing process will use less heat and not damage the surrounding metal. In some instances, welding will result in melting a bigger hole in the boat than was originally requiring repair.
High in the priority of the tips list for repairing aluminum boats is to take time and not rush the repair. If rushed, a slip-shod repair can actually ruin an aluminum boat. For example, if repairing a crack in a hull, it is recommended that a small hole be drilled at each end of the crack, and then the crack can be welded closed. Failure to do this added step of drilling the ends of the crack when repairing aluminum boats can often lead to the spreading of the crack right through the weld area.