How to Weld Aluminum. Welding aluminum is a challenging task. While the welding itself may seem simple if you're just following the short instructions of the welder manual, in reality the aluminum can warp, crack, bend or simply not stick. To weld aluminum successfully and safely follow these steps.
Gather your equipment. In addition to the welder, which should be a Tungsten Inert Gas welder if possible, you need welding gloves and a welding helmet. You also need some technical equipment and supplies such as argon gas, an aluminum-specific welding rod and an aluminum dedicated stainless steel brush. You also want to wear a thick long sleeve shirt to prevent yourself from getting burned.
Clean the aluminum. You must clean the aluminum pieces you are using before attempting to weld them. You can clean the aluminum by spraying the surface with electrical cleaner. Rinse the cleaner off of the metal with some clean water and then scrub the surface of the metal with a stainless steel brush to remove any remaining dirt or residue.
Use a heat sink. Because of aluminum's tendency to conduct heat very well you need to use a heat sink to clamp the aluminum onto in order to prevent the metal from warping or the workspace from becoming to hot to work around. A copper or aluminum heat sink is the best way to go.
Preheat the aluminum. Starting with preheated aluminum will make the welding job a lot more sound. Preheat the aluminum by sticking it in an oven with a thermometer or by using a propane torch to heat the surface. You should try to get the metal to around 300 or 400 degrees F. This will make the actual welding process much easier.
Make sure the pieces are flush when you weld. Aluminum has a tendency to preserve spaces between the metal pieces as you weld. You can use filler in between spaces or you can pay special attention to areas that don't seem to be fitting together perfectly. Either way, make sure the aluminum slides together as tightly as possible as you weld the pieces.