1. The best feeding of wire for aluminum is done with a spool gun. If you can’t use a spool gun, use the shortest gun possible and keep the gun as straight as possible. Use Argon only for shielding gas. Only use a push gun technique when welding aluminum.
2. If you are having feeding problems, one thing you can try is a contact tip that is one size bigger than your wire.
3. The most common wire type is ER4043 for all-purpose work. ER5356 is a stiffer wire (easier to feed), and is used when more rigid, higher-strength weld properties are needed.
4. Clean the aluminum before welding, to remove the oxide layer. Use a stainless steel wire brush used only for cleaning aluminum.
5. Fill the crater at the end of the weld to avoid a crack. One way to do this is to dwell in the weld pool for a second at the end of the weld.