Learning how to weld aluminum can be tricky depending on the process used and the thickness of the aluminum. There are three basic methods to weld aluminum; they are gas, mig and tig welding.
How to gas weld aluminum.
This type of welding is not common but will be found in several maintenance industries such as refrigeration repairs. Generally it involves fusing very thin aluminum sheets using oxy acetylene equipment.
Aluminum by nature is difficult to determine the point as to where the metal will actually melt. Consequently trying to heat two parts of aluminum to join them can result in the metal simply ‘dropping out’ when the melting point is reached. Oxy acetylene welding aluminum therefore is a process that really can only be achieved through practice until instinctive knowledge lets the operator know when the material is close to melting point and when filler can be introduced.
How to weld alloys using a Mig Machine.
This is the easy way and most common way to weld aluminum. Mig welding uses a continuous wire feed of aluminum wire applied to the weld area. Mig welding aluminium allows welding of 1mm thick metal and upwards. Depending on the power of the Mig machine. Thinner aluminum may need to be spot welded to avoid blowing through, again this depends on the thickness of the wire electrode being used, the smaller gauge wire used the thinner the metal you can work on.
Sheet metals are mostly welded using mig welders; common use is in aluminum boat construction, gates, fences and light structural and architectural work.
Welding aluminum in heavy gauges is similar to that of welding steel. You will need to change the welding cable liner to one made of Teflon that will allow smooth running of the filler wire. Aluminum wire is far weaker than steel and requires less friction through the cable and gun. Also you will need to use pure argon gas as opposed to cO2 used in steel welding migs.
Welding alloy using a Tig welder.
Tig welding aluminum is also difficult and requires plenty of practice. Similar in a way to gas welding it consists of heating the metal to melting point using a tig welding torch and introducing a filler rod at the right moment to create the welding bead. learning how to weld aluminum using a Tig machine is the most satisfying as the finished job is a work of art. It requires a fair amount of skill and allows a finished weld to be as small as 1/16 inch wide.