Most aluminum alloys lend themselves to welding with either the GTAW(tig) or GMAW (mig) welding processes. There are some basic rules that apply no matter which process you should choose to use. If you follow these suggestions in a methodical way then you should be able to produce a sound weld. 1. Base metal and filler composition must match.
2. Surface oxides must be removed from both base and
filler metal.(Aluminum must be VERY clean to weld
successfully).
3. Pure Argon shielding gas (min.99.9%)should be used.
4.Because aluminum has high thermal conductivity,
it requires more power to weld than a similar
steel section.(preheat or increase amperage to
compensate.