Someone asked me recently ” why are there so many different kinds of tig cups?”
I also get lots of questions about how to weld aluminum.
So I thought of a joint configuration using some aluminum square tubing that would help demonstrate how different kinds of tig cups are used to weld aluminum and other metals.
Here are the highlights:
An acetone wipe down before welding usually helps a lot.
smaller tig cups are usually used for getting into tight angles but sometimes a gas lens cup works just as good or better by letting you extend the electrode. That saves time too by letting you use the same cup for all kinds of situations. But sometimes I like a small cup when the job allows for it because a #4 cup only requires about 8-10 cfh of argon flow…(thats important when you are low on gas and its Saturday evening and the job needs to be done before Monday.)
When you weld aluminum, there is a cleaning action from the arc that cleans away the oxide film so when you are making tack welds or starting a bead, it helps to let that cleaning action work and cook away the smut before actually puddling the metal. In other words, if you are having trouble with contamination, take your time and sneak up on it letting the cleaning action dance around a bit before you melt anything.
you can avoid crater holes when you weld aluminum by adding an extra drop or two of filler rod while wiggling the arc around as the amperage tapers.
Moving the arc 1/8″ and adding filler while you pause will give you the “stack of dimes” look ( not that a stack of dimes look is important for quality but that look seems to be sought after)
A TIG finger lets you prop near an aluminum weld without cooking your knuckles.