If you can tig weld aluminum, does that mean you can also tig weld steel?
If the same technique works for both, then why do they seem so different?
What is so hard about tig welding aluminum?
If you can tig weld steel, you can tig weld aluminum. ...But
it takes practice, and it takes an ac/dc tig machine with high frequency type current to start the arc and keep it steady.
If you watch the video closely, I think you will agree, that I am use essentially the same exact technique to tig weld steel as I do to tig weld aluminum.
• create puddle that is about 4-6 times as wide as the thickness of the metal ( up to 1/8" sheet metal...after that multipass applies)
• add rod
• move puddle ahead about 1/16" to 1/8" depending on how tight you want ripples
• add rod
• lather rinse repeat.
so if the same technique works to tig weld aluminum, why does it seem so different?
Aluminum conducts heat much better than steel and so it takes a lot more amperage to weld...at least until it gets hot, and then it doesnt take much amperage at all.
for example, when welding a small piece of aluminum about .125" thick and maybe 4 inches square, at first you might need as much as 125 amps but after a few seconds, the piece will be saturated with heat the aluminum puddle can be maintained with just a few amps.
But the main thing that makes aluminum harder and different to weld is that everything that can go wrong with steel, seems to go wrong worse with aluminum.
• when you tig weld steel, you can sputter the electrode a bit in the puddle and get away with it.
• when you tig weld aluminum, the metal seems to want to jump on the electrode.
• when you tig weld steel, you can use as little as 10 cfh or as much as 30 cfh on your shielding gas flow rate, and sometimes not notice a difference.
• when you tig weld aluminum, too little flow or too much flow of shielding gas makes a big difference. and just a little too much flow, can make the arc really loud and make the arc erratic.
both steel and aluminum need to be clean in order for the weld to look good.
for hot rolled steel, a sanding disc , grinding wheel, carbide burr is needed to remove the mill scale.
for cold rolled, sometimes just an acetone wipe.
To clean Aluminum prior to welding really depends on the application.
If the aluminum is brand new sheet and is not oily, I just weld it.
If it is oxidized, has a coating, or if its an oily casting, then more cleaning is required.
Sanding discs, scotchbrite, carbide burr, etc are all methods that apply.
and Use only stainless steel wire brushes for aluminum.
more on tig welding and how to tig weld aluminum