Wanna learn how to TIG weld aluminum?
First you need a decent TIG welding machine. Not a great one, just a decent one. Already got one? You might have an old Synrowave 300 or a DialArc, an old Hobart CyberTIG or you might have a brand new Miller Dynasty 350.
Know what? It doesn't really matter. The same principles apply. If you have an old as dirt TIG welding machine, you can still make good aluminum TIG welds. Weld beads that look like a stack of dimes.
First lets look at machine settings:
Set the polarity to A/c (alternating currrent)
Make sure to set the high frequency to continuous
Set the amperage to about one and one half amps per one thousandths of inch of thickness. (up to about 250 amps then things change quite a bit)
Set both the contactor and amperage switches to the remote positon.
Set the argon or argon/helium torch shielding gas to around 15 cfh. (if you are using a #7 cup) less if the cup is smaller.
Notice I said argon or argon/helium? Argon is not the only game in town. In fact, if you TIG weld any aluminum over about.063" thick, adding helium to the mix makes a huge difference.
Now lets talk tungsten electrodes
2% thoriated have received a lot of bad press for the radioactivity issue but they do work.
2% lanthanated electrodes are a really good all purpose electrode...good for TIG welding aluminum as well as steel.
Use the smallest electrode that will get the job done without quivering at max amperage.
Remote amperage control...you need a foot pedal. Period.
Once all the settings are ok, and assuming you are welding on 1/8" thick aluminum, grab a piece of 4043 filler rod in 3/32 diameter (rarely will you use a rod as thick or thicker than the metal you are welding)
extend the electrode tip about 1/4" past the tip of the TIG torch cup and pre purge the gas by tapping the foot pedal.
hold the torch like a big first grade pencil. touch the tip of the tungsten to the metal and then pull it back about 1/8 inch. flip your helmet down and press the pedal to initiate the arc.
don't melt the aluminum right away though, watch the black stuff cook away from the arcs cleaning action before you melt the metal. Then press the pedal far enough to create a puddle that is about 3-4 times the thickness of the metal you are welding.
Now comes the part on how to achieve the "stack of dimes" look. You get that by adding the same amount of rod and by moving the torch the same distance each time you add rod. Add rod, Step ahead 1/8 inch,Add rod, Step ahead 1/8 inch,Add rod, Step ahead 1/8 inch, lather rinse repeat. If you do this consistently, you will get evenly spaced ripples that look like a stack of dimes.
Of course it looks different from underneath the welding helmet and it is harder than it sounds, but this is really how you do it. All that is left is the doing. It takes practice and lots of quality seat time.
