Notes on TIG Welding Aluminium

General Notes

  • 4043 Rod
  • A good baseline is to set an amperage equal to the material thickness (in thousands) So .125″ thick material would be 125 amps (I like to weld hotter than this… 150 or so is comfortable for me)
  • A basic ceramic cup is fine. The opening should be larger than your weld… but not by a lot.
  • A standard air-cooled torch is fine.
  • Use a tungsten tip, ground to a point, the size of which should be similar to or a little bit smaller than the thickness of your material. (The specific alloy won’t matter much, but avoid green.)
  • The amount of stick out is a preference, but a good baseline is 1/4″
  • Clean filler, tungsten, and material (acetone, mineral spirits, alcohol work well)

Welder Settings

  • Set welder to AC
  • 1-2 sec pre- and post-flow should be adequate, and the torch should be kept over the weld as it cools.
  • 15 CFM pure argon
  • Frequency around 120 (if the adjustment doesn’t exist, it’s probably 60htz)
  • The clean vs Penetrate knob adjusts the amount of time the AC curve is negative vs positive. Negative voltage is better at cleaning the oxide layer off the material; positive voltage is better at penetrating the material. So, if it has a thick oxide layer, you’ll want more cleaning. If it’s clean, you’ll want more penetration.

Welding Process Notes

  • The oxide layer melts at a much higher temperature (around 3,000F) than pure aluminum (around 1200F), so go heavy on the foot petal to melt through the oxide and then ease off. You cannot grind/clean through this as it develops in nanoseconds as it contacts oxygen.
  • It takes 1-4 seconds to form a molten pool.
  • Always tack along the whole weld (otherwise, it’ll warp because aluminum sinks the heat)
  • The torque angle is 75-90 degrees, always in push orientation. The goal is to keep the shield gas (pure argon) covering the molten pool.
  • Keep the tip CLOSE to material (less than the thickness of tungsten), but never dip it into the pool.
  • Ride the molten metal pool’s edge with filler wire; it does not get introduced to the pool’s center.
  • The puddle should melt the filler, not the arch! You’ll ruin your tungsten if you stick filler in the arch.
  • Aluminum distributes heat (sinks it) very well, so for longer welds, ease off the pedal as you go because the material will heat up quickly.
  • Use lots of filler; a good baseline is 75%-100% of the size of your material.
  • End your weld by easing off the petal over 2-3 seconds, otherwise, it’ll crater or pop.