7 Tips (Actually 8) for TIG Welding Aluminum

7 TIPS FOR TIG WELDING ALUMINUM

1. A simple turn of the AC balance knob can make a huge difference. When you set the AC balance to not enough cleaning action, you get black dots in the weld puddle.  A simple turn of the knob can usually clean up the puddle.
2. A small inboard tack can prevent the end tack from breaking when welding from an end on aluminum. Aluminum is hot short and weak when hot so a tack weld on the end can turn loose if you start on the tack. By adding a small tack a half inch inboard, you can avoid lots of problems.
3. Making big steps on thick aluminum is usually not a problem but for thinner aluminum, big steps can create a hole..especially if there is any gap at all…frequent dabs of filler rod at frequent spacing helps prevent problems on thin aluminum.
4. High AC frequency might be annoying to hear without ear plugs but can really focus the arc….if your machine has enough amperage to handle higher frequency settings. Sometimes its worth it to put in some ear plugs. The primeweld 325x is capable of tig welding .125" aluminum on 115 volt power for short runs...even with the water cooler running.
5. The rule of 33 can be a big help on thin steels but also can help on thin aluminum. The rule of 33 is a pulse setting using 33 pulses per second with 33% background and 33% pulse width. 33 pulses flutters the arc and agitates the puddle but is not difficult to watch. I personally don't use pulse rates above 2pps or below 33 due to it hurting my eyes and giving me a headache. 
6. Thick open corner joints that need a wide bead can benefit from a low AC frequency setting like 50hz…especially if you are pushing the upper amperage limits on your tig welder.
7. 120hz is a great all around AC frequency setting if you just want to set it and forget it.  In fact, some machines like the miller diversion have an AC frequency fixed at 120hz because they feel it is a good all around setting.