Aluminum TIG Quick Start Guide

Aluminum is a great building material and fun to weld. This guide will get you TIG welding as quick as possible, so you can spend your time practicing rather than being confused with information overload. Near the end is a troubleshooting list.

A welder tig welding aluminum with his POV of the weld puddle through a welding lens shown on right

Basic Aluminum Filler Rods

4043 and 5356 will cover you for almost everything. However, if you’re welding something critical it's important to identify the exact type of base metal and make sure you use the right filler rod.

4043 vs 5356 aluminum weld puddle

5356 is stronger than 4043 and slightly less fluid when welding. 4043 is more corrosion resistant, and is also better for cast aluminum.  In general, if given the choice, I have more luck getting a nice looking weld with 5356.

4043 and 5356 filler both work on 6061 aluminum. If you’re welding sheet aluminum, you may encounter 5052 which welds better with 5356.

Tungsten Selection & Prep

You don’t need to ball your tungsten if you’re using an inverter machine. You only need to ball your tungsten if you’re using a rectifier-transformer welding machine.

Diagram of tungsten prep for tig welding aluminum.

Type of Tungsten

This depends on who you ask, which usually depends on who he or she learned from. I prefer 2% lanthanated (blue) tungsten for aluminum welding, ground to a blunt tip (roughly 45*). This allows me to use the same type of tungsten for everything—mild steel, titanium, stainless, and aluminum. Simple. Easy. And works. 

Size of Tungsten

If you only have ONE size of tungsten, I would go with 1/8”. This will give you versatility, and if you’re learning, the larger size will help your tips hold up better. You can easily weld low amps with a larger tungsten, but you’ll have problems welding high amps with a small tungsten. 

Aluminum Prep

That shiny stuff you see when you think of aluminum is aluminum oxide—aluminum rust—on its surface. It doesn’t melt or flow into the puddle and needs to be removed. This is why you TIG weld aluminum with AC (more on that in the AC balance section).

  1. Wipe up general work area  
  2. Acetone wipe aluminum with a clean cloth or paper towel 
  3. Use a clean stainless steel brush (dedicated only to aluminum) to scratch surface oxide off 
  4. Acetone wipe aluminum again 
  5. Acetone wipe filler rod 

Torch & Gas

A #8 cup w/20 CFH (regular) or 25 CFH (gas lens) 100% argon is a good place to start.   

Machine Setup

  • AC Balance - You need the AC (alternating current) to remove the oxide layer from the surface of aluminum. Your electrode quickly changes between positive and negative. When it's positive, the oxides are pulled off the aluminum and the heat is going to your tip. When your electrode is negative the heat is going into the base metal to form your weld puddle. Set the positive from 25-30 for most applications, this is the percentage of time your electrode is positive. (Some machines read out the negative side, so you’ll want to set it somewhere between 70-75 on those)   
  • Frequency - Set it between 100-120 and forget it. If you don’t have a choice, then you’re likely using a transformer rectifier machine.  
  • AmpsAll the “rules” out there do more harm than good. You just need to see how many amps it takes to form a puddle. Start low and work your way up. As an example, I’m running 100-120 amps on the outside corner joint in the video at the bottom.  


  • Whiskers forming near the electrode tip and gunk in the puddle – Moisture contamination in the shielding gas 
  • Excessive spitting – Electrode contaminated
  • Point deterioration – Too high of current for that size of tungsten electrode, too sharp of point, too much electrode positive on the balance, or general contamination 
  • Arc wandering – Off center taper on the electrode tip
  • Porosity in welds – Oil or grease on base metal, not enough coverage gas, or coverage gas being blown away by drafts or wind in environment 
  • Black specks – Dirty filler rod or base metal, or contamination from a dirty work area
  • Lack of fusion – Not enough amps, too fast of travel speed, or arc angle too crooked
  • Weld cracking – Wrong filler metal, not using filler metal, too rapid of cooling from lack of preheat, or too much distortion and stress from welds 
  • Spatter – Dirty filler rod or too high amps 
  • Popping and hissing sounds – Wet filler or argon flow/coverage issues 
  • Filler rod curls up and bubbles and generally goes crazy – Usually means aluminum oxide flakes from brushing the base metal are contaminating the rod. Make sure to wipe everything off after brushing
  • Aluminum melts before puddle forms – Oxide layer on surface (the aluminum under the surface melts at a lower temperature than the oxide) needs better cleaning, or more positive on the AC balance. It's possible amps are too low, so the heat is spreading everywhere before getting hot enough to form a puddle under the arc

Most Common Types of Aluminum

There are two categories of aluminum. Wrought and Cast. Wrought aluminum alloys usually have a smooth uniform finish. Cast is usually textured.  

6061 (or something closely related) is the most common wrought aluminum you’ll encounter. This can be thought of as strong, lightweight, general-purpose project material.  

356.0 and 319.0 are the two most common types of cast you’ll likely encounter.   


Hit us up for free online welding instruction if you have questions or want feedback on your welds.  

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