TIG Cups and Argon Flow Rates for TIG Welding Stainless Steel

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Cup size and type selection

The cup size and type that works best on stainless depends on several factors. But for General Stainless fabrication a jazzy 10 ceramic or furick 12 ceramic are great choices.

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Proper Gas Shielding

• Shielding Gas Types (Argon, Mixtures)
• Gas Flow Rates and Gas Coverage 
• Cup size and type selection
• Avoiding Contamination

The most widely used shielding gas for TIG welding stainless as well as purging stainless steels is:

1. Pure Argon

• Why It’s Popular:
  while there are a few argon mixes used for very specific stainless welding procedures, Pure Argon remains the most widely used shielding gas for TIG welding stainless steels due to its excellent arc stability, low cost, and versatility. It provides an inert atmosphere that protects the weld pool and surrounding metal from oxidation. Since argon is heavier than air, it displaces oxygen well when used for purge gas.
• Applications:
  Used for both shielding and back purging, argon ensures clean, high-quality welds with minimal spatter.

Nitrogen is usually cheaper than argon and some contractors use it for purging stainless but Pure argon is the most commonly used and most versatile gas for purging. 

Argon Gas Flow Rates for different size TIG cups

The gas Flow rate needed for a given cup size is around 2 to 3 CFH multiplied by  cup size depending on how drafty the shop is and other factors like joint type. 

This chart uses a factor of 2.5 which is a great starting point for tig welding stainless but you may want to experiment with slightly higher flow rates due to differences from one flowmeter to the next. 

This video shows examples of different cup sizes being used on stainless as well as other metals.

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Avoiding Contamination

Stainless steel can lose its stainless properties if contaminated during the welding process as well as pre and post weld cleaning.

• Make sure the stainless is clean prior to welding.  That could be as simple as a wipe down with acetone, or it could involve using abrasive cleaning.
• Use only grinding wheels, wire brushes, and abrasives that are dedicated to stainless and that have not been used on carbon steel.
• Clean the stainless prior to weld to remove any shop grinding dust 
•  Use only stainless wire brushes that have not been used on other metals
• Files, carbon burrs, and other tools should be dedicated for stainless also
• Wipe filler metal with acetone, or other solvent