False False
False
False
False

Plasma Arc Welding Gases

Low Current Plasma Arc Welding Shielding Gases

Argon is generally the preferred orifice gas.

MetalGaugeKeyholeMelt-in
Carbon SteelUnder 1/16"Keyhole tech, not recommendedArgon
Helium
HeliStar A-75
Carbon SteelOver 1/16"Argon
HeliStar A-25
Argon
HeliStar A-25
Stainless Steel Under 1/16"Keyhole tech, not recommendedArgon
Helium
HydroStar H-2
Stainless Steel Over 1/16"Argon
HeliStar A-25
HydroStar H-5
Argon
Helium
HydroStar H-5
AluminumUnder 1/16"Keyhole tech, not recommendedArgon
Helium
AluminumOver 1/16"HeliumHelium
CopperUnder 1/16"Keyhole tech, not recommendedHelium
HeliStar A-75
CopperOver 1/16"Helium or HeliStar A-25Helium

High Current Plasma Arc Welding

Gas selections shown are for both the orifice and shielding gas.

MetalGaugeKeyholeMelt-in
Carbon Steel Under 1/8"ArgonArgon
Carbon Steel Over 1/8"ArgonHeliStar A-25
Stainless Steel Under 1/8"Argon or HydroStar H-5Argon
Stainless Steel Over 1/8"Argon or HydroStar H-5HeliStar A-25
AluminumUnder 1/4"ArgonArgon
HeliStar A-75
AluminumOver 1/4"HeliumHelium
HeliStar A-25
CopperUnder 3/32"ArgonHelium or HeliStar A-25
CopperOver 3/32"Keyhole tech, not recommended *Helium

* The underbead will not form correctly. However, on Cu-Zn alloys a keyhole technique can be used. A65