Miller Millermatic 190 Owner's Manual page 42

9-16. Common GMAW (MIG) Shielding Gases
This is a general chart for common gases and where they are used. Many different combinations (mixtures) of
shielding gases have been developed over the years. The most commonly used shielding gases are listed in the
following table.
Gas
Spray Arc Steel
Argon
Flat & Horizontal
Argon + 1% O
2
Fillet
Flat & Horizontal
Argon + 2% O
2
Fillet
Flat & Horizontal
Argon + 5% O
2
Fillet
Flat & Horizontal
Argon + 8% CO
2
Fillet
Argon + 25% Flat & Horizontal
CO Fillet
2
Argon + 50%
CO
2
Flat & Horizontal
CO
2
Fillet
Helium
Argon + Helium
4
Tri-Mix
1 Globular Transfer
2 Heavy Thicknesses
3 Single Pass Welding Only
4 90% HE + 7-1/2% AR + 2-1/2% CO
5 Also for GMAW-P, All Positions
9-17. Troubleshooting Guide For Semiautomatic Welding Equipment
Problem
Wire feed motor operates, but
wire does not feed.
Wire curling up in front of the
wire feed rolls (bird nesting).
OM-264761 Page 38
Short Circuiting
Steel
5
5
5
5
All Positions
1
All Positions
All Positions
1
All Positions
2
Probable Cause
Too little pressure on wire feed rolls.
Incorrect wire feed rolls.
Wire spool brake pressure too high.
Restriction in the gun and/or assembly.
Too much pressure on wire feed rolls.
Incorrect cable liner or gun contact tip size.
Gun end not inserted into drive housing properly.
Dirty or damaged (kinked) liner.
Application
Spray Arc Short Circuiting
Stainless Steel Stainless Steel
5
Flat & Horizontal
Fillet
5
Flat & Horizontal
Fillet
All Positions4
All Positions
Increase pressure setting on wire feed rolls.
Check size stamped on wire feed rolls, replace to match
wire size and type if necessary.
Decrease brake pressure on wire spool.
Check and replace cable, gun, and contact tip if
damaged. Check size of contact tip and cable liner,
replace if necessary.
Decrease pressure setting on wire feed rolls.
Check size of contact tip and check cable liner length
and diameter, replace if necessary.
Loosen gun securing bolt in drive housing and push gun
end into housing just enough so it does not touch wire
feed rolls.
Replace liner.
Spray Arc Short Circuiting
Aluminum Aluminum
5
All Positions All Positions
2
All Positions
2
All Positions
Remedy