Forney 140 MIG Operator's Manual page 19

PROBLEM
Wire burns back to
contact tip.
Workpiece clamp and/or
cable gets hot.
Gun nozzle arcs to work
surface.
Wire pushes torch back
from the workpiece.
Poor quality welds.
Weld deposit "stringy" and
incomplete.
Weld deposit too thick.
POSSIBLE CAUSE
Contact tip clogged or damaged.
Wire feed speed too slow.
Wrong size contact tip.
Bad connection from cable to
clamp.
Slag buildup inside nozzle or
nozzle is shorted.
Wire feed speed too fast.
Nozzle clogged.
Torch held too far from the
workpiece.
Insufficient gas at weld area.
Rusty, painted, oil or greasy
workpiece.
Rusty or dirty wire.
Poor gound contact.
Incorrect gas/wire combination
Torch moved over workpiece too
quickly.
Gas mixture incorrect.
Torch moved over workpiece too
slowly.
Welding voltage too low.
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POSSIBLE SOLUTION
Replace the contact tip.
Increase wire speed.
Use correct size contact tip.
Tighten clamp connection or
replace cable.
Clean or replace nozzle.
Decrease wire feed speed.
Clean or replace nozzle
Hold the torch at the right distance.
Check that the gas is not being
blown away by drafts and, if so,
move to more sheltered weld area.
If not check gas cylinder contents
gauge, regulator setting and
operation of gas valve.
Ensure workpiece is clean and dry.
Ensure wire is clean and dry.
Check gound clamp/workpiece
connection.
Check the manual for the correct
combination.
Move the torch slower.
See shielding gas table.
Move the torch faster.
Increase welding voltage.
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