Troubleshooting
Why the weld is porous, why the electrode sticks, why the wire keeps birdnesting.
Fault-finding by symptom, with the causes ordered by how often they are the answer rather than by how interesting they are.
One rule covers most of this section: the machine is usually innocent. A sticking electrode is normally current or the return connection; erratic wire feed is normally a contact tip; a tripping breaker is normally the wrong breaker curve or a coiled extension drum. Working from the outside in — consumables, connections, cables, supply, then the machine — resolves the great majority without opening a case.
- The electrode keeps sticking Current too low, damp coating, a poor return connection or the wrong striking technique — how to tell which one you have.
- Wire feeding problems Why the wire jams, slips or birdnests: the liner, drive roll pressure, the contact tip, the spool brake and how the cable is routed.
- The welder trips the breaker Inrush current, breaker curve, supply cable cross-section and duty cycle: the reasons a machine trips a domestic supply.
Frequently asked questions
The electrode sticks. What do I check first?
Add 10 A. Most cases end there. If it still sticks, look at the return clamp and what it is attached to, then at the cable size, then at whether the electrodes are damp.
The MIG arc stutters but the wire feeds normally.
Then it is electrical contact, not feeding: the contact tip has worn oval and the wire is arcing inside it. A tip costs almost nothing — change it before investigating anything else.
The breaker trips as soon as I switch the machine on.
Inrush current against a type B breaker. An inverter charges its capacitors at switch-on and a type B curve reads that as a fault. The fix is a type C breaker, fitted by an electrician — not a larger fuse of the wrong curve.