The contact tip goes first
Its bore goes oval under arc heat and the wire starts to wander before the tip looks damaged. Symptoms: erratic arc, occasional sticking, more spatter than usual at settings that used to work. Change it before adjusting anything.
Then the liner
The liner is a coiled steel tube guiding the wire from the rollers to the tip. It fills with the swarf that wire deposits, and it kinks if the torch is dropped or trodden on. Blow it out with compressed air periodically and replace it annually if you weld regularly.
The nozzle and diffuser
Spatter builds inside the nozzle and eventually blocks the gas holes in the diffuser, which produces porosity that looks like a gas fault. Anti-spatter spray helps; a periodic clean-out with pliers and a pick is the real answer. Nozzles crack eventually and are consumable.
The neck, last and least suspected
A bent swan neck kinks the liner inside it permanently, and no adjustment at the machine fixes the resulting drag. If a torch has been dropped or stood on, suspect it — a replacement neck costs a fraction of a torch.
The questions welders ask
How often should I change the contact tip?
When the arc changes, rather than on a schedule. In practice a tip lasts a few hours of arc time in clean conditions and far less with dirty wire. Keep a box on the shelf — the reason people weld with worn tips is that they only have one.
Can I clean a liner rather than replacing it?
Yes, and it is worth doing. Remove it, blow it through with compressed air from the machine end, and wipe the wire path. What you cannot fix is a kink — once the coil is deformed the wire drags there forever.
Last reviewed 2026-08-14