Liners FAQs
Straight answers on choosing, fitting and looking after the wire liner in a MIG torch cable.
What does a MIG torch liner do?
The liner is the guide tube that runs through the torch cable and carries the welding wire from the wire feeder to the contact tip. It supports the wire along the way so it does not buckle or snag, and a good one lets the wire run with little friction.
Because every metre of wire passes through it, the liner wears over time. A worn, dirty or wrong-sized liner is one of the most common causes of poor wire feeding and an unsteady arc, so it is worth checking before blaming the machine.
How do I match the liner to my wire diameter?
Each liner is made for a range of wire sizes. A bore that is too large lets thin wire wander and buckle, which causes poor feeding and wears the liner out faster. One that is too tight adds friction and drag.
Check the size range printed on the liner or its packaging against the wire on your spool, and change the liner when you move to a different diameter. Matching the liner to both the wire size and the wire material gives the smoothest feed.
How do I cut a new liner to the right length?
Always check the torch manual first, as methods differ. A common method is to remove the front-end parts, release the retaining nut at the back, pull out the old liner, feed in the new one with the cable laid straight, then trim it at the neck end so it sits just below flush with the tip holder thread.
Cutting the new liner to the same length as the old one is a useful shortcut if the old one was right. Do not cut it so short that a gap forms behind the tip.
How do I know the liner needs replacing?
Typical signs are wire that starts, stops or stutters even when the roller tension is correct, more bird-nesting behind the drive rolls, and metal shavings, rust flakes or dust coming out of the liner. A kinked, clogged or damaged liner also needs replacing.
Another cue is changing to a different wire size or type without changing the liner. If the wire drags heavily when pulled through by hand, the liner may be blocked or kinked. Clearing it with dry air can help briefly, but replace it if the drag remains.