Liners FAQs
Straight answers on choosing, fitting and looking after the wire liner in a MIG torch cable.
Which liner do I need: steel or plastic?
Steel (coiled) liners are strong and resist buckling, and are normally used for steel wire. Aluminium and other soft wires feed better through plastic liners, such as PTFE, which have a smooth bore with less drag. Some makers also use other plastics for short, straight runs at lower duty.
Steel liners are generally avoided for aluminium, because the wire can pick up traces of steel and the rough bore causes drag. Check the wire type in the torch manual and choose the liner designed for it.
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.
What do the liner colours mean?
Many makers colour-code liners by wire size, often with coloured shrink wrap or end caps, so you can tell sizes apart at a glance. Some makers use the same colour on the feed rolls for the same wire diameter.
However, the colours and the ranges they cover differ between makers, and even between product lines, so never rely on colour alone. Read the wire size range printed on the liner or its packaging and check it against your torch manual or the maker's selection table.
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.