How to Properly Feed & Tension Your MIG Wire

Getting the tension correct on your MIG machine is one of those minor things that isn’t mentioned very often but can significantly impact your welding.

The drive rollers in a MIG welder work to pull the wire from the spool and feed it down the torch liner and out the torch tip. This is done by the drive motor in the unit, and the groove in the rollers provides tension to the side of the wire, allowing it to be pushed.

The tension knob is important because it determines how much pressure is applied to the wire while it’s in the groove of the drive rollers.

Why Is the Correct Tension Important?

Proper tension will give you a consistent wire feed and a stable arc.

If there’s not enough tension on your wire, it won’t feed properly. The wire will slip in the drive rollers, likely causing it to birdnest. Not enough tension will also make your arc stutter as the wire is what acts as the electrode, and if there’s not any wire being added and conducting, the arc will falter.

Too much, and it can flatten or deform your wire, causing feeding issues further down the torch and creating an unstable arc. Too much tension on the wire will also cause it to birdsnest at the rollers if something restricts your wire from feeding further down the torch.

Either way, you’re left with feeding issues, downtime and additional costs as you waste the torch length of wire each time a problem needs to be fixed.

How to Tension Your Wire

Method 1

To correctly tension your MIG wire (as different metal types can require different amounts of tension), follow these steps:

1. Start with a cold torch and feed about 50mm (5cm) hangs out of the end of the torch tip.
2. Decrease the tensioner arm by rotating anti-clockwise so that the wire slips (the rollers are spinning, but the wire doesn’t move) when the trigger is pulled.
3. Once the tension has been removed, you can then turn the tension level a half-turn clockwise to increase your tension, gripping the exposed wire between your thumb and forefinger with light pressure. Make sure you’re wearing gloves to do this, as the wire can get hot.
4. Pull the trigger while holding the wire. If it slips, repeat the process.

Keep adding tension until you can’t stop the wire with your fingers, and it feeds smoothly without slipping.

Method 2

The other way you can tension your drive rollers is with a wooden block. You’ll need a wooden block as it’s not a conductive material and your wire won’t try to weld to it. To tension your wire this way follows a similar process:

1. Start with a cold torch and feed about 50mm (5cm) hangs out of the end of the torch tip. Put a slight bend in the end of the wire.  
2. Decrease the tensioner arm by rotating anti-clockwise so that the wire slips (the rollers are spinning, but the wire doesn’t move) when the trigger is pulled.
3. Place your MIG torch roughly 20mm (2cm) above the block of wood and pull the trigger. The wire should start to curl against the wood until it starts slipping.
4. Turn the tension level a half-turn clockwise to increase your tension and start feeding the wire again. Repeat this process until the wire forms a 50mm (5cm) diameter circle against the block without the wire slipping.

Make sure not to put too much pressure on the wire, as it can flatten or deform it, causing feeding issues further down the torch. Too much tension on the wire will also cause it to birdsnest at the rollers if something restricts your wire from feeding further down the torch.