Aluminum Workshop: Are push or pull MIG welding guns necessary?

Q: I’m just starting to weld aluminum with gas metal arc welding (GMAW). Do I really need a push/pull gun—they’re expensive—or can I use a standard gun with a Teflon® liner and contact tips for aluminum?

A: This is not a yes or no answer. It really depends on the type and size of filler alloy you will use, as well as how long the torch cable needs to be.

First of all, why use push/pull torches at all? Standard torches for steel are push torches only. That is, the drive rolls are back at the feeder and push the wire through the torch cable and out the contact tip. But steel wire is relatively hard and strong compared to aluminum wire. If you try to push a small-diameter aluminum wire, especially if you try to push it a long way, it will tend to buckle in the torch cable or at the drive rolls (imagine pushing a rope along a table). In welding, we call that birdnesting. In any case, buckling will at least make the wire feeding irregular and may even stop it completely.

Enter push/pull torches. There are many types and all of them use a pull motor in the torch near the contact tip to help the push motor in the feeder. Some manufacturers make the pull motor the master and the push motor a slave. Others try to synchronize the two motors. In any case, the goal is the same, which is to provide some tension on the wire as it is fed to prevent buckling.

When You Need a Push/Pull MIG Gun

So when do you need a push/pull torch? First, if you need to feed any aluminum wire through a push torch, you should limit the torch cable length to 12 ft. or less. If you need a longer torch, you should use a push/pull torch.

Second, if you are trying to feed 0.035-in. wire, you need a push/pull feeder. If you are using 3/64-in. 5356 or another 5XXX alloy, it is very likely that you can get by without a push/pull torch. The same is true if you are feeding 0.062-in. 4043 or 5356. On the other hand, you will probably need a push/pull torch if you want to feed 3/64-in. 4043.

Just remember that any aluminum wire will feed best if you use a push/pull feeder and torch.