When welding an open-root butt joint (uphill) how best to control the keyhole in MIG?
With stick, you can whip the electrode forwards just long enough to let the pool cool and stop the keyhole getting too big and running away. But how do you control the keyhole in MIG welding? If you similarly whipped the torch forwards along the root, there's the strong chance that wire will squirt through; you could whip along one edge of the root, but that would give an uneven root. I have tried momentarily releasing the trigger for a fraction of a second and that works but I'm not sure if it's good practice.
I've also seen how the voltage really drops as you push the torch really close; that would reduce the heat input. Is that therefore a practical technique to use to regain control before pulling back to a more normal stickout?
I'd really appreciate any tips and advice on this.
Martin
With stick, you can whip the electrode forwards just long enough to let the pool cool and stop the keyhole getting too big and running away. But how do you control the keyhole in MIG welding? If you similarly whipped the torch forwards along the root, there's the strong chance that wire will squirt through; you could whip along one edge of the root, but that would give an uneven root. I have tried momentarily releasing the trigger for a fraction of a second and that works but I'm not sure if it's good practice.
I've also seen how the voltage really drops as you push the torch really close; that would reduce the heat input. Is that therefore a practical technique to use to regain control before pulling back to a more normal stickout?
I'd really appreciate any tips and advice on this.
Martin
