MIG welding is a very popular technique that is done by many welders. No matter how good you are or how long you've been welding, there are always tips that you can use to make your welds even better. Even a veteran welder has room to learn new tips!
When using an electrode you should keep 1/4 to 3/8 in stickout. If you are welding thin metals, then you need a smaller diameter wire. Thicker metals require larger wires and larger machines. Make sure that you check the machine's recommendations to know the welding capacity. Always use the right wire type for the base metal that you are welding. Steel wires should be used for steel, aluminum wires for aluminum, and stainless steel wires for stainless steel.
When using shielding gas, make sure you use the proper gas. CO2 is good if you're doing penetrating welds on steel, but it might be too hot if you are welding thin metal. For thinner steels, you should use a shielding gas that is 75% Argon, 25% CO2. If you are welding aluminum, then use only Argon. A triple-mix of helium, CO2, and argon is good for stainless steels.
There are two common wire types for welding steel. You can use a wire with AWS classification of ER70S-3 for any all purpose, economical welding you might need to do. If you have to work on rusted or dirty steel and need more deoxidizers, then you should use wires with a ER70S-6 classification.
It is vital that you maintain control of your weld bead. For best control, keep the wire pointed at the weld pool's leading edge. If you have to weld out of position – such as overhead welding, horizontal, or vertical – then you need to keep the weld pool small. This will allow you to have control of it and keep it from going everywhere you don't want it too. You should also use the smallest wire diameter that you possibly can.
Always match the wire size with the contact tube, drive rolls, and gun liner. Base it all off the wire size. The gun liner and drive rolls should be cleaned occasionally. Keep the gun nozzle clear of spatter and replace the contact tip if it is not feeding properly or is blocked. When you're welding, keep the gun as straight as you can so that the wire will feed correctly. If possible, steady the gun with both hands. When using a gun remember that a push gun technique will give you a wider bead and a bit less penetration. A drag gun technique will give you more penetration and a narrower bead.
