Mig Welding 101

MIG (metal inert gas) welder, aka gas metal arc welder (GMAW), was once a not-so-common sight in home garages across the country. But today, with technology rising and prices dropping, they are within most do-it-yourselfer's reach. With this being said, there are still plenty of fancy, highfalutin MIG machines that cost a pretty penny, but we'll pay no mind to those since we have no use for them while working on our classic trucks. Even though it is fun to get carried away and pipe dream about the biggest and baddest welding machine that has tons of amperage and can weld thicker material than your neighbor's welder, it's more than you'll ever need and money wasted. Many of us don't even have 220-volt hookups in our garage, which limits the type of machine you get--but that's not to say you can't have a machine that'll do most anything you'll ever need it for.

Let's start off by saying that even though setting up your machine for flux-core or self-shielding wire is less expensive initially, it's better reserved for building bridges and battleships since flux-core doesn't use a shielding gas, which could blow away in windy conditions. While flux-core welds a little hotter, it also leaves a crust or slag layer on the weld, which needs to be chipped away afterward much like ARC or stick welding. There's no sense in making it more difficult to get a nice looking weld for what we're trying to accomplish.

MIG welding on mild steel is the easiest welding process to learn, thanks to its all-in-one welding gun that spools out the solid carbon-steel wire, while dispensing a mix a of argon and carbon dioxide shielding gas from an external bottle, all in the squeeze of the trigger. Because of this almost one-handed operation (although it's best to use two hands for stability), it makes getting into tight or awkward spaces (in or under a truck or anywhere else) easy. With TIG welding, you have a foot pedal that controls amperage, the torch in one hand and filler rod in the other, which can make for a tricky situation.

Aside from buying a MIG machine that suits your realistic and practical needs, getting the proper safety gear is next on the list since we are dealing with excessive amounts of heat, light, sparks, and voltage. First up is a helmet--aka hood. These range from mild to wild in function, price, and appearance. A standard flip up-style helmet is cheap and does the job, but is awkward for beginners to get used to, although there are those that learned on them and prefer them to auto-darkening helmets (like myself). There are many automatically darkening helmets, which are easy to use and cut one more step from the welding process. They may help you start your weld where you want it, but obviously these cost more. No matter what, get a helmet with a large lens in it so you can see what you are welding easier. While MIG welding, wear thick clothes like jeans and a jacket or thick long sleeve shirt since it does throw sparks, many of which turn into little "berries" that can burn through thinner materials. If you plan on doing lots of overhead welding, you may want to look into getting a jacket made just for welding. If and when you weld in a short sleeve shirt, be sure to buy a pair of welding sleeves to protect your arm from sparks, berries, and most importantly, from sunburn. If you weld without a helmet, you WILL burn your face, eyes, arms, and possibly other exposed skin. You'll also need pair of thick leather gloves for the same reason you need to dress appropriately: heat, light, and sparks. Because of this, MIG-specific gloves are much thicker than those made for TIG welding, but both versions have a long cuff to help protect your arms until your sleeves take over. If you find yourself welding hunched over and close to your feet, you may want to put a pair of leather boots on, too.