Monday, November 30, 2020

Advice to a former student who wants to learn to weld

The phrase "MIG and TIG" is misleading, although it alliterates nicely and so somehow stays in the lexicon. There are actually five choices for welding steel, of which TIG is the least useful under normal circumstances. In order of usefulness: 1) arc-welding, AKA "stick welding," using flux-covered welding rod, where the flux prevents oxidation of the molten metal; 2) MIG or "metal inert gas" typically using argon gas as a shield to prevent oxidation; 3) "flux-core" welding, typically using the same equipment as MIG, only without the gas; 4) oxy-acetylene welding and brazing that uses a gas torch and filler rod; and lastly 5) "tungsten inert gas" or TIG which uses separate welding or "filler" rod and an expensive tungsten electrode, needs two hands at all times and so is horrible for vehicle or boat work, but can more easily be adapted to metals other than mild steel. Most welders only need the first three. In a pinch you can do 95% of what you need to do around a workshop, farm, or shop with a stick welder, although having the other types makes life much easier. If you can learn to weld with a stick welder, you can easily pick up the other types in very short order, so it's best to start with stick welding, then add MIG and flux-core, which often use the same welding sets these days anyway. In forty-plus years of welding I've never needed TIG, and I've only used oxy-acetylene welding equipment for heat during other mechanical procedures, or for brazing, not for actual welding. I regularly use all of the other three. I use stick for heavy steel fabrication and cutting, flux-core for most vehicle welding, and MIG for some bodywork when I need an especially good finish. I also have an aluminum "spool" adapter for my MIG/flux-core welder, and cast-iron rod for my stick welder, a classic Lincoln-Electric "tombstone", negating most of the need for the other two types of equipment. The best way to learn to weld is to get shown the basics by someone, then practice. There's no shortcut, and in fact, all you'll do different in a class is learn the theory a bit better, then get shortchanged on the practice because there isn't a vo-tech or community college in the country that can afford to let you practice as much as you actually need to. And a certificate won't do you any good if your welds fall apart because you can't practice. You can pick up a cheap but functional stick welder at Harbor Freight for a Benjamin, less than the tuition at the vo-tech AND you'll then have your own welder. It will come with a cheap and nasty but functional welder's hammer. You'll need to buy some one-eight mild steel rod and find some scrap steel to practice on. A good light-operated welding mask, good welding gloves AKA "gauntlets", a long-sleeved coat made of something that doesn't burn or melt, and a place to work outside that won't catch fire are also needed. A hand grinder with a selection of heads (cutting, grinding, steel brush wheel) and googles are also very helpful, but optional at this stage. Work outside because fumes are nasty. Have an ABC-type fire extinguisher handy. Then practice, practice, practice. The best advice I ever got for welding was "focus on the molten pool." The pool of molten metal is all-important and your ability to put that pool where you need it and to shape it makes you a good welder or not.

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