Steven Robert Farnsworth - Welding For Dummies

Stick welding (also called shielded metal arc welding or SMAW) is an arc welding technique that has the distinction of being the most commonly used welding practice in the United States today. (More than 40 percent of all welding done now in the United States is stick welding.) The prevalence of stick is even stronger in construction; more than half of all construction-related welding uses stick. And the percentage is even higher in the maintenance industry.

Stick welding enjoys such popularity for three primary reasons. First off, it’s cheap. You can get into stick welding for less money than you’d spend to get started with tig welding. Secondly, stick welding is highly portable. The equipment is lightweight, and you can easily use it outdoors if the conditions allow it. Finally, stick welding is versatile. You can use it to work on metals with a wide range of thicknesses, and you can stick weld in just about any position that fits with your skill level.

Stick welding is great, but it isn’t perfect. One main reason is that it’s messy. Welding waste products, such as slag and spatter, get thrown around during a stick weld a lot more than they do when you’re tig or mig welding. Because of that, you have to plan on spending some time cleaning up your welds and weld area after you’re done stick welding. Another of stick’s imperfections is its speed (or lack thereof). You have to be pretty good at stick welding to do it quickly (especially compared to, say, mig welding).

You can read all about the stick welding process in Chapters 5and 6, but generally speaking, stick welding utilizes a consumable electrode with a solid metal rod in its core that melts down and forms part of the weld. Small globules of molten metal flow from the tip of the electrode through the electric arc to the molten weld pool. The electrodes have a coating of flux that protects the molten metal from impurities in the air that can contaminate the weld as it cools.

Mig welding is another arc welding technique. You may also hear mig welding referred to as gas metal arc welding (GMAW) or wire welding. Mig welding is becoming more and more popular, for several reasons. At the top of the list is the fact that most people find mig welding to be easier to pick up than stick and tig. Another big reason is the speed; done correctly, mig welding can be quite a bit faster than stick or tig welding thanks to its continuously fed wire electrode, which doesn’t require changing nearly as often as the stick electrodes used in stick welding. You can just keep right on welding without having to stop and change your electrode. Over the course of a welding project, that can definitely save you quite a lot of time.

Proponents of mig welding also cite the low amount of slag and spatter that mig produces. That makes for a more pleasant welding experience, and a much more pleasant cleanup experience. The low chance of distortion (unwanted changes in a piece of metal’s shape) is also trumpeted by those who love mig welding. Because the process is faster, you don’t need to apply as much heat to the weld area for as long, so the metal is less likely to bend and twist in nasty ways.

Of course, mig welding also has its downsides. For starters, mig welding equipment is more complex than stick welding equipment, so it’s quite a bit more expensive. The handheld part of the mig welding equipment (called the mig gun ) is often big and bulky, so it’s usually tough to mig weld in tight spaces. Mig welding also relies on the use of a shielding gas to keep atmospheric contaminants away from the weld area, so the process doesn’t really work very well outdoors (especially with any kind of breeze).

I save the details of the mig welding process for Chapters 9and 10, but generally speaking, here’s how it works: A wire feeder continuously feeds the wire electrode to the weld area at a speed you control. That produces a steady molten stream that you can easily direct however you want on the surface of the metal you’re welding. The weld is completely covered with a shielding gas (usually argon) to prevent impurities from fouling up the quality of the weld; you control the flow of the shielding gas to suit your project’s needs.

The last type of arc welding is tig welding, which is sometimes called gas tungsten arc welding or GTAW. One major advantage to tig welding is that it’s extremely clean. If you’re tig welding correctly, you may very well go through an entire project without having to spend any substantial amount of time cleaning up. Tig is also extremely versatile. You can use tig welding to work on a lot of exotic metals that just aren’t in play for, say, stick welding.

Tig welding has two big drawbacks. One is cost — you can definitely spend a pretty penny on tig welding equipment and supplies, even for start-up. The second drawback is lack of speed. You get a lot of precision out of tig welding, but you pay for it with time.

The tig welding process was originally developed in the 1940s to join aluminum and magnesium, but you can use tig welding to join all kinds of different metals. The big difference in tig welding is that it uses a non-consumable electrode that’s almost always made of tungsten. It also requires the use of a water- or air-cooled torch, which holds the tungsten electrode and is connected to the welding machine by a power cable. Like stick welding (see the earlier section), tig uses an arc of electricity to heat metal to its melting point, and you manipulate the puddle to join metals together. The major difference is that tig welding uses a tungsten electrode. You can read more about tig welding in Chapters 7and 8.

There’s more than one way to skin a cat, and there are more welding processes beyond the big three arc welding techniques (see the preceding sections). Here are a few to consider; check out Chapter 13for more info.

Brazing is unique among the welding processes because you can use it to join different materials (two different metals, for example). It uses gas rather than electricity, and the heat used in brazing surpasses 800 degrees Fahrenheit.

Soldering is a form of welding that uses (relatively) low amounts of heat. You can solder at temperatures below 800 degrees Fahrenheit. (That’s downright chilly when it comes to welding.) You can solder with gas or electricity, but the electricity you use in soldering isn’t the same as the type of electricity you use in arc welding. Instead, soldering uses an electric soldering iron that heats up and melts the filler materials you’re adding to the project you’re working on.

Oxyfuel/oxyacetylene welding is probably the most common gas welding process. You do it with a gas-powered flame that melts the base metal and any filler materials necessary to make the weld. The equipment used for this type of welding is the most portable and low cost in the welding world.

The need for skilled welders is huge right now, and it’s only going to continue to grow. New metal alloys are being created and used for a wide range of purposes every day. The industries that rely on welding are expanding rapidly across the globe, and the need for metals to be joined in skillful ways isn’t going anywhere in the near future. Welding is a versatile field that you can study in a number of different ways, from on-the-job training to education at a vocational or technical school. If you practice and develop your welding skills and work hard, you can more than likely make a career out of welding. And after you’ve been a welder for a while, you can very easily transition into a position as a welding supervisor, on-site supervisor, or inspector, just to name a handful of the possibilities.