of the most important pieces of welding equipment you buy is your welding machine, the apparatus that provides the energy you use to make your welds and complete your welding projects. The machines come in many types, sizes, and prices to fit the needs of any welder. You can find inexpensive machines for small shops and projects, and expensive, more powerful welding machines for big shops and huge projects.
One of the most important considerations you need to keep in mind when you’re deciding which welding machine to acquire is the type of welding you plan on doing. Welding machines are available for all the various types of welding: stick welding, mig, tig, and more. (You can read more about the various types of welding in Chapter 1, and in the chapters that make up Parts 2, 3, and 4, where I dive into the details of each welding type.)
Welding machine basics
Following are a few welding machine considerations that you can keep in mind when you start thinking about the type of machine you want to buy for your shop.
❯❯ Power source: Be sure to purchase a welding machine that fits the electricity power source that you have available. Most household or small shops have only single phase electricity available.
❯❯ Current: Welding machines are also sometimes classified by the type of current they require. Some machines use alternating current (AC), which is an electrical current that flows back and forth at regular intervals in a circuit. Other welding machines use direct current (DC), which flows in one direction.
❯❯ Duty cycle: Welding machines are rated on duty cycles, which indicate how many minutes out of ten the machine can run continuously at its maximum amperage output. (Most welding machines have an output of at least 200 amps.) A welding machine’s duty cycle is based on the manufacturer’s recommendation. For example, if a 200-amp machine is rated with a 60-percent duty cycle, you can use it continuously (and safely) for six out of ten minutes when you have it set to produce an output of 200 amps. You can get a constant potential (CP) welding machine that maintains a constant flow of electricity, which results in a 100-percent duty cycle.
❯❯ Material type and size: Some welding machines can weld just a couple of different types of metal, and others can weld a huge range. You should also keep the size (thickness) of the metals you’re welding in mind. If you’re welding materials that are less than 3/18 inch thick, most welding machines are powerful enough for you. If you’re welding thicker metals, you may want to get a machine that can produce more amperage.
New or used: Which welding machine is right for you?
After you understand the different types and classifications of welding machines (see the preceding section), you need to decide whether to buy a new machine or one that has been used.
The advantages and disadvantages afforded by new and used welding machines are similar to what you’d expect for most other types of machinery or equipment. New welding machines have no wear and tear, and you can often buy one with a warranty that helps protect you if the machine (or part of it) happens to break down soon after you buy it. Plus, new machines come with instructions that can be extremely helpful for a beginning welder, whereas used machines often no longer have the directions. On the downside, new machines are almost always more expensive than comparable used models. New stick welding machines typically cost at least $400, and mig welding machines are often twice that amount. A brand new tig welding machine can run you $1,200 or even more, depending on the size and features of the machine.
If you want to buy a new welding machine, you can find them at larger hardware and home improvement stores, welding supply stores, and through online retailers.
Used welding machines can be a good route for people who are just starting out with welding and don’t want to sink a lot of money in a new machine. You can find quality used welding machines for half the cost of a new machine. The good news is that most welding machines don’t wear out or become ineffective unless they’re mistreated or maintained poorly.
If you want to buy a used welding machine, you likely have three options:
❯❯ Auctions: Equipment or general auctions in your area can be a great source for used welding machines. Call ahead or look through auction listings to see whether any welding machines are up for bidding.
❯❯ Welding supply stores: Many welding supply stores offer incentives for welders to trade in their used welding machines when they’re looking to buy a new machine. The stores then sell the used machines, sometimes after carrying out some basic maintenance or making any necessary repairs to the machine.
❯❯ Individual sellers: If you have friends or family members who weld, you may ask them if they have a used welding machine that they’re interested in selling in the near future. That’s a good situation because it means you know the seller and are probably familiar with how he treats his equipment. (Although if that relative is your reckless Uncle Bob, you may want to think twice.) You can also find individual sellers looking to sell used machines in classified ads or through online listings.
Stick welding machines
Stick welding is one of the most widely practiced welding techniques. (You can read all about stick welding in Chapters 5 and 6.) One of the biggest reasons for stick welding’s popularity is the fact that it’s inexpensive – in fact, the equipment used in stick welding is the least expensive of all the electric welding processes. Stick welding machines include the machine itself, as well as the welding leads, ground clamp, and electrode holder (see Figure 4-4). That’s all! If you’re going to be doing any stick welding and you want to get your hands on a stick welding machine, the big choice you have to make is whether you want an AC or DC machine.
❯❯ DC: DC stick welding machines give you a continuous flow of electricity, and they make it easier to produce good welds because they give you a higher level of control.
❯❯ AC: AC stick welding machines have one very important advantage: price. AC stick welding machines are the cheapest welding machines you can buy, and they require little or no maintenance. However, they can be a little harder to work with than DC machines, especially for new welders.
FIGURE 4-4: Typical stick welding machine.
Mig welding machines
Mig welding machines are more complex than stick welding machines and include a welding gun, a spool of electrode, an electrode feeding unit, a power supply, cables, hoses, and a cylinder of shielding gas. (Flip over to Chapters 9 and 10 for more on those terms and other mig welding details.) You can check out mig welders at your local welding supply store, and you can also get parts (like