Welding Equipment Guide - Metal Mania
Welding Basics You Need To Know Before You Shop
Welding Equipment Guide
Basic Welding Overview
The more you accomplish on your own in your home shop/garage the more satisfaction you get out of your classic Ford project. It's safe to say that most of you reading this magazine probably have enough handtools to get the job done. Specialty tools, on the other hand, usually only get purchased if there is a great bargain or if you know you'll be using the tool more than a few times. It's rare we see people buy a complete HVLP painting system just to paint their own car (though we have seen it). Now welding equipment, on the other hand, is something we feel is a sound investment for the home shop. Even if you only plan to build one classic Ford project, the labor involved in typical rust repairs (floors, fender apron, and so on) isn't overly complicated, but is time consuming, which turns into big labor bills. Handling these repairs yourself with a home MIG welder not only gives you that sense of satisfaction from working on it yourself, but will save you plenty of money in labor bills. Furthermore, the welding equipment will come in handy for many home projects (we've fixed trampoline frames, bicycle frames, patio furniture, exhaust systems, lawn tractors, and more over the years with our home welding equipment).
What we've compiled here for our readers is an overview of welding types, equipment, and more to get you started down the path of home welding projects. We encourage you to pick up reading materials on welding at your favorite book retailer. You can also find instructional videos from the major welding equipment manufacturers, online tips and FAQs, as well as newsletters you can sign up for that are delivered directly to your email inbox. Finally, local community colleges and technical/vocational schools offer welding classes where you can get hands-on training, often with similar home shop based equipment, which will give you the confidence you need to tackle most any project. So check out this welding equipment guide, do some research on your own, and even visit a local welding equipment retailer to try one out and see what's best for your project needs, budget, and shop size.
Welding is a fabrication process that joins separate pieces of metals. This is accomplished by partially melting the juncture of the work pieces while adding metal to form a pool of molten material, which then cools and solidifies to become a very strong joint. In the types of welding we are interested in, electricity is used to create the heat. Other welding methods, such as brazing or soldering, use heat obtained from an external source such as a torch flame or an independently heated soldering gun tip. Brazing or soldering creates a joint where the bond is, to some extent, external to the pieces being joined and the joint is usually not as strong as the material being used. This is because during brazing or soldering the materials are not completely melted and mixed together. The three types of arc welding we are going to look at create a bond that is as strong as the material being joined. All three types of welders have a principal function in common. They transform high voltage, low amperage primary power into low voltage, high amperage secondary or welding power. They do this through two sets of windings or coils of copper wire inside the machine that are wrapped around steel plates.
On any type of arc welding, the molten joint must be protected from atmospheric contamination and this is accomplished either by a coating of flux contained on or in the electrode or by an inert gas such as Argon that is applied to the surface of the weld while it is being created. In stick and flux-cored wire, welding the flux leaves a coating of slag, which must be chipped off once the weld has cooled. All arc welding processes involve a welding power source and some means of completing an electric circuit between the electrode and the part being welded. While different welding processes share some things in common, each process creates the finished product in a unique manner.
The three types of welding that we are concerned with include stick welding, MIG welding and TIG welding. While all three types of welding are closely related in principle, each process offers advantages in certain applications. For general repairs, a stick welder can be a good way to go. One reason is lower cost. Stick welders start at about $400 and go up to around $2,000 for a home- or shop-sized unit. MIG welders are more popular in automotive applications and will weld aluminum as well as steel. You can do cleaner work with a gas welding set up because there is no slag or residual material creating a mess and requiring removal. MIG welding setups start at about $800 and can go past $2,500 in cost. With a TIG welder you can do even finer work on thinner metals because not only is residual slag absent but the temperature of the welding spark can be more accurately controlled and the welding material is added by hand. TIG welders cost a little more and start around $1,200 and go up past $3,000.
Choosing which of these three types of welders is best for work on your classic Ford project depends on what you're going to be doing. Before you go out and lay down your money you should ask a few important questions. One important consideration is input power requirements. You'll need to know what voltage is available in your shop or garage. Is it 110 or 220 volts? Some home-use or light- duty welders work off of 110-volt current. Most other types use 220-volt. What are the amperage draw limitations on your circuit breaker? Circuit breakers have both voltage and amperage ratings that limit the amount of current that can flow through them. The standard household 115V outlet in your home likely has a 15 or 20 amp rating, while your 230V dryer circuit has a 30 or 50 amp rating. Knowing the rating of your circuit breaker is important, because weld-ers have minimum power requirements. If you meet the minimum requirements, you'll be able to weld. However, an undersized circuit breaker will limit the welder's top output. Further, if your welding power demand exceeds available input power, you'll trip the circuit breaker. Don't forget to factor in the electric loads of other equipment you'll need to run at the same time as the welder. To determine circuit size required, examine the welder's spec sheet and look for the amps input at rated output figures.
Before you purchase a welder it's important to consider the thickness of the metal you'll be welding on because the amperage required to successfully accomplish the weld varies. The thicker the metal you intend to weld, the greater the amount of amperage required. The material thickness and the current carrying capacity of the electrode determine the amperage at which you weld. As a general rule of thumb, you need one amp of power for every 0.001-inch of mild steel. For example, to weld 1/8-inch (0.125-inch) mild steel in a single pass, you need approximately 125 amps.
The type of metal you'll be welding will also change your equipment needs. For example if you're going to be welding steel some of the time and aluminum at other times, you may wish to add a spool gun for the aluminum welding. More precise control is the result and it eliminates having to unload the wire used with steel welding from the machine when running a second type of wire. What upgrades and accessories are available for the machine you selected? Are the machine's size, weight, and portability important to you? These are all things you'll need to consider. Inverter-based welders are also available. They require much less primary power than conventional welders because they feature special circuitry. While an inverter welder will cost more, you could actually save money if you avoid the need to rewire your garage, barn, or shop.
Besides amperage capability range, the machine's performance is also evaluated for continuous rated output, which is expressed in terms of its "duty cycle." The duty cycle is the number of minutes out of a 10-minute period that a welding machine can operate at the rated output. This standard helps buyers make a direct comparison between welders. To better understand how duty cycle ratings are applied specifically let's look at two different sizes of welders. A typical machine for home or shop use might have a total output range of 30 to 140 amps. If it were rated for an output of 90 amps at a 20 percent duty cycle that would mean that it can weld continuously at 90 amps for two minutes and then must cool down during the remaining eight minutes to prevent overheating. A second example might be a heavier semi-industrial-type unit that's also popular for more serious personal users. If it has 30 to 300 amp welding range and duty cycle of 40 percent at 250 amps it can weld continuously at 250 amps for four minutes and then must cool down during the remaining six minutes to prevent overheating. As welding output decreases, duty cycle increases. For example the 40 percent duty rating at 250 amps would increase to a 60 percent duty cycle when welding at 200 amps. Ambient temperature also impacts duty cycle. For example, if a machine achieves its rating at 104 degrees Fahrenheit then the machine becomes de-rated to some extent when welding at ambient temperatures of greater than 104 degrees.
Stick welding is also known as shielded metal arc welding. Stick welding is a manual arc welding process that uses a consumable electrode, or stick rod, that is coated in flux. The filling metal material is obtained from the electrode core, while the flux coating produces shielding gas and a layer of slag, both of which protect the weld from atmospheric contamination.
The second type of welding we are concerned with is commonly called MIG, or gas metal arc welding. It is also sometimes referred to as wire welding. MIG welding is a semi-automatic process that creates an arc between a continuously fed wire electrode, which provides the required filler material, and the part being welded.
There are two types of MIG welding. A specialized machine can do both types. In one, externally supplied shielding gas from a gas cylinder protects the molten weld puddle from contamination. The shielding gas and wire are both fed through a MIG "gun" and they begin flowing when the operator squeezes the trigger. A big advantage to gas-shielded welders is that there is no residual coating because the gas dissipates after the procedure is completed. Because in standard MIG welding the weld is protected from contamination by a continuously fed protective gas there is no slag to chip and far less smoke. The downside of gas-shielded welders is that they can't be used outside in windy conditions because the wind can disperse the gas before it provides the required protection.
MIG welding can also be accomplished using one of two types of flux-cored wire. In one case, instead of a gas being applied from an external source a flux contained within the tubular electrode wire core creates the shielding gas when heated by the arc. The self-shielded gasless-type of MIG welder does not need any secondary shielding gas and they are commonly used for do-it-yourself or home service. The other type is the gas-shielded flux-cored wire MIG welder. It requires an externally supplied shielding gas. Both types of flux-core wire cover the top of the weld with a hard slag coating that must be chipped off prior to painting or subsequent weld passes. Another advantage of MIG welding is that it is the easiest welding process to learn.
MIG welding using flux-core wire works as well as stick welding on dirty or rusty material. In addition, self-shielding gasless wire can be used for welding outdoors. The use of self-shielding wire increases portability as there is no gas cylinder to haul around. MIG welding using flux-core wire offers deeper penetration when welding thick sections and a high rate of metal deposition allows the job to be completed faster.
The third type of welding that we are concerned with is TIG or gas tungsten arc welding. TIG welding process uses a non-consumable tungsten electrode and a shielding gas that protects the welding area from contamination. The arc comes off the point of the tungsten to melt the base metal while the operator manually adds filler wire in a technique similar to brazing. TIG welding is the type of welding that offers the most flexibility. Unlike MIG or stick, TIG welding lets an individual operator control heat input while working using a remote foot pedal or fingertip control. Hence, welding on thin materials is more easily accomplished and with less distortion.
The TIG process welds all metals with just a single gas, usually argon. TIG welding provides the highest quality detail work, and very aesthetic weld beads can be created. TIG welding also produces the least amount of sparks or spatter. Both flux-core and stick welding use an electrode with positive polarity and the work is grounded. Both use a constant current design. In gas-protected MIG welding and in TIG welding the electrode has negative polarity. As we have already noted TIG welding uses variable current.
Different electrodes, base metals, and welding processes require different shielding gases. For all TIG applications, use 100 percent argon. For all MIG aluminum applications use 100 percent argon also. For MIG welding on stainless steel, a "tri-mix" blend should be used. Tri-mix consists of 90 percent helium, 7.5 percent argon, and 2.5 percent of carbon dioxide. As you become more involved with different alloys or procedures, the shielding gas requirements change, so you'll need to research which gas combination will work best for your specific jobs before you proceed.
One final thing to think about is welding safety. Arc welding safely always requires proper safety gear to protect you from the harmful sparks, heat, and ultraviolet rays that can burn skin and eyes.
Sometimes before you can weld you need to be able to remove other material before you can begin. For doing this it's hard to beat plasma cutting. Plasma is an ionized gas that conducts electricity. Plasma is created by adding energy to an electrically neutral gas. In this application the gas is compressed air and the energy is electricity. The more electrical energy added, the hotter the plasma arc becomes. Plasma-arc cutting machines control this powerful energy by constricting the arc and forcing it through a concentrated area called the nozzle. By increasing air pressure and intensifying the arc with higher amperage, the arc becomes hotter and more capable of blasting through thicker metals.
As you can see from this photo, a plasma cutter makes short work of the 1/4-inch thick steel framerail. Plasma provides numerous advantages over other common cutting processes. The plasma process cuts any type of electrically conductive metal including aluminum, copper, brass, and stainless steel. Plasma cutting produces a narrow and more precise cut while sawing or chopping takes a long time and will typically leave a rough edge. Plasma cutting is fast, clean, and leaves a nice straight edge. It also offers gouging and piercing capabilities.