In racing, welding is clearly one of those things that is inescapable for those who have shops and build or do repairs on their race cars. Since race cars are literally held together by welds, it stands to reason that the serious racer should know (or want to know) some things about the subject. While every racer may not actually do welding, knowing something about it would be smart, if only to be aware if someone else is handling the job right.
With that in mind, we decided this would be a good time to take another look into that subject. Much has been written on welding, and much of that information has been on the pages of Circle Track. Although we have presented some of these basics before, with the season in full swing, it seemed an appropriate time to reinvestigate welding basics.
Roger Pierce, master welder for Jasper Motorsports
As a refresher, we decided to look primarily at the basics of MIG operation, since this is the overwhelming type of machine that Saturday-night racers are likely to use. This kind of system is commonly found in shops and is the basis for fabrication welding of chassis tubing, mild steel, chromoly tubing, and the like. We will also discuss principles of TIG operations as well.
Getting to the heart of welding basics, we spoke with Roger Pierce at Jasper Motorsports in Mooresville, North Carolina, the home of the #77 Winston Cup car driven by Robert Pressley. Pierce has been doing welding for 23 years-specifically in racing for 12 years-so he had the credentials we were looking for to fill us in on this theme.
It is important to note that while at the Jasper Motorsports shop, we were exposed to Lincoln Electric machinery; however, there are many sources of fine welding equipment, such as ESAB, Miller Electric, Daytona Mig, and others. Each maker may have differences in the way each respective machine is operated, but the basic principles presented here share common ground among the different makes.
MIG welding units are the most common types of welding equipment used by the weekend warrior. An example of this type of machine is the one pictured here. This 110-volt MIG machine supplies enough welding power for a good weld on materials up to 3/16-inch thick. Wire speed and voltage are controlled by the dial settings on the front of the machine. For most of the materials welded with the use of this machine, a 20- to 30-volt setting is usually within range to get the proper bond.This device is generally used for sheetmetal of 30, 26, and 24 gauge (the lower the number, the thicker the material). The 220 higher voltage machine is required for anything above 24 gauge because of the higher amperage output. For thicker materials, a higher penetration is required, and without higher voltage and amperage range, that will not happen. As a general rule, the desired penetration for a weld is at least half the thickness of the material. Less than that may produce an unsatisfactory bond. More can cause a blowout, which is when the material blows through the underside of the welding site-this is also undesirable.
This larger welder is a 220-volt MIG machine and is used for materials starting at 1/4-inch thickness. This type of welder can provide good bonding characteristics on materials as much as 3/8-inch thick. The higher voltage is required at this thickness of materials for proper penetration and bonding qualities. As a reference point, a 220-volt welder is put into service when 16-gauge sheetmetal is used. As has been pointed out, when the thickness of materials increases, higher voltage and amperage are required for a good weld, so for 1/4-inch thick and more, a 220-volt machine is required.As seen in this shot, the wire medium is on a spool, which is fed through the wire lead gun. Like its smaller cousin, the dial settings on the front of the machine regulate the wire speed and amperage range. Setting the amperage and wire speed is a learn-as-you-go type of thing, but there is some information on these subjects is provided by manufacturers. They generally supply some guidance for amperage settings in relation to the material being welded. In this example, a handy chart is affixed to the inside of the welder cover.
Moving on up the scale of welding machines is this heavy-duty industrial version. It is a
TIG and MIG Basics 101
Before we go into some of the operational basics, we will cover just a little of the definition side of this discussion. Since we will talk about both MIG and TIG welding, a definition of what they mean is in order.
MIG stands for Metallic Inert Gas and means that the wire used in the machine is of a mild steel makeup, and an inert gas mixture of carbon and argon is used in the process to ensure a weld.
As a quick explanation of the process, the steel wire is electrified, creating an arc that superheats both the wire and the host material so the wire and materials bond-thus providing a weld. The gas is pressurized to the site of the electric arc so that any effect of the earth's atmosphere is removed, which provides a medium for the correct bonding process to be made. MIG welding is done on steel and requires DC (direct current) capabilities.
TIG stands for Tungsten Inert Gas Welding, and the process is similar to that of MIG, except that the medium is Tungsten steel and is done in an environment of pure argon gas. TIG machines are commonly used to weld aluminum because they can be operated in an AC (alternating current) setting, which is required to weld aluminum.
Now, with a little of the refresher out of the way, let's take a look at some of the basic principles of welding. We will also look at the fundamentals of machine operations and the kind of work they can produce.
On MIG welding units, the wire lead gun (shown) houses the mild steel wire that is fed to
With the cup removed, the opening that supplies the inert gas to the wire gun can be seen.
Gas pressure is regulated by this gauge mechanism. The gauge on the left displays the amou
MIG welding is largely used for tack-welding in the race car fabrication process. Tack-wel
Although tack welds are commonly done with a MIG, long beads are also created with this ma
It goes without saying that welding can be dangerous if it is not done with safety equipme
This is a TIG welder, which is used for welding mild steel, stainless steel, and aluminum; it uses tungsten as the arc medium (material inside the lead gun). This kind of welding requires the use of welding rods, while MIG does not.When mild steel or stainless steel is bonded using this machine, it runs in a mode called DC straight polarity. Because the polarity is different than the MIG welder, carbon is no longer required as one of the inert gasses, so the welding is done with pure argon. Aluminum welding is accomplished in the AC mode, which is required for bonding aluminum.No matter what material is being bonded, the same principles of power settings, based on the thickness of the material, apply to both TIG and MIG. According to Pierce, there is no real difference in the strength of a bond between TIG and MIG, but the weld has more concentrated heat in a smaller area in the TIG.TIG-welding is not for the amateur, and this is one of those things that a racer can move up to. But, for the Saturday-night racer, this machine will not likely adorn the shop floor space because it would probably bust the budget big-time.
This is a stick of tungsten, which is the arc medium for the TIG welder. The point is shar
When aluminum is welded, the point of the tungsten is required to be in a radius, which ap
Aluminum welding is one primary use of a TIG welder. This is what a good aluminum weld loo
There are a number of manufacturers who produce economical and efficient welding units for
1821 Holsonback Dr.
Daytona Beach, FL 32117
411 S. Ebenezer Rd.
Florence, SC 29501
Lincoln Electric Co.
22801 Saint Clair Ave.
Cleveland, OH 44117
Miller Electric Manufacturing Co.
1635 W. Spencer St.
Appleton, WI 54912