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.

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.