Welding Guide - Welding Aluminum

Make no mistake, welding is a skill. The ones who can master it do it stunningly, not to mention they make a decent amount of money. But what about welding skills for work on your racecar? Anyone who has been around racing for any period of time has needed to do repairs at the track or in the shop and didn't have a welder when one was needed.

When I raced Karts, we once arrived at the track and after our first practice noticed that the main support that runs underneath my seat had broken. We searched up and down the pits only to find no one had a welder. We were definitely in a pinch, so we ended up taking a good-sized crescent wrench and duct taping the broken part of the chassis to one end of the wrench and the other end was duct taped to the rest of the chassis. We were actually pretty quick that night and a competitor came by and said, "So that's your secret! I'm going to have to break out a hacksaw and cut my support in half."

With a welder on hand, we could have easily welded the support bracket back together and not had any problems. Welding steel can be pretty basic. It usually requires a MIG welder and a steady hand. Problems do sometimes arise, as you can burn through the steel from having too much heat applied.

Welding aluminum, however, can be very tricky and difficult. Also-and this is very important-TIG welding can actually burn you similar to a sunburn, make you see some strange things, and even cause you to go blind. Make sure that you do not have any exposed skin when you are TIG welding, and wear thick leather gloves and a good welding mask.

Most MIG welders have a converter kit that allows you to put in a new spool of wire and weld aluminum. It works fantastic if you have a large area to cover or if you are welding on thicker aluminum. But, most of the time, you will be using a TIG welder for aluminum because it is easier to control how quickly the aluminum heats up and this is vital for the thinner pieces of aluminum. TIG welding produces much cleaner welds without the spatter that is involved with MIG welding. TIG also uses 100 percent argon gas instead of an argon and carbon dioxide mixture that you would normally see on a MIG welder. The more pure the argon, the better the weld.

Chuck Gafrarar, of Mooresville, North Carolina, owner of Chuck G Fabrication, is known around the racing world as one of the best fabricators in the business. He builds USAR Hooters Pro Cup, ARCA, Busch East, and Late Model bodies for different teams, not to mention that he builds all of the Penske Racing show cars.

"TIG welding is extremely hard in the first place, but the hardest part is learning how to control the heat that you are applying to the aluminum," says Gafrarar.

TIG welding employs either a foot pedal or a dial on the torch that controls how much voltage is being sent to the aluminum. Too much voltage and it will burn through the aluminum. The trick to welding very thin pieces is to "sneak up" on the aluminum by using very little pedal at first, in order to warm up the aluminum. Keep the torch at a distance and slowly apply more pedal, moving the torch closer to warm up the aluminum at a steady pace. It's important to keep the torch about 1/4- to 1/2-inch away from the aluminum. If you were to push the pedal all the way down at the start of the process, you would blow a hole right through the aluminum.

The aluminum to be welded will require cleaning. I suggest an industrial cleaner that can evaporate pretty quickly, one that will pull up the grease that may be on the aluminum. For example, something like SCAT Wax and Grease Remover by Transtar Autobody Technologies or First Klean by Dupont.

TIG welding is different from MIG welding because it uses tungsten as an electrode to heat up the aluminum. The significance in this is that the tungsten is designed to never actually touch the aluminum. Again, the torch needs to stay about a 1/4-inch to 1/2-inch away from the base metal. If it does touch, you will have to pull the electrode out and grind it down because the aluminum will actually stick to the tungsten and create very inconsistent welds.

When the aluminum is heated up and a small puddle of liquid aluminum has formed from the base metal, the welder dabs a rod of aluminum onto the outside of the puddle. This will pull a droplet of aluminum off of the filler metal and into the puddle, allowing you to keep the weld moving strong and keeping your puddle the right size.