TIG welding is one of the best options for welding a roll cage, and in the case of the National Hot Rod Association (NHRA), it is actually the type of welding that is sanctioned and required for the construction of chromoly roll cages.
So how do you TIG weld a roll cage? Here are some tips on how to perform this weld job more effectively:
- Weld the cage up in place
- Tack the cage down for stability
- Weld vertically and upwards
- Watch heat application and filler selection for quality bead color/configuration
- Keep torch and filler travel consistent
- Keep filler road on the forward edge of the weld pool
- Use remote or finger controlled TIG for better precision
TIG welding is the metalworking technique recommended for roll cage safety, and in many competitive circles, it’s a requirement, but why is TIG favored over MIG welding in roll cage construction? Read on to find out more about TIG welding roll cages and how to do it.
Is TIG Welding Required for Roll Cages?
TIG welding is not required for all roll cages, but those that are being used on vehicles involved in competitive sports are often required to be TIG welded as part of a safety standard for the construction of competition vehicles.
This is because TIG welding is considered a stronger, more precise weld than MIG welding, and is a safer choice for chromoly. MIG welding involves a wider fluctuation in temperature, while TIG welding ensures an even temperature throughout the weld.
Chromoly, the predominant metal used in roll cages, cracks when it undergoes large fluctuations in temperature, and because roll cages have to be able to withstand heavy impacts to protect the driver inside them, this threat of breaking is a massive safety issue.
MIG welding is sometimes used on roll cages that are constructed with mild steel, which is heavier than chromoly. However, MIG welding adds even more weight to the roll cage due to deposition during the weld, which can be unsuitable for race car welding.
How to TIG Weld a Roll Cage
When TIG welding a roll cage, there are several factors of the weld that you need to take into consideration before you get started. Here are some of the things you need to think about in order to accomplish a successful TIG weld on a roll cage:
- Fitting the roll cage: It is recommended that you weld the cage up in place on the vehicle rather than try to weld it at a bench and then attach it afterward. This is the only way to make sure that the roll cage fits correctly.
- Tack the cage down for stability: To make sure the roll cage stays in place, perform tack welds at the corners of the roll cage where it attaches to the vehicle to give it stability. Once these tack welds are performed, the rest of the roll cage can be welded more easily.
- Weld vertically and upwards: Welding upwards and vertically makes it easier to see the weld pool and makes it easier to control the TIG foot pedal while you move the filler rod and torch simultaneously.
- Check bead color/configuration: It’s a good idea to do a few test welds and make sure you’re happy with the look and color of the bead your filler rod is producing before welding on a
Note: Bead color and look is determined by the application of heat and the metal filler. Hazing and discoloration can occur as the result of too much heat, or the filler metal selected.
- Keep torch and filler travel consistent: One of the most difficult things to learn about TIG welding is keeping steady travel speed on both the filler metal and the torch at once. This problem is compounded when you are welding vertically, so doing some practice runs can help you get a feel for the weld and lead to a better end result on the final run.
- Keep filler rod on the forward edge of the weld pool: Instead of dipping the filler metal into the center of the weld pool, keep the filler rod on the very outer forward edge, and only add as much filler to the pool as the diameter of the filler rod. This will help you keep control of the weld and prevent both drips and contamination.
Pulse Welding a Roll Cage
Another good option for TIG welding a roll cage is to utilize a pulse welding technique, such as the technique demonstrated in this video. There are two types of pulse welding–slow pulse welding (1-2 pulses per second typically) and high-speed pulse welding (more like 30 pulses per second).
Higher pulse rates tend to cause eye strain and increased fatigue, which is already an issue when TIG welding vertically. So sticking to a slower pulse can be advantageous when constructing a roll cage.
Pulse welding is a good choice for roll cages for the following reasons:
- It keeps the temperature down: One of the reasons MIG welding is not allowed on competitive level chromoly roll cage tubing is because chromoly becomes brittle when exposed to large temperature changes. Pulse welding helps keep the temperature both lower and more even.
- It allows for more control: Setting the TIG torch to, for example, a two-second pulse, allows the welder to get into a rhythm of traveling both the torch and the filler along the line of the weld. This flow results in a more precise, more aesthetically pleasing weld.
If a TIG torch does not come with a pulse setting, pulsing can also be accomplished manually via input in the foot pedal. It takes significant amounts of practice to do this and achieve a consistent look in the resulting bead, however.
Remote and Finger Controlled TIG Setups for Roll Cage Welding
Remote and finger controlled TIG torches can make constructing roll cages significantly easier, as you’re not having to operate the pedal with your foot at the same time as you’re moving along the weld and placing filler with one hand while holding the torch with the other.
This kind of balancing act can be difficult enough to accomplish at the welding bench without throwing in the added stresses of having to weld vertically and on angled materials.
Once the pressure of having to maintain the foot pedal along with the manipulating both hands at once is removed from the welder, the result is typically better-looking, stronger welds. Since roll cage welds are responsible for keeping drivers alive, the strength of the resulting weld is absolutely crucial.
TIG Welding Roll Cages: It Helps to Have Assistance
Roll cages can be unwieldy to first position before a few tacking welds are put into place, so it can pay off to bring in a second set of hands to help hold the roll cage steady while you lay down those first stabilizing beads.
Another way that having an assistant can help with TIG welding a roll cage is by having an assistant control the foot pedal while you perform the weld. This removes the need for a remote or finger controlled TIG setup, and once you get used to issuing pedal requests, the work can be performed very efficiently this way if you have a good partner in the shop.
TIG Welding Roll Cages Is Important
While MIG welding is sometimes used on mild steel roll cages, TIG welding is really the strongest form of welding you can use on a roll cage, and they should be constructed with safety as the watchword. This is exactly why it’s required at a competitive level.
Luckily with just a little practice and the right tools, anyone can weld a roll cage with a TIG torch that is not only strong but looks good, too.