welding mild steel tubing for rollcage

[Steve Kurey]

Andy I am building a SCCA ProRally car. The cage calls for 1.75"x0.095" mild steel seamless tubing. What is the best process to weld it together? Is MIG welding and if so what gas combination and wire thikness or is TIG welding better? What is better TIG or MIG? And what Miller Machine do your recommend that we can take to the rallies and run off a generator in case we have to weld somthing a the rally?

Thanks Steve Kurey

[ASKANDY]

Steve,
Most of us MIG weld the chassis together. A MM-210 is the most popular unit with the race teams here. .030 ER70S-6 wire and 75/25 Arg/Co2 gas. For the massive hits these guys take on the superspeedways, MIG welding has done the job just fine. There are a couple of teams that do TIG. Penske and Yates prefer TIG. Keep in mind that TIG will easily double or triple the time it takes to weld.
A good unit to run off a generator would be the MM-175 if you have 230Vac available. If you only have 115, the MM-135 will have to be your choice.

[Kevin Disney]

Steve,

Remember that weld preparation is just as important as the welding process. If you don't get adquate penetration because of improper joint fitup, it doesn't matter what process you used. Take the time to get the joint right before you weld. Either MIG or TIG will give you an acceptable weld, just depends on how much time you want to spend welding.

[jessp]

Steve,
A good unit to run off a generator would be the MM-175 if you have 230Vac available. If you only have 115, the MM-135 will have to be your choice.

Just how large a generator would you need to run MM-175? I have a 4000 watt but have not tried it out with this machine.

thanks