Down here in Tampa a lot of cars are made of EMT conduit, especially the Robinson cars (Meangreen). But my teacher is very hesitant with it because it is galvanized and creates toxic fumes when welding, but it can be MIG welded. But aluminum is also popular but we don't have the money for a TIG welder or the skill. So what other materials are used in car that can be MIG welded? What is used at the schools in the NW?
Middleton High School, Tampa
"If you ain't first, you're last" -Reese Bobby
I can say I have an aluminum framed car. Before the new year, my car turned seven years old. In the entire time I've driven it I've never had something break on the frame due to a weld issue. The majority of the frame was welded together using a spool gun while the critical areas for the front steering and where the rear wheel sits was done using a TIG. The other thing to keep in mind if you are planning to build a alloy frame car would be make sure you've got enough bracing throughout the frame. If you don't, the frame will twist causing increased fatigue on critical sections of the car (front end, mid section, rear end).
This was the main reason Centennial switched to steel framed cars a few years back because their aluminum framed cars kept breaking on them due to not building a properly strengthened frame. The other issue was they would simply re-weld over cracks that showed up in the frame and not find out why the cracks kept showing up. Those two main causes were the main reason for the switch of materials. I've checked for cracks after a race and the entire time I've only ever found three cracks in the weld. Two were by the steering rack which lead to me adding bracing to the area to prevent the rack from twisting, and the other was on the steering shaft support. I could take the steering out of my car on the support that had a needle bearing pressed into it. The part with the needle bearing had the crack in it which was simply not enough weld for that area.
Other than checking for cracks and having a properly braced frame while building, aluminum is pretty easy to work with for the most part. As Mike said, just watch how much heat you have going into parts and make sure you clean the area with a stainless steel brush before welding. If you have a issue with weld taking, use a propane torch to heat the area up, that way you're not wasting time letting the TIG do all of the work.
Mike, around six years ago before the summer races started up after winning the 2010 series, we did actually weigh the car. With me, ballast, and red or yellow tops we got some numbers. Total weight with me, ballast and reds was around 405 pounds. Total weight with me, ballast and yellows was around 410 pounds. Without the batteries (reds or yellows), ballast and myself in the car; dry weight was around 150 pounds. The frame itself I'd need to look at my notes to find that number since I'd need to weight the wheels, tires, tubes, sprockets (wheel and motor), chain, chain tensioner, meter, seat belt, windshield and the tail cone to determine the frame weight without taking everything out of the car to find out. I know I have the weight of the frame written down.
-- Edited by Zaine Stapleton on Monday 2nd of May 2016 03:22:00 PM
-- Edited by Zaine Stapleton on Monday 2nd of May 2016 03:22:48 PM