i use 3/16" brake tubing and a small tank of Oxy and acyetelene (you can get it all at lowes,make sure to pick up something that will also shield your eyes; shade 5 minimum) and get a couple O/A brazing rods and just expierment. I have and built a tube chassis for my friends clod. Just remember your prep though before you weld. Dremel or air grind all welding areas down,notch tubinf for tight fit and chip all slag off. This is a fairly involved procedure. I give it IIII out of IIIII on the hardness scale. If you can weld though this is a fun and asy little project that looks trick and is cheap!