Questions on Roll Cages, Welding, and Ignition

[HotRoddin]

SlowGT is right ... a roll cage is not something you want to learn to weld on.
First to learn to weld properly takes a lot of work and even more practice, and second welding fairly thin walled tubing where the fit isn't always perfect is some of the most difficult welding there is.
Welding is a lot of fun and it can give you a great sense of accomplishment, but start off on a set of lift bars or a driveshaft loop not on a roll cage.
If that car goes dirty side up, you don't want your life depending on a bunch of your practice welds !