I went to school for welding back in the early 80's They made us practice running beads on 1/4 inch plate. It was kind of a drag to weld on nothing but that. It ended up being close to 2" thick when they said it was time to start on thinner metal. Get some 1/8 bed frame or what ever to practice. change your speed and heat to see how it goes. The J/Y is a good place to get stuff but check behind some body shops to get some free stuff. Ask the owner first, Some folks don't want anyone digging around in their junk. The scrappers usually get all the junk before you get there.