Are you building 1:24 or 1:25 scale frame? I you are, my suggest is that use anything but lead. I built frame from brasstube to '63 Impala and it was 2,5mm thick. Oh yes and 2,5 mm is about one inch! But measure and make a good drawing and if you think about soldering with liquid gas, be very careful and unburned plates are helping very much. If you don't have them, do the soldering work on a big stone far away anything what can burn. I can say just good luck, it's not easy but my Impala frame was my first brassframe ever and I think, it's quite good. Impala frame