Depends on wether your building a sanction cage or a cage for your own comfort. Im not sure the specs or if they are different as ive only had cages for stock cars, but if it a drag cage or a road race cage or a drift cage, they might each have different minimum tubing requirements as far as wall thickness goes. If your throwing in a cage, for any reason, my first concern would be to ensure its safe. not just home depot fence pipe. Ill get you more info on the available thickness and what sanctions require what. Ill also hunt down weights for wall thickness and material.