Once we were happy with the ends we welded them solid and ground down all the welds. Grinders and flap discs can make a crappy-looking weld more presentable. Not everyone is a born master welder, but you’ll get there with practice, and practice comes from building stuff like bumpers out of pipe. Don’t learn welding by building a rollcage, as that is safety equipment that could one day save your life. And don’t build a rollcage with pipe; only tubing should be used for cages and other safety equipment.