Custom Tube Bumper, questions

To move my previous post into its own thread.

My rear bumper is about a year off from being toast and my front bumper is close to follow. So I figured it’s time to start thinking about fabbing my own. And I’ve got some questions. I’m a mechanical engineering major so designing this in cad wouldn’t be difficult at all for me and I’m wondering if anyone has cad files for stock or custom bumpers? Secondly it’s time for me to buy my own welder, anybody have any recommendations for a good “budget” or beginner gas/gasless MIG welder? TIG just isn’t cost effective due to me being a broke college kid. Lastly, how do you guys bend tubes and what diameter do you use?