I would recommend that you take a course at the local welding supply store. This will be much cheaper and you get to try out the latest and greatest equipment. I think that you will find that TIG welding is the best as it can be used on any metal. Gas welding is not suitable for bikes due to the concentrated heat fatigue. Don't get me wrong, you can certily join 2 pieces of steel together with gas welding it is not the best method. TIG is clean and almost artistic if done correctly. You local supplier will even rent you a welder so you can play at home. I rented a TIG to build a swim platform for $110 per week. This would have been credited back if I purchased a TIG welder. I don't know if you have HAUN or Airgas in your area. Check it out.
chevy57