My friend and I are building a homemade sidehack we have the bike we just need to make the frame for the sidehack we are wondering what materials we should use and what kind of welder we need?

Answer 1

That depends. Tubing as thin-walled as in nice bikes can't be bought from a regular hardware store, you'd have trouble finding even nice Cr-Mo steel there.

Your best bet for building a decent bike is to buy a tube set specifically intended for bicycle frames from an online vendor.

You might be able to find something half way decent from someone selling tubing for roll cages and one-off race cars - but that would still leave you with the issue of head tube, seat tube, steerer tube and bottom bracket having to be of very specific dimensions if you want to be able to use stock bicycle components in the final assembly.

Pretty much the only way around not having to buy a tube set is to buy another bike, cut it apart and use it as a donor for bottom bracket, head tube and seat tube.

I've built an experimental bike once using conduit pipe for the frame, it's thick enough to be welded with a wire-feed arc welder (forget about stick!) but it's really a poor material and not well suited for a serious bike.

If you go for a tube kit, which I strongly recommend, I'd also recommend you to go for brazing rather than welding. It'll add less thermal stress to the seams and give you a better shot at a good result. Besides, such a frame can be taken apart and corrected if it should end up lopsided.

You have the choice between a lugged frame and a fillet brazed frame. IMO fillet brazing is a bigger testament to builder's skills, while lugs leave more room for artistic decorations. Lugs also helps hold the frame together during fabrication, which can help avoid warping of the frame.

If you really insist on actually welding, then TIG would be my first choice.