If you stick to about 15mm mild steel tube you can get excellent results from a hole in a bit of 3x3 hard wood, flared slightly on the face. Tube goes in hole, bend a tiny bit, move out of wood a bit, bend again, etc. I did the body frame for this 1927 Chevy Stovebolt Special this way.
And yes that is masking tape holding all the joints together, waiting for the welder to do his magic.
Cheers,
Martin