Originally Posted by
ksisler
UMan -
I didn't see any mention of making them thicker just for MIG'ing. I guess that could be a reason since they mostly support folks homebrewing lawnchair bikes, trikes, trailers, etc. Their site has some impressive photos of completely projects. /Kerry
Normally the weight of the walls is a function of the tubing that was used (duh) but in the sens that if your source is say SS the wall thickness may be X or if it is 4130, or 1020 something different. Brad at AZ stick welds all his project with a fairly heavy trode.
I guess we could ask Frank/Welder if MIG actually puts more heat into the weld that TIG. He would know. I have both tools, but never compared them...
Technically MIG would be less heat, since to make to perfect runs in either MIG or TIG, the MIG is going to be run faster, not to mention the cold start. However bike welding is difficult, and there are lots of starts and stops, controlling the heat consistently is not what MIG is good at. So you might want more beef to prottect against the spikes.
In Cars the predominace of square sections, and some redundancy you don't get in an HPV, mean MIG is a lot more efficient.
I had always suspected that a TIG provided a stronger joint,
TIG allows independent control of heat and feed. This allows the operator to eliminate the cold start or too hot problems in a run, and to take the time to go just so. Inherently a weld is a weld.
The availability of rod in Chromoly for the TIG is helpful for bike building.
It doesn't hurt that it is available, but it is not the right stuff for welding a bike, you could get by with it. Chromo rod is for structures that will be heat treated, quenched and tempered fully. Very rare process in bike building with 4130.