Welding a tall bike.
 

Sorry about the question. I'm sure it's been answered before but there only seems to be 5 threads in this forum.

I've recently decided to try my hand at frankensteining some bikes and I'm wondering what the best way to attach all this stuff together. I have access to an oxy-acytelene welder but should I be looking into mig or tig welders? Is there a noticeable difference in strength? I'll likely be using bikes with gas bike frames and I don't know if heat treating is a concern or even if I should worry about it.

Thanks.

brazing with oxy/acetylene is a really good way to do things like this. If you were good at torch welding, that is ok, but I find it much harder than brazing. Tig could be considered ideal, but it's expensive and can have problems if the original bike was brazed.

You have the default forum settings, you can show more threads by increasing the interval to show posts. Search will go back years, as the zombie thread problem demonstrates so well

You will definitely want to check out some of the work being done at the Freakbike Nation forums.

http://www.forum.freakbikenation.com/phpBB3/index.php

No need, a gas torch will do just fine--on steel. You may need to get a smaller heating tip, which only costs $15 or so.

Aluminum can be torch-welded but it presents particular difficulties, no matter which kind of welder you have. (this is the reason there are far more custom-frame builders working in steel than aluminum)
I assume you mean "bikes with gas pipe frames"? For casual-use stuff lots of people do use muffler pipe, electrical conduit or whatever. It is heavier than usual, and not very stiff tho'.

If you want to build something nice and permanent, it's not much more money to buy the good tube, which is 4130 steel. There's places online to get it but look around for local metals supply places first, as they are probably cheaper. Get .049" wall for kids bikes, or .065" wall for adult-sized bikes if you don't know which to pick. The next-thickness-up is .080", which would make a very strong but rather heavy frame.

Steel doesn't need to be heat-treated after welding; it re-hardens in a few days to nearly what it was before (-aluminum does require re-heat-treating, which is why I said to avoid it-).

Also fillet-braze it with brass rod, don't weld. Welding thin steel causes a lot of metal on the back side to burn off. Brazing is at a much lower temperature and won't burn the steel at all.

My question to you would be...do you know how to use the equipment... the wire feed welders are easier to learn, in my opinion... That is if you do not know much about welding. good luck, whatever you decide.