GTAW Chromoly bike frame....any advice, FILLER? TRICKS?

[zank]

I just ordered a tube set of double butted chromoly tubes for a bike I'm going to build. I have heard that 309L is ok, but some say use 70s6. Any bike builder out there with tricks or ideas that have made thin wall CrMo welding turn out nice? Thanks

If it's just Nova's 4130, I'd use ER70S-2 or S-6.

[zank]

Try this for a neat way to make the fishmouth joints with a paper template.

http://metalgeek.com/static/cope_custom.pcgi

I built my first 50 or so frames with this approach.

[youngnstudly]

I was just excited to see a person who wasn't a frame manufacture produce a top quality frame. I could certainly see doing destructive testing in your case (not only with the issue of liability, but product testing that could potentially increase sales). I was just surprised by Jody doing it after showing all the work of getting all the parts tacked and fitted just right before welding it together.

It did give him good reasoning to make the video though, which showcased a new filler rod and compared it to a more commonly used filler rod (for those of us not in the industry), plus it allowed the viewers to see how much easier and accurate the fixture table makes production. And as you mentioned, you got an honorable mention and credit for your participation and help.

So when are you going to produce a video of you producing your welds? They're absolute perfection!

[Johnson]

Thanks for the info Zank. I'll let everyone know how it goes. I'll try the spindle sander approch on a test tube and if it fails to work I'll switch to the paper tempate. Should be fun....and a LOT of work

[Rambozo]

It may not be as pretty but that seems the route to take. Paper and die grinder that is. I just never thought of that. I have a few used endmills I can strap to a drill that'll work too. Things are really coming together now. In my mind that is.

I've yet to watch Jody tig the tubing but I'm wondering if it could be done with stick if you're careful enough. Maybe grind down a bit afterwards then glass and paint to cover. It wouldn't look near as nice but would function just as well I'm sure.

I almost forgot about this guy. AFAIK he welds up all his bikes with a stick welder, and copes his tubes with angle grinder and file. Maybe not quite what you had in mind, but interesting.

http://www.atomiczombie.com/

[Tanh]

Recumbent trikes! That's amazing and exactly up my alley. The fact that he stick welds it all is just gravy. Thanks for the site. I have a lot of reading to do.

Right now, I'm wonder about the particulars of his process. Materials, settings etc...