welding the frame

i searched and didnt actually find the question. today im starting to bob my bike. i will be making it a hard tail. i used to be a pretty decent welder with an o/a rig. i dont have access to a mig. do you think i can safely weld a hard tail on using o/a or should i break down and go pay a shop? i know a few guys on here are from oak harbor..... if you have a set up, give a brother a hand?

 

I hard tailed my bike and used a stick rod for all my welds. Sure, MIG or TIG will look prettier, but if you know your way around a welder, then it really shouldn't matter what you use. But I'm curious, I've never heard of an o/a rig. Maybe it's a local thing. What is an o/a rig?

 

oxy aceteline would be my guess

 

yup, i use it to weld exhausts all the time. as far as a frame i'm not sure but then again i can't weld that well so if you're good at it then you'd be the better judge as rather it would hold up or not.

 

I have never welded with an o/a rig but concerning stick and mig, Stick penetrates further. The way I have seen most people on here make hard tails it seems to make a pretty nice triangle that is going to be really strong no matter which way you go about it. If you do a decent job with an o/a rig and you can make a solid weld I would go for it. No school like the old school.

 

The big difference between gas, mig and tig welding is the HAZ (heat affected zone) . Gas welding has a large HAZ, mig is smaller, and tig is smaller yet. This has a big effect on High strength steel (burns the alloys out of it) most of the older bikes have frames made of mild steel thus not much affect from gas welding. The important thing is good penetration and clean welds. Fishmouth all your joints to a good fit.
do some tests with scrap tubing then try to break the welds. Use 1/8 wall D.O.M. or thicker. Oh did I say test your welds!

 

Small jet, nice swirling pool, poke plenty in, good luck.

 

Of course, Oxtacetelene. Wasn't even thinking about that for welding a frame. Don't really know if I would try that. That's pretty good for sheet metal. I'd definitely try some test welds for sure first.

 

thanks for the info.... i think i will be able to weld it safely after a few test beads of course. ill keep you all posted

 

My vote would be to TIG weld. NHRA has rules for roll cages thar have to be TIG welded. I guess If racers depend on that cage to save their lives in case of an accident. I would want that type of weld on my bike to make sure my life was protected while going down the hwy.

Just my 2 bits

MN

 

The NHRA also specifys 1 5/8 o.d.x .118 mild steel tubing, or 1 5/8 x .083 chrome moly tubing for roll cage tubing. Frame tubes on the xj rear section are at best 1 o.d.x .083 regular tubing (not dom) as far as I can tell the frame is mig welded at the factory. I dont see how any advantage would be gained by tig verses mig. If you roll your bike, the last thing you'll be worried about is the frame. Again do some destructive testing so your sure that your welds don't just look good...they are good.

 

Does not make any difference NHRA will not except any mig weld on any roll cage period. Just be carefull thats all I'm saying. We don't like to hear about anyone getting hurt. Make sure those welds are good like M66 says.

MN

 

I'll have to agree with meister66. I don't think road rash really cares if your frame is TIG or MIG or duct taped together. I'm not all that up on NHRA rules, but there is a big difference between being surrounded by your welds and sitting on top of them.
The main thing is, you dont want your bike breaking in half while tooling down the road. Stick or MIG can more than adequately handle that job. I'm a little iffy on the gas welding, tho.

 

Actually per the NHRA rulebook you can MIG or TIG mild steel but you MUST TIG chromoly for a roll bar or cage.

just my.02

 

do you think beating it with a big hammer for a while and putting it in a vice grip then using a big pair of channel locks to bend/break it would be sufficient? what tests would you all advise? and not to be an ass(i know it sounds a little that way) but if my bike could flip over and put over a ton of metal going 150 on my weld........i would let someone else do it.

 

Make a T out of the same tube that you will use for your hardtail section. Fish mouth it weld it. Stick the upright part of the t section in a vise bang on either side with a hammer (teter toter style) till it breaks ( don't hurt yourself) if the pipe breaks before the weld breaks yer good. If the weld breaks try again. make a Y section try to break it like a wishbone from a turkey.

 

will do! thanks for the ideas