Frame welding?

Oxy-acetylene, MIG, TIG, or stick (arc). It's a mild steel frame, so no exotic processes required. Use what you have available.

-Jeff Deeney- DoD#0498 NCTR UTMA BRC COHVCO AMA '99 ATK 260LQ-Stink Wheels '94 XR650L-DreamSickle We don't stop riding because we get old, we get old because we stop riding.

No offense, Jeff, but oxy-acetylene is considered brazing, not welding, and is definitely not strong enough for fixing a motorcycle frame. It's fine for fixing tanks and fenders or cutting steel, but not for structural repairs. The other three methods are far more suitable for welding a frame, IMO.

RADRick

Say what?

k> Say what?

He obviously does not know what he's talking about. Oxy-acetylene welding is approved for airplane frames, and with respect to brazing being unsuitable, lots of race cars have been built with brazed (copper nickel) mild steel frames. Whether it is suitable for a specific motorcycle frame or not obviously depends on the alloy and treatment of the frame.

So...according to you (no offense) there is no such thing as oxy-acetylene welding? Just brazing. Boy, I bet THAT will surprise a lot of people.

ryppy wrote:

?????

Steve

Well, I know that I am surprised. Guess you can't weld schedule 40 pipe with OA. Oh, dummy me.

Steve

That's ridiculous. I have used gas-flux brazing to build suspension parts and frame members for vintage Lotus race cars. They seem to hold together pretty well in a wreck.

Ignore the cross-post. Someone is just trying to rekindle a flame war that finally died out in RMD.

I'm glad they cross-posted, as I was unaware of this group.

Speaking of brazing, I've been playing around with some of the aluminum brazing rod with my torch. No flux required. You have to really brush in into the surfaces well to tin the aluminum first.

My question is this: would anyone trust this material to something structural? I've been using it for some non-critical components. What I have in mind is to use it on a luggage rack for my dual sport bike.

Second question: What is the metalurgical content of these rods? They feel very dense, and filing them is much harder than aluminum, so I'm guessing it is pretty high in zinc.

-Jeff Deeney- DoD#0498 NCTR UTMA BRC COHVCO AMA '99 ATK 260LQ-Stink Wheels '94 XR650L-DreamSickle We don't stop riding because we get old, we get old because we stop riding.

Jeff, perhaps, but I'm betting the guy really doesn't know any better.)

I actually have some experience with the aluminum rod you mentioned. I first saw a similar project at amateur radio "hamfests" where there was typically a wizard using it to "weld" all sorts of unlikely aluminum opjects to each other. e.g. drinp cans, etc. It was pretty lame stuff in the hands of anyone besides the wizard.

I didn't bite until a couple of years ago when my son managed to nearly destroy a storm window frame with a bad basketball throw. With meticulous cleaning, the product worked surprisingly well (got it at Northern Tools) and the repair survived re-assembly and has lasted through a couple of winters.

I even tried the trick of soldering to a drink can, and when I tried to pry off the resulting puddle, it tore the can before I could pry off the material. So, this stuff has improved, but I still wouldn't trust it for anything structural. The specs that came with mine were unimpressive as to strength.

gmc

Jeff Deeney wrote:

Although brazing is no longer road legal in the UK (according to a literalist reading of the MOT Tester's Handbook). A worthy change a few years ago was intended to outlaw poor quality brazed repairs to sheet steel monocoques, but it appears to have caught superleggera brazed tube construction as well - if you _have_ an old Lotus, Aston Martin or Maserati, then you have to go somewhere with A Clue to get it inspected. But then you probably would anyway.

Thanks for the input. I'm thinking that with proper joint design (load things in shear, rather than tension), it may be adequate. So far everything I've built with the aluminum braze has a large area of overlap at the joint, where I've thoroughly tinned the lap surfaces before brazing.

-Jeff Deeney- DoD#0498 NCTR UTMA BRC COHVCO AMA '99 ATK 260LQ-Stink Wheels '94 XR650L-DreamSickle We don't stop riding because we get old, we get old because we stop riding.

Oxy-Acetylene is a suitable welding process for welding steel tubing. I'm not current on airframe regulations but at one time oxy was an approved process for 4130-N tube up to .049 wall. Many aircraft, race car frames and motorcycles have been welded by the oxy process. In the hands of a skilled operator aluminum can be oxy welded. I've observed large cast iron engine blocks being commercially repaired using an oxy-acetylene method in a huge gas fired kiln. Although oxy-acetylene welding has fallen out of favor it is by no means an inferior process.

Superior processes push them out of favor. The question isn't whether O-A is a serviceable process, but whether it is the best/most practical process of the available choices. It isn't. And certainly not worth considering for a beginning welder. Now how about letting this thread die already?

RADRick

Oxy-Acetylene is a suitable welding process for welding steel tubing. I'm not current on airframe regulations but at one time oxy was an approved process for 4130-N tube up to .049 wall. Many aircraft, race car frames and motorcycles have been welded by the oxy process. In the hands of a skilled operator aluminum can be oxy welded. I've observed large cast iron engine blocks being commercially repaired using an oxy-acetylene method in a huge gas fired kiln. Although oxy-acetylene welding has fallen out of favor it is by no means an inferior process.

Depends on your tubing. Some tubing (particularly for bikes) is heat treated during manufacture. You can take this to an O-A brazing heat for fabrication, but welding it destroys the heat treatment. In this case, brazing may actually be stronger.