Hot Rods Tubing Joinery-Braze or TIG?

I just watched a show called "A Craftsman's Legacy". The show was about building bicycle frames. A man named Steven Bilenky was the builder. They showed him brazing the frame together. When finished the joint was a thing of beauty. The tubes flowed together like they were cast in one piece. The much larger radius of the brass fillet at the joint is what made the whole difference between a TIG welded joint and the brazed joint. I was a certified stick welder and have MIG and TIG in my shop, so I always weld on my hot rods, but IMHO, the brazed joint is a much more desirable joint esthetically. My concern is the strength of the joint. Which is stronger? And by an how much?
Used in a non-structural application, I'm sure it would be good enough. They put those bicycles through some torture.
Just curious. I may have to try some brazing.

 

Are you sure what you saw was brazing and not "silver soldering"? Brazing is a different process. I have done a ton of silver soldering and built alot of production soldering fixtures and jigs over the years and depending on the alloy / mix you use and the quality of the joint (fit) you're soldering, it is incredibly strong. Not only bicycle frames were and are done this way but so were motorcycle frames at one time. My 1929 Harley Davidson frame used the same process albeit with an alloy of solder that was more heavy in brass.

- EM

 

Bird Cage Maseratis were brazed.

 

Harley and others used brazed joints to build their frames. And yes , the front down legs were also brazed to the neck casting. Maybe sweated is a better term? Mopar beat me to it. Lol. Lippy

 

EM, I'd love to see a pic of your Harley. Lippy

 

Couldn't speak to the exact alloy used but they kept saying brass and brazing. It sure made a nice looking joint. I just wonder if it is as strong as a tig joint.

 

Brazing (English Brazing) is very strong, the material acts as a gusset to the joint, and the lower temp . does not create a heat affected zone when thin material is used. The reason its not allowed in racing is that is that people without skill or knowlege would be atempting to braze their chassis together in their garages instead of having it done by a professional

 

Butted and brazed, probably not. But if a tube is inserted into another tube and brazed or (sweated) I would bet as strong or stronger. depending on the material ect... but joint wise at the joint, bet so.

 

Damn, late again. lol

 

this show?



Looks like they might have done some metal finishing, afterwards?

Which process you use, kind of depends on what you're building, and how you're building it.

 

About 50 years ago Cotton Werksman built a space framed ‘27 T that was brazed using 60,000 psi rod. He used plywood to make a frame jig and I think he might have tacked it together first by gas welding before brazing the joints.
It ran a blown 392, set up rear engined and had home brewed front and rear independent suspension.

 

I saw this Crosley powered car at a show, a mini front drive Miller replica. The front suspension was fillet brazed together.

 

Also

 

Yes, this show. They didn't show any metal finishing. The joint looked pretty good untouched. Of course, this guy had been brazing for years. I wouldn't doubt that a little file work was in order.

 

So, Norton welded the production bikes and brazed the racers. Interesting.

 

Yep. I was always told it was because of the early Chromoly tube and the need to heat treat/anneal/normalize after welding. The early aircraft that first started using CoMo tubes were brazed. That followed to bikes. No need to have as heat treat oven large enough to fit a whole frame into.

 

I worked on a '65 Griffth [TVR] Ford 289 HP & 4spd was tube space frame and all tubes, mounting tabs, etc were brazed..Fiber Glass body was dropped on and glassed in place.

 

Done correctly, brazing is plenty strong.

The problem is it is easy to screw up,
by people that don't know what they are doing.

 

I believe what you saw is known as sifbronze welding in the UK
See:
https://www.weldability-sif.com/media/sif_tips/sif_tips_07_bronze_welding_brazing.pdf

 

Brazing, Tig, Mic, stick welding are a dependent on the skill of the man doing the welding and the design of the joint. What I see a lot is very small TIG welds that look beautiful but have no penetration and no fillet strength. I worry about these welds, but they seem to hold.

Bones

 

Yes, Bugatti used that system in many chassis & suspension parts, there were taper pins in there as well. Bob

 

I've seen more dead caterpillar MIG welds than I care to see with near zero penetration. Bob

 

Morris Bresnahan from New Hampshire built front engine dragster chassis back in the 60's. They were a thing of beauty. I never heard of any of the brazing failing.

 

TIG brazing might be a better way. No flux.

 

It would appear that the video posted by Squirrel shows the guy building bicycle frames uses TIG to tack the tubes together.

 

All the XKE Jaguar front frame tubes were furnis braised fron the factory

 

I'd say as some others have that the skill and knowledge of the person doing it has a lot to do with it.

 

The original solar-electric race chassis built to compete in the Tour-de-Sol NE race, by Jim Worden of Solectria used brazed Chr-Mo tubing. High perf. & Lt. wt.

 

Had a buddy that had a ladder bar setup installed in his Ranchero to run at MAR (Wentzville Mo).
He stopped at my shop to have me look at the job, the welds where beautiful but only looked superficial. I said to take it back and have it redone.
The guy that did the work said it was fine, so off to the track he went and proceeded to brake all the welds and role up his drive shaft.