revtothelimit - motorbike forum

It's not fusion welding and it's not brazing, can we leave it at that?

mangocrazy wrote: Thu Dec 12, 2024 11:25 am It's not fusion welding and it's not brazing, can we leave it at that?

Or, it's often called a brazed weld but it's not a weld. (Strictly speaking it IS a brazed joint though. ).

We're all agreed, it's not soldered though.

As I understand it (and I'm probably wrong)

Brazing is like soldering, hot liquid metal is used to "glue" two pieces of metal together, the metal being glued will get hot, but doesn't melt
With welding that uses a filler material the pieces of metal get hot enough to melt and fuse with the filler material

Le_Fromage_Grande wrote: Thu Dec 12, 2024 9:45 pm As I understand it (and I'm probably wrong)

Brazing is like soldering, hot liquid metal is used to "glue" two pieces of metal together, the metal being glued will get hot, but doesn't melt
With welding that uses a filler material the pieces of metal get hot enough to melt and fuse with the filler material

I’d go so far as to say brazing is hard soldering.

Le_Fromage_Grande wrote: Thu Dec 12, 2024 9:45 pm As I understand it (and I'm probably wrong)

Brazing is like soldering, hot liquid metal is used to "glue" two pieces of metal together, the metal being glued will get hot, but doesn't melt
With welding that uses a filler material the pieces of metal get hot enough to melt and fuse with the filler material

Brazing is v much like soldering in that the key to the joint is that the joining material wets the surface of the pieces being joined. Hence the use of flux to clean and protect the surface so you get the surface tension to create the capillary action. I did once forget to apply flux to the pipe surface when doing some soldering/home plumbing. Just blobs of solder and no join

I mentioned vacuum rigs earlier. When building them we used to pull the ring of solder out of the Yorkshire couplings (remember when you could do actually do that? ) then reassemble the copper pipework and braze all the joints. (Gas torch + brazing rod on the bench with a big foamed alumina brick underneath the workpiece). So yup, v similar.

(The same surface wetting between the frame and the braze material is needed on those frame joints).

JackyJoll wrote: Thu Dec 12, 2024 9:55 pm I’d go so far as to say brazing is hard soldering.

This is the most accurate description I've seen.

Brazing is what you do when Soldering is too easy, Soldering is what you do when Brazing is too expensive.