Brazing queries

[C08]

A couple of queries
Can you braze brass to bronze?
Can you braze using a gas plumbing torch?
Is silver solder much less stong than braze?

 

[paulajayne]

Yes
Yes
and yes.

Use Sif bronze as a flux

 

[mainsail1]

Quite tricky though. My attempts have been pretty poor.

 

[PilotWolf]

I learned at school in metalwork class - probably considered to dangerous now.

I could arc weld OKish. But when I went back to the UK a couple of years ago my welder was on the shelf in Dads garage collecting dust - I knew had used it fair regularly for hobby things as retired.

Well turns out at about 70 years old he’d gone to college and taken classes.

He had a very nice TIG and MIG set up now!

W.

 

[earlybird]

Brazing involves melting brass or bonze material, so brazing a brass/ bronze parent metal is likely to cause damage.
Typical brazing temperature can be over 900 deg. C. Oxy-propane is really needed for this sort of temperature for anything other than a very small workpiece. A butane torch; no chance.
Silver soldering at about 650 deg. C is a much easier diy proposition, and not much weaker than braze. An ordinary propane torch, with separate gas-bottle, will suffice but a fair amount of heat is still needed. I often use a burner of several kilowatts, ie over 1" in diameter, with fire-brick insulation around the workpiece.

 

[rotrax]

Brazing is like grown up soldering, done on a brazing hearth using soft heat to get both pieces to be joined to the correct tempreture where capilary action draws the brass into the joint, which is often pinned or loosely riveted so is held in the correct place. A borax flux is used.

If joining metal without machined joints low tempreture bronze welding can be used. A borax flux or flux coated rods are commonly used, but I prefered the Calor gasfluxer which used a methanol/borax liquid flux through which the acetylene bubbled and burned with a green tinge to the flame. My old racing sponsor Bill developed it and sold it to Calor.

Brazing and bronze welding are completely different techniques.

I have often bronze welded brass to bronze and vice versa, but with Oxy Acetylene kit. A propane/butane torch would not have the control for bronze welding, but would be fine for brazing on a hearth. Propane/ butane and Oxygen might, but I have no experience of that except for flame cutting.

Substantial bits, no problem, thin sheet stuff silver solder might serve better.

 

[Catalina36]

Brazing is like grown up soldering, done on a brazing hearth using soft heat to get both pieces to be joined to the correct tempreture where capilary action draws the brass into the joint, which is often pinned or loosely riveted so is held in the correct place. A borax flux is used.

If joining metal without machined joints low tempreture bronze welding can be used. A borax flux or flux coated rods are commonly used, but I prefered the Calor gasfluxer which used a methanol/borax liquid flux through which the acetylene bubbled and burned with a green tinge to the flame. My old racing sponsor Bill developed it and sold it to Calor.

Brazing and bronze welding are completely different techniques.

I have often bronze welded brass to bronze and vice versa, but with Oxy Acetylene kit. A propane/butane torch would not have the control for bronze welding, but would be fine for brazing on a hearth. Propane/ butane and Oxygen might, but I have no experience of that except for flame cutting.

Substantial bits, no problem, thin sheet stuff silver solder might serve better.

A revelation thanks, I've never heard of bronze welding before. Could it be done with a heat source other than oxy-acetylene? IIRC acetylene cylinders require special permits and insurance.

 

[TernVI]

A couple of queries
Can you braze brass to bronze?
Can you braze using a gas plumbing torch?
Is silver solder much less stong than braze?

What do you want to fix?
When you start asking for 'strong' in the same sentence as 'brass', it's a recipe for people to rush off at tangents.
What are we talking about?
How is it going to be used?

 

[Graham376]

Could it be done with a heat source other than oxy-acetylene? IIRC acetylene cylinders require special permits and insurance.

It's a couple of years since I got rid of my Oxy Acet gear but certainly no permit or insurance required then for domestic use. They can be hired from most hire shops but maybe cheaper to pay someone else to do the job.

 

[Catalina36]

It's a couple of years since I got rid of my Oxy Acet gear but certainly no permit or insurance required then for domestic use. They can be hired from most hire shops but maybe cheaper to pay someone else to do the job.

Interesting thanks. I was going from what my now -retired welder told me, that he had issues with the insurers when he had acetylene cylinders in his workshop and some talk of an exc;lusion zone in the event of a fire.

 

[HissyFit]

Interesting thanks. I was going from what my now -retired welder told me, that he had issues with the insurers when he had acetylene cylinders in his workshop and some talk of an exc;lusion zone in the event of a fire.

That would be for insuring his premises/public liability, not for the actual using of the acetylene.

 

[Graham376]

That would be for insuring his premises/public liability, not for the actual using of the acetylene.

Yes, fire regs and insurance can be very strict for commercial premises but, welding gasses never appeared on any of my home policy's questions or excluded risks so, I never declared the bottles.

 

[RivalRedwing]

acetylene regs are pretty strict these days in commercial premises, with good reason - frisky blighters in a fire and aferwards:
Safe use of Acetylene - Fire and explosion

 

[Catalina36]

acetylene regs are pretty strict these days in commercial premises, with good reason - frisky blighters in a fire and aferwards:
Safe use of Acetylene - Fire and explosion

Dodgy stuff. Brings me back to the original question, can bronze welding be done with anything other then oxy/acet or does eg propane not get hot enough?

 

[Graham376]

Dodgy stuff. Brings me back to the original question, can bronze welding be done with anything other then oxy/acet or does eg propane not get hot enough?

Depending on material, brazing can be done with something like a Bullfinch and propane but the flame area is much bigger and not as hot as a welding nozzle.

 

[TernVI]

TIG?

 

[Catalina36]

TIG?

Interesting. I have a TIG set though I'm as much use with it as a cow with a musket. I thought the point of bronze welding was that it's a bit like soldering, ie the base metal doesn't melt or fuse whereas with TIG it would surely?

 

[TernVI]

Interesting. I have a TIG set though I'm as much use with it as a cow with a musket. I thought the point of bronze welding was that it's a bit like soldering, ie the base metal doesn't melt or fuse whereas with TIG it would surely?

I think that rather depends on WTF we're trying to mend.
I am not a welding expert but I thought that the difference between Bronze Welding and Brazing was that in Bronze welding, the workpiece is dissolved somewhat at the join to alloy with the filler, rather than a clear boundary between parent metal and brass filler in Brazing?
I see no reason why the weldpool in TIG can't be mostly filler?
I have seen TIG used on copper in this way.
TBH I know more about soldering and gold compression welding than I do about TIG, so I'm happy to be educated.

Other people seem to think that 'Bronze welding' is a brazing job that gets through the MoT....

 

[escapism]

My old Arc welding set came with a carbon arc torch for brazing, which was used with flux coated brazing rods. I've not used it for years, but remember it as crude, unwieldy, but effective. Lots of YouTube demos available.

 

[TernVI]

My old Arc welding set came with a carbon arc torch for brazing, which was used with flux coated brazing rods. I've not used it for years, but remember it as crude, unwieldy, but effective. Lots of YouTube demos available.

My Dad had one of those, wondering what happened to it now....
I remember it as being crude and unwieldy.
In Dad's hands, not so sure it was effective except as some kind of substitute for fireworks.
YMMV!
Might it work better with a modern inverter welder than a buzzbox from Exchange and Mart?

Seems you can bronze weld with a MIG set too.