Brazed copper joints safe to ......° ?

[Captain Nemesis]

Ive got an old copper hot water cylinder, and Im toying with the idea of upcycling it to a firepit.

No idea of design yet but its going to need legs/supports/frame, and soldered joints arent going to last long...

Does anybody know if brazed joints would withstand the temperatures?

I dont mind buying a decent MAPP torch.

 

[Burnerman]

Think of brazing as a high temperature soldering, therefore you’ll need a brazing spelter which has a lower melting point than the copper - the ‘base or parent’ metal.
A high silver content spelter is probably best and definitely a suitable flux.....brazed joints would withstand the temperatures envisaged.
The copper cylinder is very thin unfortunately so you’ll have to be very careful with the Mapp gas!
You could of course use copper pop rivets which could be easier.
John

 

[catlad]

Its going to melt surely!

 

[EddieM]

Its going to melt surely!

+1 Don't reckon that'll last long at all.

 

[Burnerman]

Normal solder melts around 200 deg and copper at around 1100 deg ( if memory serves) so a silver solder can flow around 700 deg so everything is possible.
I’ve no idea if this project is possible or feasible, of course.....I’m not sure what a fire pit is, and whether the fire directly contacts the copper.
John

 

[EddieM]

Normal solder melts around 200 deg and copper at around 1100 deg ( if memory serves) so a silver solder can flow around 700 deg so everything is possible.
I’ve no idea if this project is possible or feasible, of course.....I’m not sure what a fire pit is, and whether the fire directly contacts the copper.
John

The fire will be in direct contact with the copper. some use charcoal in them

 

[Burnerman]

In which case, the copper is likely to melt
John

 

[Captain Nemesis]

 

[catlad]

That's a pretty little fire!

 

[Captain Nemesis]

The last ones a bit industrial looking, and the first 2 a bit beyond my skill level. Just a bit confused between people saying it will melt and the photos of copper fire pits out there. Done a bit of looking, and wood doesnt burn hot enough to melt copper.

 

[cdbe]

Weigh it in and buy a proper one. The ones you picture probably have much thicker walls than your old cylinder.

I just did my annual scrap clear out and got £85 for a pile of rubbish (old car batteries, bucket of copper and brass, kitchen sink, a few old washing machine and starter motors etc). I think I got over £80 just for my cylinder a few years ago.

Some of those upcycled things look like a fireman's picket line and as for the washing machine drums!!!

 

[Captain Nemesis]

Its not about the money. I could just go and buy one without needing to flog the old cylinder. Did wonder about wall thickness though.

 

[Munroast]

depends what you are burning, typical firewood in a sensible sized fire and I doubt it will melt copper, charcoal or coal maybe, Coke almost certainly.

 

[scbk]

Weigh in the copper, old gas cylinders/car wheels can make good burners

 

[Captain Nemesis]

old gas cylinders ... can make good burners

New ones even better. But not for long.