Brass welding?

[Shiro]

Chaps a wee bit of advice please.

I have to join some brass rod together to make a Torc (a kind of Celtic necklace). The rod needs to be bent into a circle, the open ends joined together and then the whole thing twisted together to form a rod with a closed loop at either end before being bent into the final half circle shape of the necklace.

I need advice on the best way to join the ends of the original circle together that will be strong enough that they will not separate as the circle is twisted.

Hope I've explained it clearly enough

This is what it needs to look like in the end.

 

[gordon stephenson]

I would certainly go for silver solder.

 

[TechnicAl]

make sure the rod is in a softened condition, it will be a lot easier than if its as drawn. I agree with Gordon, solder it

 

[pedrobedro]

I don't think brass welds because of the zinc content so you may only have the option of soldering it.

 

[Hitch]

Looks a bit delicate to be welding, silver soldering probably an easier option for small parts.

 

[PTvor]

Silver solder I'd say as well. It's what jewellers use. I'm not sure about the grade. You don't want any nasties in it, like cadmium. There must be jewellery websites where they discuss the right stuff and where to get it.

I doubt soft solder would be strong enough anyway, but you wouldn't want anything with a lead content for jewellery.

 

[Shiro]

Right then silver solder it is.....
Now has anyone got any links to an idiots guide to silver soldering, and a cheap torch set-up. I only have a couple to do and don't want to spend a fortune on equipment.

Thanks for the info so far btw

 

[Sean]

mapp gas gets hot enough for silver solder - melt the solder with the workpiece not the flame of the torch as you may get cold or dry joints

look for "bernzomatic" as its a cheaper torch than the re badged "Rothenburger"
Yellow disposables of mapp easily found in diy sheds etc

Oxy mapp would be ideal

 

[mike os]

I would suspect the join is in the twist ... not in the eyes, a nice tight but or splice will be invisible to all but the closest of inspections

 

[Shiro]

Thanks Sean I'll have a look.

Mike, yes, the join will be hidden as much as possible in the twisted section rather than left exposed on one of the eyes, I'm hoping that it will be almost invisible when finished.

 

[PTvor]

http://www.cupalloys.co.uk/silver-soldering-tips-c25.html

talks about silver soldering and fluxes here.

http://www.cupalloys.co.uk/fluxes-c59.html

These people do sticks of silver solder in small quantities for about a fiver.

It doesn't sound like a lot for the money, but if you do it properly, you need almost none.

http://www.cooksongold.com/Solders/-Alloy=Silver_Solder/-Type=0/&prdsearch=y

There are certainly others.

As for heat, for a small object you might be able to get away with the gas hob or try with an ordinary gas torch used for plumbing. As others have said, you can get gas cartridges for brazing with a higher flame temperature.

The person I knew who did a lot of silver soldering was a jeweller and she used oxy-acetylene, but she was doing a lot of it.

 

[PTvor]

I have to join some brass rod together to make a Torc (a kind of Celtic necklace). The rod needs to be bent into a circle, the open ends joined together and then the whole thing twisted together to form a rod with a closed loop at either end before being bent into the final half circle shape of the necklace.

If this is a Celtic necklace - it conjures up pictures of Stonehenge and Druids, 1500BC - how did they manage it? Not with gas torches and silver solder.

Or did they make theirs from gold?

 

[chunkolini]

I have welded brass bar using O/A gear, It is similar to brazing but becomes fusion welding because the filler is the same as the parent metal.
Question. Where does the joint go?
Somewhere in the middle is my guess. Do you make up a (cant think of a name for the shape) an endless flattened oval with a small loop at either end then twist it up with a bar through each loop before making it into a loop.
Interested in this one.

 

[Shiro]

PTvor, many many thanks for the links, I'll have a read through tomorrow.

Yes, originally they would have been gold or bronze and the more elaborate ones would have had separately cast ends with half a dozen or more strands twisted together as the ring. If you Google Torc you'll find many different styles.

Cheers again guys....

 

[Shiro]

I have welded brass bar using O/A gear, It is similar to brazing but becomes fusion welding because the filler is the same as the parent metal.
Question. Where does the joint go?
Somewhere in the middle is my guess. Do you make up a (cant think of a name for the shape) an endless flattened oval with a small loop at either end then twist it up with a bar through each loop before making it into a loop.
Interested in this one.

That's it exactly! with luck you will never see the join. Sadly I have no O/A gear

 

[chriskelland]

Hi Shiro,

Have a look at this site.

http://www.cupalloys.co.uk/popular-silver-solders-leads-to-prices-c26.html

Chris.

 

[Tiggy_dorset]

Don't mean to hijack the thread, but just one quick question : I have never used the flux coated silver solder, are they any good? less or more difficult to use than solder with the powder flux? Does it hurt to use them with the powder flux if one felt the need to use powder?

Ok sorry, it was 3 questions

 

[Shiro]

Thanks Chris, I'll have a mooch!

Tiggy, good questions I could do with knowing too ;-)