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Silver solder

PostPosted: Tue Apr 15, 2014 1:21 pm
by Tim Rolls
OK, so I have a set of bellows with the leather all sewn on, (is that how you spell sewn? looks odd.) and I need to do some metalwork. I know it is possible to make bellows without, but the pattern I'm following for my first set uses metal, and I'm using it as a learning process.
This seems as good a price as any for a small quantity of 1.6mm sheet.
http://www.ebay.co.uk/itm/Brass-sheet-1 ... 19ea588a6c

All the advice is to use silver solder, but it's not that simple is it, naturally. Even if you go for the lowest melting point solder for ease, you find that not everyone classifies things in the same way. As a starting point, would this fit the bill?
http://www.ebay.co.uk/itm/SILVER-BRAZIN ... 27e0d010ef

Any advice welcome.

Re: Silver solder

PostPosted: Tue Apr 15, 2014 9:30 pm
by Richard Evans
The two Ebay links look good. Nice to get a 'kit'. I have always found this job a complete pain which is why we have been using a wooden block with a removable tube for many years.
For the soldering, get a good joint surface (flat so no gaps), apply flux carefully so that it is continuous around the whole joint. Use plenty of heat and don't apply the solder before the joint is hot enough. It woiuld pay to practice on some small pieces first. Done correctly, the solder will flash around the joint by capillary action but you will still need to apply the solder in several places around the joint. A classic problem would be not getting the section under the tube- the acute angle- hot enough. I use ordinary disposable propane cylinders and for this I would use the largest torch head I have. A proper brazing torch would be better.
Cleaning it all up is another pain because you can't get a wheel into the angle. You can use tiny wheels in the Dremel but they tend to leave streaks.

Others will know better than me as far as silver soldering goes but as I say, when we wanted a regular supply of bellows, I actually dumped the whole design. The other thing about the block/removable tube is that the bellows lie flat in the case.

Cheers
Richard

Re: Silver solder

PostPosted: Wed Apr 16, 2014 10:40 pm
by pipemakermike
Make sure that the joint is clean, and what Richard says is correct but dont overheat as this will also cause problems. If you are using the standard silversolder stick ( about 1.6mm diameter) it can be helpful to bash it flat on the end as this will help to limit the amount of solder applied. You don't need much to make a good joint just a little fillet. When I was an apprentice we used to clean off the flux, which will be glass hard when cool, by boiling it in a solution of alum (I can't remember the full title of this stuff but I will update this if it comes to me)

Re: Silver solder

PostPosted: Tue Apr 29, 2014 10:02 am
by Tim Rolls
Thanks Richard and Mike. Lost my hard drive so getting back into things just now, events have got in the way, but hope to get my fingers burned really soon now.

Re: Silver solder

PostPosted: Tue Oct 21, 2014 2:54 pm
by Silversmith
I imagine that this post is no longer active but here's my input: I am not a lover of working with brass but the principles of using silver solder also works to a point with brass except I find that brass has a tendency to oxidise more readily than silver during soldering. There are different grades of silver solder, Hard & easy are the most common since they conform to assay standards hard has a higher melting point than easy. There is also a harder grade again called enamelling silver solder" & finally the softest is easyflo solder, which doesn't actually meet assay standards. The basic principle is to start any multiple soldering work using the highest melting point solder & work down through the grades so as not to melt the previous joint. The other point is that higher melting point solders require higher melting point fluxes I personally always use a "Tenacity 4 or 5" flux which will actually suffice for all grades. In practice a silversmith should be able to repair an antique article safely in the knowledge that the correct order of solders would have been used, so the body joint will not melt apart when trying to get the handle off a teapot instance. I feel sure however that there must be brazing solders available that would be cheaper & match the colour of brass better. All of the silver solders & fluxes are available at "Cooksons Gold".

Re: Silver solder

PostPosted: Wed Nov 26, 2014 5:23 pm
by Tim Rolls
Thanks, belatedly, for that technical stuff. All information gratefully received.