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Silver solder pasta or sheet's


#1

Hi to all,

I wonder if anyone make their own solder paste or sheet’s for
silver. How? Can you give me some recipes or ratio mixing. I read
Peter Rowe article

http://users.lmi.net/drewid/PWR_Silversolders.html

but I need to know the mixing process.

Thank you
Balsanu Gabi


#2
I wonder if anyone make their own solder paste or sheet's for
silver. How? Can you give me some recipes or ratio mixing. I read
Peter Rowe article 
http://users.lmi.net/drewid/PWR_Silversolders.html 
but I need to know the mixing process. 

The main problem you’d have in mixing up your own solders is that
zinc is quite volatile, and trying to mix it directly with molten
silver and copper will tend to vaporize a small portion of the zinc
before it can fully alloy. Whether this would mess up your solder
enough to matter, isn’t clear to me. Personally, I don’t think
commercial silver solder is costly enough to warrant going to the
trouble to mix up my own, but your circumstances may differ.

I’d suggest finding a supplier of a high zinc brass alloy. It would
need to be lead free, so as to be only copper and zinc. You’d then
calculate how much of this alloy to add to your silver in order to
add the required amount of zinc to your batch. Additional copper
could be added just as copper (I usually use scrap electrical wire as
a source of copper when alloying. Seems like I’ve usually got some
around, and it’s quite pure).

The usual method for alloying is to put the required metals in a
crucible and melt em together. If one is much lower melting than
others, like the brass, you might either melt the silver and copper
together first, and then drop in the brass, or put the brass on the
bottom of the crucible under the silver and copper. Putting the
silver on top of the copper in the crucible will help to reduce
oxidation of the copper during melting.

For the most part, though, don’t be too scared of this. You’ll
likely get decently usable results no matter how you go about mixing
it up. If you can’t get a suitable brass to use as an alloying
addition, and need to do it with actual zinc, try rolling some very
thin silver sheet to almost a foil. Use that to wrap up the zinc into
a small packet. Melt the rest of the silver and copper together, and
drop that packet into the melt, pushing it under the surface with a
stirring rod so it’s not exposed to the air any longer than needed.
The packet will simultaniously melt, and as it does so, along with
alloying with the silver, will also be dropping the temperature of
the
melt, hopefully reducing any volatilization of the zinc to a
tolerable level. If you’re using a melting furnace rather than a
torch, then you can probably simply put the zinc on the bottom of the
crucible, with the copper and silver above it. As the zinc melts, it
will alloy itself with the copper and silver pretty automatically.
Stir the melt before you pour your ingot of solder.

Hope that helps.
Peter