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Sweat soldering Bi-Metal


#1
I use the lowest heat possible and Easy silver solder but I have
problems keeping the Bi-metal from "cupping" as it heats. 

This is just a guess, as I’ve not actually used this stuff. But the
problem, as I’m sure you know, is that the two layers expand at
different rates from heating. It occurs to me that if you’re using
too easy a grade of solder, you may not be getting the metal hot
enough to reach annealing temps. Try heating it a little hotter, to
be sure it’s fully annealed at the point where the solder is to flow.
I don’t know if this will work, but perhaps it will help, since this
way, at least, you know the metal is soft, and able to redistribute
and eliminate stresses in the metal which are forcing out of flat.
What I don’t know is whether it will at this point relax again and
flatten out for you. It will, after all, at temperature still have
expanded differently on one side than the other. But it might,
nevertheless, work. Worth a try, I think.

Peter


#2

I have used bi-metal quite a bit and have had the same problem as
you are having. Especially when trying to solder rings and
bracelets. My solution was to put stainless steel binding wire on
the piece to hold it together and then solder. Works well for me.
I do not have a problem using bi-metal to do other things eg.
making beads,earrings,pendants etc. I love using it and also solder
it to silver and vice-versa. Louise


#3

Grace, some of you problem maybe in the way the metal you are using
is made. The layers are not bounded in the traditional Mokume-gane
techniques. They are not welded together but hot rolled under high
pressure. Perhaps you should try Shinning Wave Metals original
Bi-metal that is fusion bonded. I have never heard of our material
doing anything like you describe. Bill


#4

Hi Grace, I can relate some recent experience of sweat soldering. It
is not with bi-metal but I hope will be helpful. I have made quite a
few designs recently that use layered pieces of sheet, some of them
using pattern sheet (with photo etched patterns, quite thin and easy
to overheat). I had recurring problems at first of the metal cupping
as you describe or just getting what looked like a bubble in the top
layer. Extremely frustrating as there was already a lot of work
invested in the piece at this stage. And once you get a bubble,
especially in the pattern sheet, there is no going back. It is
deformed. So I had to go back to basic soldering steps. The problems
arose when I tried to rush or skip basic steps. The kind of thing
that makes you kick yourself. Success came when I made sure both
pieces of sheet were flattened and then properly annealed before
beginning. This helped avoid any flexing of the sheet when heated
during soldering. Then I pickled the sheets and got them super clean.
Fluxed well and applied small bits of solder generously and evenly
distributed. Then heated and brought both pieces of sheet up to
temperature. I haven’t had a problem since. The bi-metal may behave
differently and you may already be following all these basic steps.
But if not, try them. The annealing beforehand really helps. It seems
like alot of steps but is so worth it when the two pieces of sheet
solder together flat. You don’t have to sit there heating and
heating, fighting against the metal and risking a meltdown. Hope this
is of some help. -Carrie in Tennessee