Bimetal product I'd like to see

While we are on the subject of bimetal products. I could use
sterling silver sheet that has a thin layer of silver solder on one
side. This way a design could be cut out of the bimetal sheet that
could be sweat soldered to a backing sheet of sterling silver as an
applique. This would be a lot easier than melting a layer of silver
solder on the back of the applique sheet before sweat soldering. It
might make joining layers of preformed sheets easier also.

Does anyone know if such a product exist and where one might purchase
it in modest quantities?

Thank you.
David Luck
Iowa City

That’s a good idea, but of course you must already know that you can
make your own! Just flow solder to the sheet silver BEFORE cutting out
the design.

Solder is an expensive way to go! Just use fine silver!

    I could use sterling silver sheet that has a thin layer of
silver solder on one side. 
Does anyone know if such a product exist and where one might purchase
it in modest quantities?

Some suppliers, like IJS and RGA used to sell such a sheet under the
name of “solder-flushed sheet”, but no longer carry it. Perhaps some
other supplier still carries it.

Another way to accomplish having just a thin layer of solder is to
use powdered solder. Make a slug of solder large enough to hold onto
easily, or use sheet solder. Scrape the solder across the slug or
sheet until you have a small pile of powder. I do this onto a paper
plate because it’s easy to fold into a funnel. You have to use a file
rather than sandpaper or cutting disks. The reason why is you can’t
remove the contaminants from the powder. After you have a pile of
solder powder, take a very strong magnet and draw it through the
powder thoroughly. This will remove any metal filings which will
contaminate your solder.

Next dip the piece you want to sweat into flux, preferably a thinned
out paste or liquid type. Let the excess run off, and dip the piece
into the powdered solder. Tap the piece gently against an edge, and
the excess will fall off. Place it onto your metal you want to sweat
it to, and heat, preferably from underneath. It will suck down like
magic, perfectly and with no leftover residue.

I kick myself everytime I try to sweat solder something without doing
this, because I will either have too much, not enough, or air pockets.
Powdering the solder is worth the extra trouble. K.P. in WY

I still have trouble with lumps in the flowed solder on the one side.
I thought that a manufactured product might be easier to work with
and save a step or two.

This is interesting. Do you think that silver solder paste would
give the same results without all the solder filing? I have never tried it
myself.

   This is interesting.  Do you think that silver solder paste
would give the same results without all the solder filing? 

I know powdered solder is used for filigree to avoid this problem.
Because there is more surface area in contact with the heat source, it
flows more readily without damage to delicate parts. Some people like
to use it exclusively because it’s easy to use for difficult
applications. Others wouldn’t use it if you paid them.

Mostly it has to do with the expense (or elbow grease) of powdering
the solder. Some suppliers do carry powder solder, but you pay a
premium price for it. On the plus side, you don’t use as much as you
do with either wire or sheet, because it’s only as much as needed to
flood a joint. With wire and sheet, you use an excess to draw it along
the seam to flood it, and then you have cleanup. With powdered solder,
any excess can be wiped off with a wet brush easily before the heat is
introduced, saving clean up time. You will have to weigh whether it
will be easier to get to the joint to do cleanup with traditional
solder, or if it will be better in terms of time/expense to go with
powdered solder.

Paste solders usually have cadmium or flourides added to the mix to
further lower the melting temperature. They should only be used with
positive ventilation because they present a health hazard. You can
make your own paste solder with powdered solder mixed with a flux of
your choice. You can even put it in a syringe. But it dries out
quickly, and adding water to DIY paste solder after it’s already on
the joint just makes a mess and causes the solder to thin out too much
at the joint, resulting in not enough solder.

It’s worth experimenting with. You’ll soon figure out where it pays
you to use powdered solder, and where it’s better to go with
traditional solder. K.P. in WY