Hi Noel, Thanks for asking!!! You can mix the powder with a paste
flux and then apply if you do need a paste solder, would be better
to have the right product, but in a pinch this will work.
Yes, you can do the operation of sweat soldering all in one
operation. I do this in preparing a plate for champleve enamel. I
cut out the “top” plate and then cut out the design I want to have
as a part of the enamel. I then make it very flat on the back by
sanding. I use a piece of plexi glass to which a piece of sand
paper has been taped on. The plate is made by making sure the ends
of the sandpaper go all around the piece of plexi so that you have a
sanding surface that is uninterrupted by any tape. You can make this
of any type of sandpaper that fits your project. You may want to
have at lest two grades of sandpaper for this project.
Then you take the piece that is going to be the back plate, and sand
that flat on the area that is going to next to the top. In other
words, the inside surfaces of each plate are to be sanded flat. Now
comes the tricky part.
Place the back plate on the soldering surface. I like charcoal if
it is a small piece. I use fire bricks built up like an oven with
an open top. It can be successfully dine with just two sides also,
just so you have the heat reflect back onto the soldering area for
proper heat. Take the front plate, put paste flux thickly on the
“back” or the side that will be soldered to the other plate. Sift
the powder solder over the flux (use a mask please) and do this over
a piece of paper so that you can recover the powder that goes other
places than the metal. Now, place the front piece over the back
piece in the exact position that you want this to end up. You can
use “T” pins to hold in place if needed. I like using a fire (kiln)
bricks if you are going to do this all at one time and get the back
piece to solder to the front piece all in one operation. You must
make the determination if this is a fairly large piece or it is very
cold out, so that will you have enough heat. If I have any doubt,
then set it up with additional fire bricks acting as if it were a
cave with an open top. Use lots of heat. Do not go in timidly, go
in with determination. In order not to burn out the paste flux, you
have to apply enough heat to let the flux do its thing. Go in with
the heat hot and fast. It may seem like you are going to have a
problem, but we did this exercise at a week long workshop in New
Smyrna Beach this past January and it worked like a charm as long as
you applied enough heat quickly and applied enough heat. If you do
not do this hot enough, you will deplete the oxygen and the flux and
the solder will get black without flowing. When you are applying
heat you will see the flux start to get glassy on the edges and also
the solder get a little bit dark gray. Keep working on this and go
in hot. Do not draw back the torch to see what is happening or go
in gently when starting. It almost seems like it will not work, but
believe me we did lots and lots of samples using this method. If
you are using the traditional sweat soldering technique, then you
melt the solder on the first part (top), and turn it over, apply
flux to the bottom of the top, and then go ahead and use the method
that you are probably familiar with now. Please do not pickle
between the original flow of solder on the “top” as this will
inhibit the flow onto the back sheet (bottom).
If this is not clear, please let me know. Wish I could do this in
pictures. Beth Katz
PS. I do not sell the organic binder as a separate commodity. You
can use the Handy Flux with the powder to make a solder that will
flow, but it will still not have the same properties as the paste
solder already in the syringe. I am adding a new product by special
order, paste solder in a jar containing one ounce. I find it more
convenient for application in a syringe, but others may have a need
for it in a jar. http://www.myuniquesolutions.com