Soldering silver to penknife

I’d like to create a pen knife with silver side plates, but have been
told that the heat required to weld the silver to the base metal will
un-temper the knive’s spring, which allows the blades to open and
shut firmly. Any suggestions?

Is silver strong enough to function as the knife’s side plates? It
doesn’t have to be “strong” like a cold chisel, but merely strong
enough to keep the rivet holes from widening and getting mushy under
normal use. Normal use would be using the knife to open a letter or
clean under a fingernail. If this solution is viable, then would I
make the rivets from silver wire?

How would you hide the rivet heads so they wouldn’t muck up the
symmetry of the outer silver plate?

Thank you for your help. This Orchid exchange is really fascinating.

Rick Hyer
@rickhyer

Rick, I have such a pin knife, also known as a fruit knife, that was
made in the late 1800’s by an American silversmith. It consists of
side plates made of steel with a steel spring and silver blade. Silver
side plates are then riveted to the steel plates. Also has a very nice
design engraved into the spring. Hope this helps.
Frank Goss.

Rick,

I’ve done several hundred of these knives. We soldered them - and
riveted them, depending on the size & requirements of the client.
Usually they were small - 3" or less stainless steel penknives. We
also overlaid a lot of stainless letter openers with sterling silver
panels.

One caveat - all of these knives and letter openers had perfectly
flat side panels…

To solder them, I would take a 6" x 6" or 6" x 12" piece of 24 or 26
ga sheet silver, and clean the side to be soldered with a 3M pad &
alcohol.

We use “Stay Brite” silver bearing solder, which is a low temp solder

  • 400 degrees. It comes in various sizes of wire on spools. We use
    1/16". The manufacturer listed on the box is: J. W. Harris Co., Inc.,
    10930 Deerfield Rd., Cincinnati, Ohio 45242. It is available in
    hardware stores, gunsmith suppliers, and some jewelry suppliers carry
    it.

Warm up the sheet, and using the flux sold by the same company, melt
the solder. About 3/8" piece of wire solder for every square inch.
Spread the solder to “flush” the entire sheet with a 1" steel, brass,
or copper spatula. I usually grab whatever sheet metal scrap happens
to be lying about the shop. You can use a painters spatula, which has
a handle to protect your hand a bit from the heat.

Sometimes it is necessary to “flush” the knife panels too…

Then, clean the knives - in both the ultrasonic and the steamer - and
dip them or brush them with the flux. Find some level fire brick to
lay your sterling sheet on. Put as many (or few) of the clean, fluxed
knives on top of the sheet as you wish. We would try to get about an
eighth or quarter inch space between 'em, so as to be able to saw
them out afterwards.You can use an oven, or a “rosebud” torch to
bring them and the sheet up to the solder melting temp.

If you use the torch - you can see what is is happening - and add a
bit of solder, or slide them around to make sure that they are
"wetted" with solder evenly. Let cool, clean the flux residue off in
boiling water/ultrasonic, dry, and saw them out of the sheet. Leave a
little bit to file/sand off later, unless you are really good with a
saw…

This solder bonds well to any metal - steel, stainless steel, brass,
and even aluminum. (though it requires a different flux, and I
haven’t tried it, the manufacturer claims it will work…)

Repeat the operation on the opposite side of the knives…

When we riveted them, which wasn’t often - we used a bit heavier
gauge of sheet - up to 18 ga. if the job looked like it needed it. We
would knock out the rivets that come in the knife, and make a jig for
the drill press vise to accomodate individual sterling blanks, cut to
the approximate dimensions of the knife panels.

After the holes are drilled in the sterling, we would either replace
the rivets with some of the same/similar material used on the
original, or use a contrasting colored metal - ie. hard brass. You
can decorate the rivet heads, or just set them and file 'em off
flush.

Do not forget to chamfer the holes - before you set the rivet! I use
a bud burr or conical burr to just bevel the inside of the hole edge
a bit.

We have a belt/disc sander with 220 paper, set up in a box to catch
the “dust” from sanding - and we use this to trim up to the original
knife panels. Then “detail sand” the plates you’ve put on, and polish
as usual.

We hand engraved most of our production, which made it easy to
incorporate the rivets into the design. They became the centers of
the flowers…

By the way the correct term for these side plates/panels on knives
and letter openers is “scales”…

There are other solders (Brownells’ Hi-Force 44 comes to mind) and
other methods or variations on these methods that will work.

Hope this helps, if I left out some detail, or didn’t make it clear
enough, let me know.

Brian P. Marshall
Stockton Jewelry Arts School
704 W. Swain Rd.
Stockton, CA, USA 95207
209-477-6731 Office/Fax
209-477-6535 Workshops/Classrooms

Rich, I did this a few year ago on my pocket knife. First, I drilled
out the rivets and took the knife apart. Then I soldered the silver
plates to the metal plates of the knife. When I put the knife back
together I used solid silver rivets and bezel set round blue
sapphires on the ends of the rivets. It looked very nice, only two
problems. The silver made it heavy, at 5 ounces for a 3 1/2" long
pocket knife and it need to be polished all the time as it turned
black.

Hope this helps,

Jimmy Eriksson
J. Eriksson Gallery
Scottsdale, Arizona