Soldering techniques

Jewelry Discussion
1 
This is where i get into trouble. I haven't yet figured a
foolproof way to hold down the two pieces on a charcoal block so
that I end up with a perfect fit around the stone

Hi Dave, I’m sure you’re going to get some great tips, so I’m
going to introduce you to a process that is used by fabricators
for complex assembly jobs. It may be extreme overkill for your
needs, but you will use it from this day on. If you already know
this process, okay, maybe some of the other jewelers here can
benefit from it.

Wax and plaster assembly technique.

This is an extremely brief explanation. I’ll be glad to follow
up for questions.

You will need a few items;

some quick setting dental plaster (any dental supply has it, a
dental lab might give you a few ounces to get you by, it’s
cheap) regular investment works, but sets slowly.

Kerr #1 sheet utility wax. or any other very soft wax that parts
can be pressed into and stay put.
A mixing bowl, paper cups are ideal.
A mixing spatula, popsicle stick work great a small amount of
water

You begin by pressing the pieces the pieces you wish to solder
into the wax in exactly the position you wish them to be in once
soldered. The depth you insert the parts into the wax depends on
how much plaster you want holding the pieces together once the
wax is removed, I typically push them in about halfway. You will
probably want to coat the seams with some wax to keep the
plaster out. Once all the pieces are positioned, you mix up a
small amount of very thick slurry and quickly build it up over
the metal/wax unit. I then turn the wax over and place it on a
flat sheet of wax paper (or anything flat the plaster won’t
stick to) and let it dry for a few minutes.

Pulling the wax off can be tricky, you might try heating the
plaster enough to drip the wax off, off just enough to pull most
of the wax off. The remaining wax will burn away when heated
with the torch. Once the wax is removed, you may need to scrape
some of the plaster to allow the torch flame access to the
parts. You must make sure all the plaster is gone from the
seams. What you have now is any number of pieces presented for
soldering.

If you arranged them carefully, they will be fairly secure and
heat sinked as well, and you can do all your soldering at once.
This technique is very useful for fusing techniques as well.
Because you are working on the underside of the item, and
because the pieces are effectively heat sinked, it is possible
to actually carefully melt the items together, in certain
circumstances. I have used this technique with complicated
platinum fabrications, and otherwise seemingly impossible
soldering jobs.

It’s a standard jewelry fabrication method, and should be in
every bench jewelers collection of techniques.

I’ll be happy to field any questions that result from this
(poorly presented) method. There is much more to it, and I will
gladly get into more advanced techniques in answer to queries.

Jeffrey Everett

2

…Kerr #1 sheet utility wax. or any other very soft wax that
parts can be pressed into and stay put.

I just bought some modeling clay for this same purpose, but
haven’t tried it yet. Was wondering if you had ever tried clay.
Once I’ve tried it, I’ll let you know how it works.

Sharon

3

Hi Jeff,

Doesn’t the plaster crack when you heat it allowing the pieces
to shift?

There are two products which we dental techs use that you might
find helpful. Coe soldering investment sets rather quickly and
will withstand the heat. I use it to solder even palladium
based alloys. The other product is called Duralay. It is a
dental acrylic used to do direct inlay patterns in the mouth.
It is a powder/liquid material that can be made to flow where you
want it (with practice) :slight_smile: . It will absolutely hold the
parts where you want them.

In doing bridgework we always solder from the front, back or
sides in order to protect the thin periphery of the crowns. In
jewelry the pieces could be arranged on some soft wax and
Duralayed together. In a few moments when the acrylic is set,
the wax is stripped away. A little wax is added on the front at
the joints to assure even heating, and the piece is invested in
the Coe investment face down. Don’t use more investment than
you need to hold the piece and to have a 1/2-5/8" base. It will
set in 10 minutes. Place the piece in a 400 degree F oven run
up to 800 -1000 degrees.

At temp the Duralay and wax are completely eliminated. If you
have solder joints in

several places, be sure to change sides. Solder right, then
left(or vice versa) then solder the middle. If for example you
have 5 pieces to solder together the order would be from left to
right- 1,3,5,4,2. I have seen guys go 1,2,3,4,5 and when they
are done, solder shrinkage and uneven heating has moved the
piece.

You may already know about this technique and these products but
then again maybe not. Let me know. In any case good luck.

Regards,

Skip

                                  Skip Meister
                                NRA Endowment and
                                   Instructor
                                @Skip_Meister
                                05/06/9702:04:02
4

Well, I say heck with buying a “soldering” investment, when
you’ve got investment for casting around, use it. I’ve never had
it crack, and the only reason I think it would is if you tried to
solder on it before it was thoroughly dried. In a pinch I have
used regular old plaster (actually, I was just too lazy to go
upstairs and get some investment.) This tech. usually makes
soldering the pieces so easy, it feels like you’re cheating. Tim
gOodWin @tmn8tr

5

Jeff and Dave,

There is a material used by dental technicians called soldering
investment which will work much better for you than plaster.
This material is formulated to take the heat and will expand at
a rate similar to your gold to keep everything in place as you
want it. It will clean up very easily. You should be able to
get it from any dental supply house. I use a soldering
investment from Randsom and Randolph.

I usually melt off the wax used to hold the parts together by
pouring boiling water over the area and let the piece dry a
little before soldering.

Richard

6

I just bought some modeling clay for this same purpose, but
haven’t tried it yet. Was wondering if you had ever tried clay.
Once I’ve tried it, I’ll let you know how it works >>

We use clay (works well) , we also use the soft silicone molding
rubber, it pulls away very clean.

Mark Parkinson

7

Doesn’t the plaster crack when you heat it allowing the pieces to
shift? >>

We have always used the same plaster we use for casting (R&R
Ultravest mixed extra thick). It cracks a little but hasn’t
fallen apart. We have put rebar (sawblades) thru on paricularly
tricky ones to hold together, making sure they don’t touch the
material being soldered. Hey, its worked for me for years.

Mark Parkinson

8

…Kerr #1 sheet utility wax. or any other very soft wax that
parts can be pressed into and stay put.

I just bought some modeling clay for this same purpose, but
haven’t tried it yet. Was wondering if you had ever tried clay.
Once I’ve tried it, I’ll let you know how it works.

Sharon, I normally use modeling clay and it works wonderful. I
did try plaster one time but it would not stand up to the heat-
so I use investment(whick takes forever to set up). Once the
investment sets up, you can remove all of the residual clay with
a steam cleaner and then do your soldering. This technique works
very well for fabricating coctail rings with multiple layers of
settings.

        Ken
9

Mark Where do you get silicone molding rubber? Thanks
Claudia

10

Where do you get silicone molding rubber? Thanks

Gesswein has it. Castaldo makes it. Its that soft squishy
molding rubber that you don’t need to use a mold release spray
on. Its not intended for the plastering of small parts, but
really works great.

Mark Parkinson