I want to make a sphere in silver but doming blocks aren’t
really half of a sphere and making two domes and a straight
walled piece to connect them really isn’t a true sphere. Any
ideas here? Dave
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Hi Dave, If you make two domes in your dapping block, you can
make a good sphere. The dapping block can be a bit shallow. Keep
doming up the two discs until each is exactly half. Measuring
with calipers, the diameter of each half must equal twice its
height. Start out with discs one third larger than the desired
diameter of the finished sphere. When doming them, try to avoid
hitting the center as much as possible. Work around the sides so
that the middle doesn’t get too thin. After soldering, allow the
ball to cool slowly, don’t quench it in pickle. If you did it
right, it will probably float :).
Have fun Tom Arnold
Hi Dave Stephens, It doesn’t matter if your doming die does not
have perfectly hemispherical depressions. It’s all in the way you
work the doming punch over the silver while it’s in the doming
block.
Without doing a drawing it’s a little hard to explain, but here
goes. As you work the doming punch backwards and forwards and
around the growing concavity of the hemisphere, the silver thins
and the metal “creeps” and expands, but is constrained by the
concave shape of the doming die.
I often demonstrate this to my students, purposely letting the
silver “creep” around the circumference of the doming punch as I
hammer and work the surface. You can expand it to a stage where
you can’t pull it off the doming punch.
Making a hemisphere isn’t simply a process of banging a piece of
circular silver plate straight down into the nearest hole of the
doming die. One has to gently work the interior concave surface
with the doming punch, forming it to the specific curve you have
chosen. You can easily see if your forming is happening correctly
by the shinier surface where the convex side of the silver
hemisphere has connected with the steel concave of the doming
die.
I hope I’ve explained this clearly. I’m sure other Orchidists
will add their own cogent descriptions of the process. It’s very
satisfying to make a near perfect sphere - but drill a tiny hole
to vent internal pressure during any afterwards soldering. Hope
this helps. Kind regards
Rex from Oz
Hello Dave:
What size silver bead do you want to make? You will find hollow
sterling beads available thru RioGrande as well as many other
sources for far less than you can make them yourself.
Reguards;
Steve
Hi Dave.
It seems to me that you have a couple of options. One would be
to solder the strip on the inside in a gauge of metal far thicker
than you need, and solder it so it sticks up from the joint. You
can file it away to fit the contours of the domes and voila. I’ve
never tried this, but it’s always seemed to be a reasonable
method.
Another thing you could do would be to slightly dome the strip
you’re going to solder in with a pair of forming pliers or a
plastic mallet and a forming stake. It might take some
experimentation, but it might work. Please realize I have no
practical experience with this, these are just ideas thrown out
into the ether, which may or may not stick. Good luck. 
-KieranI want to make a sphere in silver but doming blocks aren’t
really half of a sphere and making two domes and a straight
walled piece to connect them really isn’t a true sphere. Any
ideas here? Dave
I use dapping dies and punches. I assume that they are the same
as “doming blocks”. My suggestion is thet you need to continue
dapping the discs into smaller depressions until the half sphere
is complete. This may seem counterintuitive, but your disk does
not have to model itself to the shape of the die. It just needs
to become a hemisphere. If you punch long enough you will find
that the hemisphere will continue to wrap itself around the
punch, making it nearly impossible to remove from the die.
HTH
Bruce D. Holmgrain
Maryland’s first JA Certified Master Bench Jeweler
@Bruce_Holmgrain
http://www.goldwerx.nu
1-703-627-8580
Dave,
The dapping block doesn’t need to be a full half-sphere. The
compensation is in the dapping punches which, on the spherical
end, are much more than a half- sphere. By maneuvering the metal
around in the depression you can create more than a half-sphere.
Actually it’s possible to capture your punch within your dome as
you close the edge diameter.
I smooth and polish the top edge of the depressions in my block.
This eliminates much of the marring of the metal that occurs as
a larger piece of metal is drawn into a smaller depression.
Smoothing the edge of the depression makes the depression even
less of a complete half-sphere, but that doesn’t matter unless
you are trying to use the block and punch in a single strike
fashion to create a half-sphere.
Dick
dave you need one form die to make a couple of halves although
the edges would have to be cut back to the center line using a
small lathe with a fixture.in the end youll end up with two
halves evenlycut and right on size.
Cache
Hi, Dave: I recently made a rattle which was a sphere. I used
the hydraulic press. If you’ve used one you probably know its
pretty time consuming. You need to make a die and anneal your
work frequently. When you make each half you leave a flange
which is used to solder the two halves together. I’ll be glad to
give you more detail if you want to do this. Frances
Visit me or “beam me up” at:
http://www.toast.net/~frangro/index.html
Speaking of spherical forms in jewelry, I have a collection of
old silver jewelry from Yemen and one of its distinguishing
characteristics is granulation. Some of the granulation consists
of row upon row of tiny spheres. How did they do that?
Ann
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Dick
What was your method and tools used to smooth the edges? I have
often thought it should be done but wasn’t just sure how to go
about it without harming the bock.
some of the granulation consists ofrow upon row of tiny spheres. How did they do that?
Question: Were the tiny spheres solid or hollow? If hollow, I’ll
join you in asking the question “how did they do that?”