Granulation granules

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Jan 12, 2011, 10:04:00 PM1/12/11
Can anyone tell me where I could buy presorted granulation granules
here in the states?


Peter W. Rowe

Jan 16, 2011, 9:17:54 PM1/16/11

The main company that made these for jewelers (they actually make/made them for
electronics and industry, but sold also to jewelers, as a very small side line
for their business, was SPM company in New York. They were bought by a company
called Coining Inc. The coining inc. web site still lists high quality spheres
(granules) as one of their products, available in many different
alloys. Most of the alloys listed on their web site are industrial, rather than
jewelry, but they do list both pure silver and pure gold granules. I imagine
they also do, or could, produce various gold karat alloys too, though I don't
know prices or availability or minimums. When it was SPM there was a setup
charge of something lke 300 dollars (don't remember if this was per ounce or per
order) in addition to the metal cost, which makes these not even close to being
cheap or economical, especially in silver. Given the current cost of gold, if
that's what they'd charge over the gold cost, then it wouldn't be all that bad
in terms of a percentage over the metal... I assume that Coining Inc also has
similar price structure to the old original SPM company, but don't know.

The only other source I know of (though undoubtably there are other industrial
companies producing such a product for industry) is Rio Grande, the well known
tools and findings supplier. They carry argentium silver granules in a variety
of grain sizes. Again, not cheap. An ounce is 300 dollars in their catalog. Or
3 gram lots (which is still a lot of grains) for 40 dollars.

That cost is why many, if not most, jewelers doing granulation make their own.
It's not really all that hard to do. Draw your desired metal into fine wire.
The finer the better, but dependent on the size grain you wish. Wind the wire
onto a suitable small mandrel and cut apart like any other jump ring making
process (I use the very thin .006" thick seperating disks, which produce a cut
about the same thickness as an 8/0 saw blade. Cutting a coil of small rings
off a mandrel with these disks is quick and easy. When you do this, the amount
of metal in each jump ring will be identical, so the resulting grains will be
the same size. The size of the mandrel you wind the coil on, and the size of
the wire you use, determines the size of the grains.

Make or otherwise inprovise or find a small iron/steel box. Put a layer of
powdered charcoal in the box, then sprinkle a layer of the jump rings as dense
as you can but without any touching. Cover with another layer of charcoal
powder. Repeat till the box is full. Cover and fire in a kiln to fuse the
rings into grains. The time and temp depends on your alloy, and the size of the
box. Sounds complex, but it's really not that bad once you've got it worked
out. For small amounts, spread the rings on a new smooth charcoal soldering
block, set up at an angle over a dish of water. Melt with a torch, starting at
the bottom of the slope. As the rings melt, they roll off into the water. Quick
and easy if you don't need a large number of grains.

Peter Rowe

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