All, I have been making some pieces with rather large silver granules
of about 3 mm. Currently I am buying casting grain and sorting out
the best ones. They don’t have to be perfectly round, but they
can’t be saucer shaped or have sharp edges. In a 10 ounce batch of
grain I can get about 2 ounces of usable large granules. I’d like
to make/remake the ones that are too flat or sharp, rounder.
The only thing I have done at this point is to cut rounded holes in
a charcoal block with a round bur and remelt the pieces there. This
has been unsatisfactory because the beads are too oxidized (and
therefore very frosty when pickled, so that they don’t match the
other grains) and it takes far too long.
So, I checked Untracht’s Jewelry Concepts and Technology, but the
granules he shows being made are much smaller than I want to make.
I know that whatever I do they won’t be perfectly round and that’s
OK, in fact it is preferable. I also love the shiney finish the
casting grain comes with, as opposed to the frosty finish I get when
I remelt them with my torch.
Anyone have any experience or opinion as to how I could proceed?
I’m going to try the method in Untracht, but if anyone has any
helpful hints or ideas, let me know. Anything that is especially
oriented toward mass production of these things is even more
helpful. I’d love to be able to make casting grain like the big
metals houses do, but can this be done with a torch or do you need
expensive melters and non-oxygen atmospheres?
Larry, You don’t say whether you’re working with sterling or fine
silver. I’ve found that I can melt fine silver with the torch and
produce MUCH shinier granules than sterling. But in either case,
pickling them then tumbling them can get them nice and shiny.
You can get your 3mm granules by experimenting a bit with jump
rings, which is my starting point whenever I make granules of any
size. Take a bunch of jump rings of the same size, lay them on your
charcoal block, and hit them with your torch just until they ball up.
Let them roll off the charcoal block and into a deep bowl of pickle,
while still VERY hot. The result should be nice, round (or pretty
round) granules of a predictable size. Once you know what gauge and
size of jump ring makes the granule size you want, you can make a
virtually unlimited supply.
Larry, Set up a solderite board at about a 30-45 degree angle in a
bowl of water. Place either your casting grains or pieces of scrap
silver on the board and hit them with the torch. As they ball up
they will roll down the board into the water and quench in ball
form. They will pickle with a satin finish, but I imagine a few
minutes in a tumbler would shine them up nicely.
I also love the shiney finish the casting grain comes
with, as opposed to the frosty finish I get when I remelt them with
my torch.
Hey there Larry, You can get a pretty nice finish right out of the
shotting apparatus if all things are perfect. Most companies that
sell you the shiney grain actually tumble the grain to give it that
uniform appearance. They put the grain in some sort of mass
finishing machine, often a vibratory finisheer (no media) along with
some burnishing soap and tumble it for a few hours. Rinse it well
with DI water so as not to leave trace minerals from your water
source and there you go. You could do the same thing with your
frosty bits.
Do a big melt(say ten or more ounces) and, from a hieght of about
five feet, pour the molten silver through a stainless steel sieve
into iced water. Use a very wide mouthed metal container for the
water - a bucket will be too narrow.
Then it’s sort, remelt, pour, sort, remelt, pour.
Pretty soon you’ll find the right height and speed to make quite
large quantities fairly fast.
Hi Larry, If you want to melt jump rings to make granules here’s a
way to figure the size of jump ring to use.
Calculate the volume of the granule. 4/3 times pi times the
radius of the granule cubed. e.g… 3 mm granule, 3/2= 1.5, 1.5 x 1.5
x 1.5 = 3.375, 3.375 x pi = 10.6, 4/3 x 10.6 = 14.14 cubic mm.
Select the wire to be used to make the jump rings. e.g… 16 ga
(1.29 mm).
Find the length of 16 ga wire that’ll have a volume of 14.14
cubic mm. e.g… pi x radius squared x length = volume. 1.29/2 =
.645, .645 x .645 = .416, .416 x pi =1.307mm. 14.14 /1.307 = 10.82
mm. A length of 16 ga wire 10 82 mm long will have a volume of 14.14
mm.
Find the size jump ring that has a circumference of 10.82 mm.
e.g… 10.82/pi = 3.44 mm. A 16 ga jump ring 3.44 mm in diameter
will have a length of 10.82 mm & a volume of 14.14 cubic mm.
If you get real technical about these calculations the volume will
be off a little, but I doubt anyone will notice unless you’re making
granules for NASA.
The methodology can be used for any size granule & any size wire.