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Practical Silver Granulation


#1

Dear colleagues, does anyone have practical and
experience in making silver granulation work ? I know the principles
and have a lot of theoretical but former experiments
failed. Straight to the point help would be very appreciated.

Thanks,
Patrick Storme.
@Patrick_Storme


#2

Patrick, give us some specifics about what didn’t work at what
point. Did you have problems with the base melting before the
granules fused? Did the granules start losing their shape (slumping)?
What gauge base did you use? What patterns did you use (triangular,
diamond with lots of densely packed granules, or flower, single line
with lots of open space)? Give us some place to start!

One thing that helps when doing silver on silver is to remember that
fusing temps are very close to melting temps (20 degrees F.), so when
I see things start happening, I’m ready with a breath of air to puff
on the piece to cool things quickly (tip from the great granulation
guru, Jean Stark). It’s easier to go back in with a torch a couple of
times than it is to start from scratch.


#3

Patrick, Use solder cutting pliers with a hole in the side for
cutting wire solder to 1/16" (Rio Grande #111-607). Cut 28-gauge
(or 30-g or 26-g) fine silver wire, four at a time, into 1/16"
lengths. Spread about 50 wires on a soldering board and use a small
flame to ball the wire. Stay under 1-mm size granules. 28-gauge
of 1/16" wire give you a granule of 0.65-mm (30-gauge will produce
0.3-mm).

Use a lentil-size amount of copper carbonate powder (from pottery
glaze supplier or from finely ground malachite), mixed with 10 drops
of distilled water, 2 drops of glue and 10 drops of Battern’s flux.
Make sure this is a thin liquid because a thick liquid will keep the
granules apart and not let them “solder” to other granules or wire.
For glue, use Klyr-Fire (www.ThompsonEnamel.com) or gum tragacanth
(http://studioproducts.cybrhost.com/store). For gum tragacanth, mix
1/2-teaspoon gum T. with 1/2 cup distilled water, bring to boil,
cool and store in airtight container. (Can also use rabbit skin
glue or gelatin but these products turn to a gel when cool and turn
moldy in a day or two.)

Mix frequently to keep the copper carbonate from settling.

At least slightly dome a super-clean 24-gauge fine silver disc.
Doming prevents the silver from distorting. For greater stability,
start with a fine silver wire design (put in place with glue mixture
and fired with the granules) and bank the first row of granules
against the wire. Also start with a design where granules touch
other granules so the connection is with the disc, other granules
and wire.

If using a kiln, paint the underside of the dome with a thin coating
of yellow ochre to stabilize this surface, but for torch firing,
this coating is not needed.

To torch fire (propane-air pencil torch), place the piece on a
charcoal block in a rotating pan. Slowly heat the piece until the
glue burns off and the metal becomes pink-red. Focus the torch on
the granules until you see a quick liquid “flash” much like when
solder flows.

Air-cool and poke at each granule with tweezers to make sure of the
connection. Aim for a perfect “solder” the first time, but if a
ball falls off, coat a new ball with the copper-glue mixture, reheat
the piece and torch that granule (only that granule will “flash”).
If the same granule falls off again, use scribe or pin to scratch
away the dome surface back down to the fine silver. (This surface
may not accept another try because it has become a copper-silver
alloy.) Do not pickle. If some areas are discolored put the piece
back on the soldering board and bring it up to a pink heat to burn
off excess copper carbonate.

Under 30X magnification, you should see a tiny connection of silver
between touching granules and the silver behind the granules looks
like sterling silver.

To polish the tops of the granules, gently rub with 4,000 or
8.000-grit polishing paper. If you are feeling lucky, gently use a
radial bristle disc across the tops of the granules and next to
them. Do not use an ultrasonic cleaner as it will dislodge the
granules. Also, I avoid using pickle, even after conventional
soldering for links, etc. because the pickle seems to weaken the
granulation. For example, even after a soaking in baking soda, I
had some solidly connected granules crumble off a week or two later.

I have some silver granulation on my web site under “Earrings”. I
did wear a pair of granulated earrings for a month, day and night,
just to see if they would “wear well” and none of the granules came
off.

There are many ways to do silver granulation. This is what works
for me so far, but nothing works perfectly every time, so I am
anxious to hear what others are doing.

Nancy
www.psi-design.com


#4

We tried fine and 950 silver with different coppersalt solutions,
but the grains would never fuse without the complete piece being
melted. The aim of the workpiece is to cover triangular flat surfaces
with beads around 0,5 mm diameter, but also larger beads stacked to
form small piramids. My question is primarely if it is best to use
either fine silver, or an alloy and secondly, which would be the
most appropriate mixture to bond and melt the granules together. It
is possible, as Katherine suggests, that our view on the melting
process was not accurate enough. Nevertheless, if we know we are
working with the right alloy and bonding mixture, we can more easily
concentrate on the fusing moment. Thanks, Patrick.


#5
    We tried fine and 950 silver with different coppersalt
solutions, but the grains would never fuse without the complete
piece being melted. 

Fine silver has a higher melting point than an alloy. Stick with
fine, and you’ll have fewer problems with slumping. Silver on silver
granulation is the most difficult because of the small temperature
difference between fusing and meltdown, and once you are master of
that, you are master of all granulation with few caveats. Prepolish
the base, because it will be difficult to polish out scratches
afterwards without flatspotting the granules.

    The aim of the workpiece is to cover triangular flat surfaces
with beads around 0,5 mm diameter, but also larger beads stacked
to form small piramids. 

I’ve never tried doing a pyramid, so I can’t advise you on this
part.

    secondly, which would be the most appropriate mixture to bond
and melt the granules together. 

The bonding mixture I use is 2 drops hide glue, 4 drops Battern’s,
and 10 drops distilled water (ratio 1:2:5). This mixture only has a
life span of about 6 hours before it starts breaking down. For silver
on silver, I do not coat the granules with any copper salts, nor do I
use any copper salts in the glue mixture. The reason is, although it
does lower the fusing temperature, it alloys with the surface, and
makes successive fusing difficult, if not impossible, without
slumping the granules. Make sure you dry the glue by sitting it on a
warm surface until the glue turns black. This prevents the glue from
"working" and bubbling, and disturbing your pattern. I turn up a
corner of the base piece to facilitate picking the assemblage and
moving it.

A small trinket kiln will make it easier to bring the piece up to
fusing heat across the piece, and a quick blast with the torch tip
from the top makes it fuse together. If you don’t have a trinket
kiln, use a reflective surface, like clean fire brick, and preheat
the surface around the piece first, so the heat will radiate to the
underside of the base, then work on the top. When you see the
"flash", BLOW! When I granulate, I switch to a Prestolite or a
propane torch (yeah, like the ones you get in the hardware store for
$10), because it seems to do better being bathed in a large flame
than a small flame from my Li’l Torch. The exception is when I’m
doing a scattering of granules across a surface, and in that case, I
like the pinpoint accuracy of the Li’l Torch.

Your ideal granulation has a small bond at the bottom of each
granule attaching it to the base, and to the side of each granule
where they touch one another. Your granulation should withstand
pickle, brass brushing and ultrasonic without any granules falling
off. If they do fall off, your fusing isn’t complete.

When doing a grouping, or using a mixture of small and large
granules, concentrate your heat in the densest area first. In a
triangular grouping, that will in the center of the triangle. If it
is a triangle where you have the larger granules at the base and the
smaller granules at the apex, then your flame will be concentrated
more at the base.

Another thing that helps you to be successful is to use a base sheet
that is relatively thin. I rarely use anything heavier than 22 ga.
Your granulated assemblage can be sweat soldered to a heavier piece.
The reason is, that especially for intricate and dense granulation,
your base, if too thick, can retain and radiate more heat than what
can be dissipated from that puff of your breath, and you have
slumping or meltdown. If you only have a few scatterings of granules,
say across a reticulated surface, then thickness of the base is not
as much of a problem, because the granules will not trap heat as a
densely packed area will.

You might find it beneficial to practice with some scraps and just
making some simple patterns that will be no big loss if you have a
meltdown. If you’re successful, then you have little components for
the earring posts to be attached to, or decorative components for
another piece. 98% of your time in granulation is making the granules
and making the patterns. 1% is spent fusing, and 1% is spent
polishing, soldering on additional components and adding the stones.

Nancy covered many other important points in her posting, and
perhaps between the two of us you’ll find the perfect solution.


#6

Patrick, Fine silver is better for granulation than sterling, because
it has a higher melting point.

Janet


#7

About the use of copper salts for fusing/granulation: One Internet
article said that the copper bond will get stronger with each
heating. That would allow you to build your pyramid shapes by fusing
each layer separately. But I don’t know if the is
correct (and can’t remember who wrote it).

I hadn’t needed copper salts for fusing, as long as I used a
tabletop kiln and a torch with a small, soft flame.

That torch recently broke* and I can’t dial down the new torch
enough to avoid overheating the entire piece, so I’ve gone back to
using copper salts. It’s easy enough to make a copper solution, but
I happened to have antiquing solution
(http://www.modernoptions.com/SFpages/PGangel.html) and it works
fine.

Janet

*It was a $10 Bernzomatic microtorch–a poor-quality tool that soon
developed problems. In one way it was the perfect torch for fusing:
The nozzle gunked up until it could only produce a short, round
flame. But it also leaked and after a few months wouldn’t work at
all, so I don’t recommend it.