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An unconventional approach to granulation


#1

Hello all,

This note is written primarily for a newbie such as myself. If you
have not already tried creating a piece with granules fused to a base
coat you might want to try. My approach was a bit unorthodox but still
worked. Why granulation? Because the technique is so old. For me its
the idea of sharing a tradition that is very ancient.

see: http://www.cais-soas.com/CAIS/Art/granulation.htm

Two years ago I new a little about the history and process of
granulation and was able to see it demonstrated by a lady in the
Creative Jewellers Guild of British Columbia. I saw her create the
granules in fine silver and fusing them onto a fine silver surface.
Even though I was familiar with one theory of the process I did not
have the confidence to try it myself.

But by yesterday I just had to try it. My approach to the project
was governed by Charles Lewton-Brain’s comments in his paper “Forming
Using Metal characteristics: Fold-Forming (p 4) in which he discusses
the distinction between Process (”…what happens when one affects
the metal.") and Procedure ("…a way of effecting process).

In general, I followed the procedure as outlined by Cogswell (1). I
tried using his “free fall method” of heating the paillons on an
inclined charcoal block and had only modest success. The granules
often became stuck in the charcoal. However I made a sufficient
number to complete the project.

For a base I used a 5/8" square of 24 guage sterling. I scribed four
lines into its surface (McCreight[2]) to help locate the granules.
After scribing I cleaned the sterling with a brass scratch brush and
detergent. For the source of carbon I used hairspray (Finesse,
regular) diluted with isopropanol. Once the granules were arranged I
librally (most likely too librally) sprinkled copper carbonate
(CuCO3) over the surface and let it dry. I made both Cu(OH)2 and
CuCO3 from pickle used to remove the firescale from copper. My
source of heat was a small cylinder of MAP gas fitted with a
Bernzomatic JTH-7 nozzle with its holes plugged. It created bushy
corona of gas. I stopped soon after (but probably not soon enough) I
saw the beads “sweat”.

The piece turned out pretty much like what Cogswell describes. I
liked the textured surface of the sterling. I suspect that it would
make an interesting surface for enamelling.

The whole process reminded me of doing a “lab” in high school
chemistry or physics. It took under two hours. As for the piece, my
teacher gave me a B; some granules were missing, others weren’t
perfectly spherical, and the design was not very imaginative. But it’s
a start. It also shows to go yah that there’s more than one way to
cook an egg.

David

(1) Cogswell, John (1992) in Metals Technic pp 3-13. Ed by Tim
McCreight, Brynmorgen Press, Cape Elizabeth, Maine, USA. 151 pp

(2) McCreight, Tim (1991) The Complete Metalsmith p32. Davis
Publication, Inc. Worcester, Mass. 192pp