I weave precious metal wire and sheet by hand. The process of weaving creates "fabric". I shape that "fabric" into ribbons and ruffles, spirals and loops, which become earrings, brooches, necklaces and pendants.

As a child, I wove potholders from knitted loops and made baskets from reeds.  As a student, I wove with copper, aluminum, titanium, niobium, and, on special occasions, silver. I launched Barbara Berk Designs with woven sterling silver, and later added high karat gold. Now, I'm weaving with the ultimate precious material: platinum.

Weaving is the interlacing of two sets of elements, one vertical and one horizontal. In my first collection, the vertical element - the warp - is sheet that's been cut into strips or wedges. The horizontal element - the weft - is multiple strands of thin wire twisted together. The pattern is a Plain Weave, in which the wire crosses over the sheet, then under the sheet, continuing over one warp, under one warp. Four strands of thin wire are twisted together, creating a thicker weft, which is more malleable than a single wire of the same diameter. As the twisted wire weft crosses under the sheet, the sheet is pressed down over it, which "locks" the weft in place, and adds strength to the piece.

In my second collection, both elements are single strands of wire: a thin wire weft and a thicker wire for the warp. The pattern is called Soumak. The thicker warp wire of 18kt gold, provides strength; the thinner weft wire of 22kt gold, provides the malleability needed to do the tight wrapping that creates a dense weave. The warp is the skeleton, the weft is the skin; the two alloys in combination create a structurally sound piece.

The metal work hardens in the process of weaving and again in the process of shaping. My weaving, therefore requires metal that is soft enough to manipulate with fingers to create the "fabric", but that will work harden sufficiently to hold its shape when complete. I knew platinum is much stronger and heavier than gold; that its high working temperatures and ease of contamination require separate, and in some cases, special tools and equipment. I knew that platinum was different from any metal with which I'd worked.

I decided to start with the Soumak.  Though it is the more complex pattern, I could complete, shape and test a small piece in less time and with less metal than with the Plain Weave.

THE SEARCH
My search started in earnest in the Spring of 1996. There was lots of buzz about a new alloy, a spring platinum, that would be soft if it was heated and quenched, and "hard as nails" if it was heated and air cooled. In talking to a large supplier, I was told that this spring platinum would be too hard, but that 95% plati num/ 5% ruthenium should work. The first samples arrived with the temper "as drawn" - they were much too hard to weave The supplier could not define "as drawn". He could not tell me how the wires had been made, nor how hard they were. But he was willing to anneal both wires to dead soft. I did weave and shape a clasp with the annealed wires, but the piece was a dull, drab gray.  Because of its curls and folds, the Ribbon Clasp can't be polished with wheels and compounds: I had successfully woven platinum, but I had a product that wouldn't sell. I could get no response, no answers from the supplier about the cause of the dull finish nor how to prevent or eliminate it.

The following Spring, I asked Jurgen Maerz, Director of Technical Education for the Platinum Guild International, USA, about my search for the proper alloy and the newly identified issue of surface finish. Jurgen told me about new magnetic tumblers with tiny stainless steel needles that could get into the nooks and crannies of my weavings and polish the platinum. He also introduced me to Greg Normandeau at Imperial Smelting and Refining. Greg ran a number of samples from which we learned that even a .002" hard draw produced a wire that was too hard to weave. 

Early in 1998, Jurgen introduced me to Jolanda Hoekstra of Engelhard-Clal, who suggested I talk to Dick Lanam, Director, Product Development. At a meeting at the New Jersey plant, I put my gold weavings on the table and told him that I wanted to be able to do the pieces in platinum. After discussing my handweaving process and the results of my search to date, Dick suggested he measure the tensile strength of my 18kt and 22kt gold wires to enable us to select an appropriate platinum alloy. This was the breakthrough I needed! The selection was now easy.

A combination of the platinum/ruthenium warp with a platinum/iridium weft worked very well. I found that platinum Soumak takes longer to weave: it literally takes more time to move the wire weft around the warp. But it's easier to shape than gold; the platinum is more resilient, more forgiving.

The next step, at Jurgen's suggestion, was to send the clasp to Elaine Corwin at Gesswein to determine the tumbling process. Though I had successfully woven and shaped a piece of Soumak, the wire was still a dull, lifeless gray. Elaine put the clasp into a magnetic tumbler. The piece sparkled, and the impingement problem was minimal.
I was so encouraged by my success weaving and finishing the platinum Soumak, that I decided to test the Plain Weave pattern.

Unlike the gold Soumak, which requires no finishing, the gold Plain Weave requires smoothing the edges where the sheet curls around the first and last rows of wire. This smoothing is accomplished with coarse rods, Shofu cones and the occasional use of a burnisher. I expected to have edge work, in fact more edge work, on the platinum brooch. What I did not expect was the roughness of the woven surface itself. It was sharp, almost prickly, where the sheet warp passes over the twisted wire weft underneath. Again, Elaine Corwin had the answer: she put the brooch in a rotary tumbler with steel shot.  It came out not only with a smooth surface and edges, but it was brightly polished! It sparkled!

The next step was to find wire suitable for the stickpin. As the attachment mechanism for the brooch, it requires strong, hard wire. Torry Hoover of Hoover and Strong suggested I test the harder of the two alloys developed by Steven Kretchmer: the PLAT/S+™2 works very well for my stickpins.

I knew when I started this journey, that platinum was different from any with which I'd worked. What I discovered along the way is that I could take advantage of that difference to create wonderful jewelry.

To those of you who haven't yet taken the plunge, I encourage you to do so: the metal is different, the product is fabulous and there are many resources to tap for information and assistance.

V8N8

A Platinum Tapestry:
Weaving all the Elements Together
Barbara M. Berk
Barbara Berk Designs

This is an abbreviated version of the original work. For full technical details, please consult the original paper.