Whether a person is a full-time designer or craftsman, or even more so if a person is an occasional designer or bench person, it is vital to know the basic forms of semi-fabricated product that are generally available and how to best use them in completing a jewelry project. 

In a production facility, essentially all basic forms begin on rollers that are extremely smooth, highly polished and kept exceptionally clean to ensure a bright, as-rolled finish on the sheet and to preclude any contamination during the rolling process.  Since this sheet form is often only an interim form, the ultimate finish is usually achieved nearer the end of the manufacturing cycle. Depending on the final dimensions desired, the metal may need to be annealed at least once to achieve a particular dimension and hardness.  A very thin sheet, called foil, is produced by many successive passes between rollers.  A very thin strip, sometimes called ribbon, has many applications within the jewelry industry.  If your project has special requirements, specify them at the time of an order with drop shot, also called Grain.  Drop shot is produced by melting platinum sponge, which is like a powder, with an alloying metal in a computer-controlled induction melting device, and then pouring the molten metal in a controlled manner into water.  When the molten metal enters the water it quickly hardens into grains of irregular size and shape. In this case, where the entire output of a 400 troy ounces melt is being remelted to produce the sheet, the irregularity of size and shape is inconsequential.  However, if this alloyed grain were to be used for general casting purposes, it would most likely be screened or sieved to classify it by size. Very small grains sometimes cause problems for casters who melt using a torch, in that they might fly from the crucible when the pressure of the flame hits the metal.

Sheet
In order to create sheet, or plate as it is sometimes called, drop shot is melted and cast into an ingot.  This ingot is then run through a breakdown mill, a series of rollers that reduce the shot.  The ingot is then run through a finishing mill, once again a series of rollers, in successive passes to reduce it to its desired thickness and width.  Specify the surface when placing your order.  Dimensions, tolerances, hardness (if known, in Vickers scale) and finish should be specified if important.  A realistic delivery schedule should also be agreed upon.

Wire
Wire is usually round or square, but other shapes may be produced with special dies.  Once again, to produce wire, drop shot is melted and is cast into a wire bar.  This casting is either forged with a drop hammer or extruded into a bar.  An extruder is a massive device that propels metal with great force and considerable speed through a die.  Both the forging and extruding processes compress the metal greatly and cause it to work harden.  These bars are then progressively rolled down, then progressively pulled through dies of various sizes until the final dimension is reached.  Annealing may once again be necessary to achieve a specific hardness.  Particular requirements, if known, should be specified as to dimension, tolerances, tensile strength and elongation.

Tubing
A third basic form is tubing, which may be produced in several ways.  Once again, drop shot is melted and if an extruder is to be used, an appropriately sized billet is cast.  The billet is then bored out through its center and at the same time is pushed over a fixed plug mandrel and through a die to create proper dimensions of outside and inside diameter.  Tubing may also be drawn from sheet, which is rolled to an appropriate thickness, a disc is cut from the sheet, the disc is progressively cupped and is then drawn through a series of dies which determine the outside diameter, while a series of mandrels inside determines the inside diameter and wall thickness.  The final tube produced from the drawing process is the result of a number of passes through successively smaller dies and in conjunction with different sized mandrels.  Some small-diameter, thin-walled tubing is made by first producing strip of an appropriate thickness and width, then using a drawplate to bring the strip into tubular form with a seam along the entire length of the tube, then welding the seam.  Round, square, and specialty-shaped tubing may be produced if dies are available.

Conclusion
Suppliers can often times produce specialty forms if provided with accurate specifications, sufficient time and an adequate budget.  As in most instances, small quantities can be produced, but at a much higher unit cost.  Before going to the trouble and expense of ordering specialty items for a particular project, you might wish to consult with a colleague or your supplier, as they might be able to suggest ways of using more standard products which would still allow you to achieve your goals, but in a more cost effective manner.  Platinum in its various alloys, forms, shapes and with its specific characteristics, offers the jeweler a wide range of opportunities to practice the jeweler's art.  However, to fully utilize platinum as a jewelry medium, you must educate yourself and gain knowledge as to how to effectively work in platinum.  There are a number of publications available to help you gain some of this knowledge.  Get a mentor, if possible.  Ask questions.  Do research.  Get with platinum.  Just do it.

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The Supply of Platinum in Semi-Fabricated Form to the Jewelry Industry
Carl P. Denney, Jr.
Johnson Matthey

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