Stuller cast platinum products are made from a 95/5 Platinum-Cobalt alloy. Because this alloy behaves differently than 90/10 Platinum-Iridium alloy, we wanted to give you the following tips on using the metal.

Since cobalt is ferromagnetic, like iron, this alloy is slightly magnetic. You should avoid contamination of piece with magnetized bench scrap.

The melting temperature of this alloy is 1765°C (3209°F), compared to 1800°C (3272°F) for 90/10 Platinum-Iridium alloy. This difference makes fusing the two alloys practically impossible.

When sizing a shank made from this alloy, use a 1700°C solder. When joining this alloy to gold, use cadmium-free karat gold solder. Cadmium will migrate into the grain boundaries of this alloy, causing brittleness.

This alloy will tarnish (oxidize) during soldering. Do not coat the piece with boric acid prior to soldering, as this will lead to brittleness and breaking along the joint. After soldering, coat with boric, heat to approximately 1200°F (low red color), and pickle to remove oxides.