Three topics are addressed in this report:

1. Demographism, or skin-writing by jewelry alloys. Although the phenomenon of skin-writing affects some individuals, the more prevalent cause of dark smudges on the skin or clothing is wear or ordinary abrasion, which can be accentuated by the presence of tarnish and corrosion films, particularly with low-karat alloys.

2. The development of two new techniques for making dental restorations (crowns and bridges) which may have applicability for jewelry fabrication, particularly for short runs. One technique utilizes optical techniques to survey an object and, through CAD/CAM technology, generate the 3-dimensional machining coordinates to precisely mill an accurate replica of an object with extremely complex geometry. The second technique utilizes gold (alloy) powder to produce a solid object. A paste of powder and an appropriate liquid binder is used to build up an object in much the same way as a wax model is made. Without prior mechanical compaction, the “green” object is sintered to produce a strong, solid device with accurate fit and low porosity.

3. Jewelry fabrication trials with 990 Gold, an alloy of 99 w/o gold and 1 w/o titanium which can be hardened by simple heat-treatment. The response of the alloy to thermal processing and cold work are discussed, as well as forming, joining, and refining the alloy. Comparisons of the properties of 990 Gold (23-3/4k) to lower karatage (e.g. 18k, 14k) gold alloys indicate its strength and durability are comparable to ‘traditional’ jewelry alloys, unlike 24 karat gold which is soft and not durable.

Author: Arthur M. Tasker