The Laboratory At The Birmingham Assay Office
PLATING THICKNESS DETERMINATION
This test is used to determine the thickness of plated layers. It can be conducted by either destructive or non-destructive methods
SULPHUROUS AGENT TARNISH TEST
This test is appropriate for articles that have received special treatment (such as a protective coating, intended to minimise the effects of attack by sulphur bearing compounds), to test the effectiveness of the treatment. The test exposes the item to the three most common accelerants of tarnishing which may be encountered during packing, transport, storage and in store display. These are sulphur, humidity and temperature. An assessment is then made of the resistance to tarnishing.
The surface/coatings of the sample are exposed to controlled conditions of humidity and temperature by heating and cooling them in a specially designed chamber. The degree of corrosion or deterioration of the coating and/or of the substrate is used to assess the level of resistance of the surface/coating to the test conditions.
SYNTHETIC SWEAT/ PERSPIRATION TEST
This test determines the resistance of articles to prolonged contact with perspiration.
ULTRAVIOLET LIGHT TEST (Sun Radiance/Humidity/Temperature)
The article is subjected to conditions of high humidity and temperature and exposed to UV rays for a period of 72 hours. Colour changes to the surface and surface appearance, as a result of exposure to UV rays are assessed, both by visual and spectrophotometric measurement, where possible. High quality photographs are also used for judgment purposes.
POROSITY TEST This test gives an indication of the quality of the gold, rhodium or platinum coating on a base metal alloy. Its purpose is to highlight any corrosion of the base metal alloy in areas where there are inconsistencies in the surface coating.
CHLORINATED AGENT TEST
This test simulates exposing gold/silver plated/unplated articles and watches to a swimming pool environment. Colour changes to the surface are assessed, both by visual and spectrophotometric measurement, where possible. High quality photographs are also used for judgment purposes.
To assess whether stones in stone set articles are adequately set or glued to the setting by using a tape adhesion method and/or ultrasonic stone adhesion procedure.
Determines the reaction of articles to severe temperature changes. Articles are exposed to drastic fluctuations in temperature, then the surface is examined for signs of blistering or detachment under 10 x magnification.
IMPACT DROP TEST
Establishes the resistance to adhesive failure during impact on stones (includes glass, plastic and metal posts and inserts) glued in the settings.
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