Metal Finishing Guide Book

2012-2013

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��� ��� 15 30 ��� ��� ��� ��� 150-180 20-50 2 15 ��� ��� 0.2 2.7 ��� ��� 150-160 30-40 2 15 ��� ��� ��� ��� 0.25 ��� 130-160 10-30 2 15 ��� ��� 1.1 ��� ��� ��� 150-160 30-60 2 15 ��� ��� 0.025 0.13 ��� ��� 150-160 10-35 Gold as potassium gold cyanide (g/L) Free potassium cyanide (g/L) Dipotassium phosphate oz/gal g/L Sodium hydroxide (g/L) Sodium carbonate (g/L) Nickel as potassium nickel cyanide (g/L) Copper as potassium copper cyanide (g/L) Silver as potassium silver cyanide (g/L) Tin (g/L) Temperature (OF) Current density (A/ft2) 2 15 ��� ��� ��� ��� ��� ��� 140-160 10-40 2 15 ��� ��� 0.025-1.4 ��� ��� ��� 140-160 10-40 2 15 ��� ��� 0.025 1.1 ��� ��� 140-160 20-50 2 15 ��� ��� 0.025 ��� 0.05 ��� 140-160 10-40 2 15 ��� ��� ��� ��� ��� 2.1 150-160 30-50 Rose 6 4 Pink 0.82 4 Green 2 7.5 White No. 2 0.325 15 White No. 1 0.4 15 Green 1.25-2 2.0 Pink 1.25-2 2.0 Hamilton Colors Yellow 1.25-2 7.5 Low Cyanide English 1.25-2 7.5 Table I. Gold and Gold Alloy Flash Baths (Classes A and B) 24K or English 1.25-2 7.5 326 4. Cost of control and maintenance. Some high-speed and highefficiency baths require almost constant attendance and analysis. 5. Cost of longevity of the bath. High-speed and especially high-purity baths with good drag-out recovery must be changed periodically to maintain purity. This results in a certain loss on changeover. 6. Cost of money (interest) to keep the bath. 7. Initial cost of the equipment. 8. Overhead cost of the equipment (whether it is operating or not operating), that is, the interest cost per hour or per day. Sometimes, a simple manual rack or barrel method will be cost-effective; at other times, a high-speed fully automated plant is justified. Gold today is a freely traded commodity with a different price every day. To plate successfully it is necessary to watch and control costs. DECORATIVE GOLD PLATING (CLASSES A-C AND, SOMETIMES, G) Much, but not all, decorative plating is applied to jewelry, watch attachments, and other items of personal use and adornment. The thicknesses of gold or gold alloy are usually 0.000002 to 0.000005 in. and the time of plating is 5 to 30 sec. The recommended trade practice rules for the jewelry industry require that this deposit be called gold flash or gold wash. (To be called gold electroplate it is necessary to have a minimum of 0.000007 in.) These deposits are usually applied over a bright nickel underplate and are bright as plated. They do not require any brightening or grainrefining agents. There are hundreds of different colors and hues, but the Class A and B baths, shown in Table I, will give a representative sample of colors. All of the ���coloring��� baths in Table I

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