General Plating Procedure Instructions
For Nickel, Gold, Silver and Rhodium
Articles which are to be plated must be cleaned thoroughly after polishing to remove all possible contaminants. Ultrasonic cleaning with a solution of water, liquid soap and ammonia is best. If ultrasonics are not available, then boil your pieces in the same mixture of cleaning solution for about 30 minutes.
After cleaning, the articles should be rinsed in running water to remove all traces of the previous soapy solution. If you are not certain that the jewelry is absolutely clean, you should give it the "water-break" test. In this test, water is run over the surface of the article. If it forms a smooth, continuous, unbroken film coating the entire surface, this indicates that all greasy substances have been removed. If, on the other hand, the film of water is broken into separate streams or droplets, then the article has not been sufficiently cleaned and should be returned to the soap-water-ammonia cleaning bath.
With the voltage of the rectifier set at 10 volts (different plating people use different voltages, anywhere from a low of 6 volts to a high of 15 volts) and the electrocleaner solution at 190½ F, clip the negative (-) black wire to the plating rack and immerse the rack in the electrocleaner solution for 30 seconds. Unclip the rack. (Excessively long immersion will darken the metal).
Dip the rack with the jewelry into the running-water rinse-tank to rinse off the electrocleaner from the rack and from the jewelry.
If nickel plating is required, then set the rectifier at 1½ to 2 volts with the solution between 120½ F and 140½ F. Clip the negative (-) black wire to the plating rack. Immerse the rack in the nickel plating solution for several minutes. Agitation of the rack in the nickel plating solution is highly recommended. Experiment with various lengths of time from 3 minutes to 10 minutes to determine that time which is best for you. Unclip the rack.
Rinse the nickel plating solution from the rack with the jewelry in the running water rinse-tank.
If the gold plating is required, then set the voltage of the rectifier at 3 to 4 volts with the solution at 1000 F. Clip the negative (-) black wire to the plating rack. Immerse the rack for 30 seconds to 1 minute. Unclip the rack. Dip the rack with the jewelry into the gold-dragout glass jar. The liquid gold solution which clings to the rack and to the jewelry will come off into this jar and not be lost. For a thin coating of gold plating, (flash plating) use Shor standard gold plating solution. For a heavy coating of gold plating, use Shor Heavy gold plating solution with titanium anodes instead of stainless anodes and have the solution at 800 F to 1000 F with 1½ to 2 volts. Moderate agitation is recommended.
Dip the rack with jewelry into the running-water rinse-tank.
If rhodium plating is required, then set the voltage at 6 volts with the rhodium plating solution at room temperature. Clip the negative (-) black wire to the plating rack. Immerse the rack in the rhodium plating bath for 30 seconds to 1 minute. Unclip the rack. Dip the rack with the jewelry into the rhodium dragout glass jar. The liquid rhodium which clings to the rack and to the jewelry will come off in this jar and not be lost. The "force" with which the rhodium is thrown at the article is determined by three factors: The voltage, the temperature, and the relative size of the anode to the work. The higher the voltage, the higher the temperature, and the larger the anode with relation to the work, the greater is this force. These three factors must be kept within near-perfect balance so that the force will not be too great or too small. Too great or too small a force will result in an unsatisfactory plate. It should be clear that the temperature can be increased simultaneous with a voltage decrease (or vice versa) without changing the force. There is, therefore, a wide range of conditions under which rhodium can be successfully plated. For example; plating can be done at room temperature (approximately 700 F) at 6 volts; or at 1000 F at 2 volts. Using platinum anodes or platinized titanium anodes and with the electric current turned on, the plating rack with jewelry is immersed in the rhodium plating solution. It is taken out every few seconds for inspection. With each immersion the brightness of the plate will increase until a maximum brightness has been reached. After this, there will be rapid darkening with each additional immersion. The optimum plating time must be determined by experience. Excessive force (resulting from a combination of excessive temperature and/or voltage and/or anode size) results in a dull plate. When the article is kept too close to the anode a brown "burn" mark results.
If silver plating is required, do not plate at a temperature above 65½ - 75½ F. To achieve the desired voltage, set up the voltage after the work is i the bath. Plate small items at 1 ½ volts for between 15-60 seconds, keeping the work in motion. Larger pieces should be plated at 2 volts. At 15 second intervals, check the work so you can be stop the plating process when the desired plating results are achieved.
Dip the rack with jewelry into the rhodium-dragout glass jar.
Dip the rack with the jewelry in the running-water rinse-tank.
Using coated steaming-tweezers, hold each piece of jewelry, one at a time, under a blast from the steam machine. This will dry the jewelry, avoiding water stains. It will also give the jewelry a high shine.
When the rhodium-dragout glass jar contains enough rhodium plating solution, it may be poured into the regular rhodium plating solution to replenish it. (The same is true for the gold-dragout jar replenishing the gold-plating solution).
Many solutions come in concentrated form, requiring that you add water. Electrocleaner comes in powder form, requiring that you add water. The water for all solutions must always be distilled water. One pound of Shor electrocleaner powder makes 4 gallons of electrocleaner solution. There is no test to determine when to discard the electrocleaner solution. Very busy factories discard the solution every day. Less busy factories discard the solution every week. Those with little plating activity discard the solution every month.
Nickel plating solutions which do not work properly after some time can be tested only by experienced platers and then corrected. For small volume plating shops the most practical methods are as follows: a) Test with the "pH" papers. If the "pH" is below 3, then add 1 cc. of chemically pure sulfuric acid to bring the "pH" up to 3. b) Stir the nickel solution. Wait 5 minutes. Now test the "pH". If it is still below 3, add 1 c.c. of sulfuric acid. The other correction you can make is to add 10 cc. nickel brightener and stir. If plating is not improved, then add another 10 c.c. of nickel brightener and stir. If the problem is still not solved, then discard the nickel plating solution and use a fresh nickel plating solution.
Maintenance procedure for rhodium solution is as follows:
Put some rhodium solution (from the normal rhodium plating solution which is in the glass plating jar) into a small glass bottle (about 1 ounce of solution). Put this small bottle in a drawer (so that it is not faded by sunlight). After a few days of rhodium plating, compare the color of the rhodium solution in the glass plating jar with the color of your small sample. If the color of the rhodium plating solution is noticeably lighter, then add rhodium replenisher to your rhodium plating solution until the rhodium plating solution is as dark as your sample.
About once a week (depending on how much rhodium plating you have done) pour the solution through filter paper to clean it of contaminants. Some contaminants will be dissolved in rhodium and cannot be stopped by filter paper. If this happens, put activated charcoal in your filter paper before pouring the rhodium solution through it. The activated charcoal will absorb the impurities. Since it will also absorb some of the rhodium, use the activated charcoal only when necessary.
For more information on rhodium plating, please refer to the Shor instructions for rhodium plating. For rhodium or gold plating with a pen, please refer to the Shor brochure and/or instructions for the Shor Rhodinette.
Some Notes on Rhodium Replenishing and the Use of the Hydrometer
Before using a fresh Rhodium Plating solution fill a one-ounce or two-ounce bottle with. the fresh solution. This small bottle of solution will serve as a standard for color comparison. After the- regular Rhodium Plating solution has been plating successfully for quite a long time, a point will be reached when so much Rhodium has been plated out of the solution that it will be too weak to give good results. There is still Rhodium in this solution. To bring the solution up to proper strength add a sufficient quantity of Rhodium Replenisher to bring the color of the solution back to the color of the solution in the standard comparison bottle. The old solution will now be of proper strength and ready for additional Rhodium Plating.
The purpose of the Baume hydrometer is to test the amount of sulfuric acid in the Rhodium Plating solution. The-mare sulfuric acid in the Rhodium Solution, the heavier will be the weight of the Rhodium Solution, and therefore the higher the hydrometer will float in the solution. Although Rhodium will plate properly when the hydrometer reads any number between # 4 and # 12,-most platers prefer # 8. When the hydrometer reading is too low, add sulfuric acid (chemically pure) drop by drop until you obtain the desired reading on the hydrometer.