Choosing a Fine Jewelry Plating Solution
In selecting an electrolyte and plating system, it is good practice to seek advice from P AND S Chemitech, [AB1] your plating materials supplier. We can advise on what is most suitable for your needs. Plating, of course, removes gold from the electrolyte. Therefore, it is important to maintain the correct concentration of salt in the electrolyte. Additions of salt should be made periodically. This requires an ability to measure the gold concentration in the bath.
Jewelers have many reasons to plate jewelry, such as achieving two-tone designs, producing model masters, adding scratch and tarnish resistance and creating sample pieces for their customers. Yellow gold plating solutions are available in a variety of karat colors; as the karat color rises from 14- to 24-karat, [AB2] the color deepens and becomes richer. In addition to yellow gold plating solutions, rose gold, pink[AB3] , platinum (white undertones), palladium (grey undertones), white rhodium, black rhodium, and black ruthenium plating solutions are also available.
Plating thickness is the next decision when choosing a solution. The type of piece—ring, pendant, bracelet, etc.—sets the wear and determines the minimum thickness of plating you'll need. Be aware that quick flash plating [AB4] does add color but leaves a thin coating that will wear off many pieces. If the jewelry piece is a hard-wear item like a ring, you may want to think about a heavy deposition solution; for earrings and jewelry that does not see a lot of wear, a regular submicron plating should be fine.
For jewelry application, a deposit thickness of about 0.5 – 5.0 microns is typical, but very thin ‘flash’ coatings may be used where cost is more important than quality. If one is gold plating onto base metals, it is common practice to first electroplate with a thin ‘flash’ or ‘strike’ coat of copper to provide a good key, then an undercoat of nickel, bronze or tin. The purpose of these underlayers is to provide levelling and brightening to the substrate and to inhibit migration of underlying copper into the gold layer. With the European Directive against use of nickel, there is a trend to use bronze (copper-tin – zinc[AB5] ) or palladium as the underlayer. Often, a ‘strike’ gold layer is then deposited of about 0.1 microns thickness before the full gold layer is electroplated from a different gold electrolyte.
Subcontracting your Jewelry Plating. What if you have an idea for a custom design and want to add plating to a single piece of jewelry or several pieces? You can purchase the plating equipment [AB6] , but the equipment involved to plate a single piece of jewelry is extensive and may not be worth the investment. Along with the financial cost, the time to learn the plating process may not be best for short-term use. Your search ends here … P ANS S Galvasols[AB7] is here to help you meet your demand.
Pen-Plating [AB8] in Jewelry Making.
To add selective areas of plating to jewelry, pen-plating could be the right choice for your business. With these systems, a pen is dipped into the pen-plating solution then rubbed onto the metal, dipped again and rubbed, until it reaches the level and area you want plated.
Steps for Professional Jewelry Plating
Plating steps are similar but not exactly the same for all metals. Base metals in particular have additional steps and usually need to be pre-plated before a final plating with precious metal.
Finish the piece to remove imperfections that may be amplified when plated. No matter the reason for using plating, proper preparation is the key to professional-quality results. Buff and polish the piece before plating. A layer of shiny gold points out flaws, and you'll find yourself needing to remove the finish you just applied and starting over. Plating does not fill in pits or scratches in your jewelry.
Clean in an ultrasonic cleaner [AB9] to remove grease, polishing compounds, etc. Rinse in distilled water.
Clean in an electro cleaner solution heated to 150° F using a stainless-steel anode; clean at six to twelve volts. Rinse in distilled water.
Dip in an acid bath[AB10] . Rinse in distilled water.
Follow the plating sequence guide [AB11] for the material of your piece and jewelry plating solution you are using.
Jewelry Plating Best Practices (needs elaboration?)
When you switch from one plating solution to another, put the first solution back in its original bottle; the bottle should be labeled with the solution, plating instructions, and warnings.
Detailed Pages [Rh, Ag, Pt, Pd]
Virtually all white gold jewelry is rhodium plated. It is often referred to as dipping because a part of the process includes dipping your jewelry into a bath of rhodium. Rhodium, a platinum metal, wears off with time, especially on the backside of rings and on the tops of the prongs.
Rhodium is a platinum group metal with a good white color and is hard and tarnish resistant. For jewelry purposes, we desire a bright deposit, defect-free and hard and there are several suitable rhodium plating systems on the market. These are sulphate type baths and are very acidic.
Usually, deposit thickness of about 0.5 microns, but up to 2-3 microns, is plated on gold jewelry to give the required surface characteristics. There is a tendency for internal stress to build up in the deposit as thickness increases, resulting in cracking eventually.
For the high carat golds, a thicker layer of rhodium is plated directly on the substrate, but for low carat golds, a nickel interlayer is plated first, allowing a thinner, cheaper rhodium deposit without losing color and providing good corrosion resistance.
Silver plating (Ag)
Silver is a soft, lustrous metal that is very malleable and silvery-white in color. Sterling silver is a common alloy comprised of 92.5 % silver and 7.5 % copper. To plate in a silver color we usually recommend to plate your article in nickel and then in rhodium (a platinum metal), resulting in a bright white color.
Platinum is a dense, malleable metal that is white in color with cool undertones. It is almost always used in its purest form in jewelry, 95%. Platinum is substantial in weight. Comparatively, a ring in platinum will weigh almost 60% more than the same ring in 14kt gold. For these reasons a platinum ring is significantly more expensive than the same item in a gold alloy.
Palladium is a member of the platinum metal group and is a soft, silvery-white color with slightly gray undertones. It is also used in an almost pure form in jewelry, 95%.
[AB1]Link to P&S Home Page
[AB2]Link to Gold Plating Solution
[AB3]Link to (Micron) Gold Plating Solution
[AB4]Link to Flash Gold Plating Solution
[AB5]Link to Bronze Plating Solution
[AB6]Link to Plating Equipment
[AB7]Link to P&S Galvasols
[AB8]Link to Pen Plating Solution
[AB9]Link to Ultrasonic Clear
[AB10]Link to Acid Bath
[AB11]Link to Plating Sequence Guide