Gold plating is a process that involves applying a thin layer of gold onto the surface of another metal. The gold plating gives the base metal an attractive golden appearance while being much more affordable than solid gold. But not all metals are suitable for gold plating. The base metal must have certain properties to allow the gold layer to properly adhere and last.

Best Metals for Gold Plating

While gold plating can be done on many metals, some are better choices than others. The key factors that make a metal suitable for gold plating include:

Corrosion Resistance – The base metal must not oxidize or tarnish easily to avoid affecting the gold layer.
Solderability – Soft, malleable metals that can be soldered or welded allow for pre-plating work.
Adhesion – The gold layer must properly fuse with the underlying metal for lasting results.
Conductivity – More conductive metals allow the gold to plate evenly and smoothly.

With these factors in mind, below are the top metals used in gold plating:

Silver

Silver is one of the most popular metals for gold plating. It has excellent conductivity and reflectivity, which allows the gold to adhere evenly and take on a brilliant lustre. Silver naturally resists tarnishing and has a bright white sheen, making it an ideal base for gold plating. Additionally, silver is very malleable and easy to work with.

Gold-plated silver is commonly used for jewelry, cutlery, decorative pieces, and awards/trophies. The gold enriches the elegant look of silver. Combining these precious metals allows for unique, high-quality items.

Copper

Copper is an affordable metal that gold plates well. It is highly conductive, which ensures smooth and even plating. Copper has a reddish-orange finish that turns a luxurious shade of gold when plated. Items made of solid copper can be heavy, so copper that is gold plated is often thinly-layered or plated onto a more lightweight base.

Gold plated copper is ideal for jewelry, wiring, electronics, and decorations. It provides an inexpensive alternative to gold plated silver. However, copper does oxidize over time, so a nickel under-plate is sometimes applied first to protect the gold finish.

Brass

Brass is an alloy of copper and zinc that offers many of copper’s benefits – good conductivity and solderability along with greater strength and hardness. Brass has a bright golden-yellow finish that takes well to gold plating for an enhanced look.

Gold-plated brass is widely used for smaller decorative pieces, jewelry findings, hardware, and accents. Brass is also popular for musical instruments and other items where the combination of gold’s beauty and brass’ acoustic qualities are desired. An electroless nickel plate may be added to brass first to protect the soft gold layer.

Nickel

Nickel is often used as a base layer before gold plating other metals, especially copper alloys like brass. The nickel provides corrosion protection and enhances the foundation for the gold to adhere well. However, nickel can also be plated directly with gold for items like electronics, hardware, and even some jewelry.

Nickel has a silver-grey appearance that gives a different, darker hue from the warm gold finish. This contrast can create depth and visual interest. The hardness of nickel also helps protect the thin gold coating.

Stainless Steel

Stainless steel has become a popular material for gold plating, especially in the fashion jewelry industry. Stainless steel itself has a modern, sleek look. Combining it with gold adds elegance and sophistication. Stainless steel is very hard and durable, so it must go through special preparation processes including activation and strike plating before gold can properly adhere.

Gold-plated stainless steel is widely used for jewelry, watches, accessories, and other decorative pieces. It provides an affordable alternative to solid gold jewelry. The hardness of stainless steel protects the gold finish from rubbing off.

Other Metals

Some other metals can also be plated with gold, but may provide less than ideal results. These include:

Iron/Steel – Can rust without sufficient under-plating. Gold adheres poorly.
Aluminum – Very reactive and oxidizes easily. Needs special pre-treatment.
Titanium – Extremely inert surface makes gold plating difficult.
Tungsten/Cobalt – Brittle, very hard to work with. Difficult to gold plate evenly.

So while it is possible to gold plate many metals, silver, copper, brass, nickel, and stainless steel tend to provide the best results and are most commonly used.

How to Prepare Metals for Gold Plating

To achieve quality gold plating results, the base metal must be properly prepared first. The steps include:

1. Cleaning – The surface must be free of oils, dirt and oxides. It is chemically cleaned to remove residue.

2. Activation – On metals like stainless steel, an activation solution etches the surface to allow gold to adhere.

3. Striking – An initial plating with copper, nickel, or silver enhances subsequent plating steps.

4. Neutralizing – After each step, the metal is rinsed in a neutralizing bath.

5. Plating – The gold plating solution is applied using electric current to coat the metal.

6. Testing – The plated item is tested for proper gold thickness and coverage.

7. Polishing – A polishing cloth or buffing wheel can be used to brighten the gold’s shine.

8. Sealing – A clear sealer is sometimes applied to prevent wear and exposure of the base metal.

Proper preparation and plating processes allow the gold layer to fuse correctly to the underlying metal. Rushing the steps can lead to poor plating quality.

Gold Plating Methods

There are several techniques that can be used to apply the gold plating:

Electroplating – The most common method. The metal piece is submerged in a gold plating solution and electric current coats the surface with gold.

Electroless Plating – No electric current is used. The gold plates via a chemical reaction. Often used for pre-plating.

Brush Plating – The plating solution is literally brushed onto the surface for small repairs or touch-ups.

Vacuum Plating – Done inside a vacuum chamber. Useful for plating irregular shapes.

Immersion Plating – Very simple method of dipping an item in gold solution, but results in uneven plating.

Spray Plating – The gold solution is sprayed on using a special spray gun. Only practical for very large pieces.

Electroplating allows the smoothest, most even gold layer and works on almost any properly prepared metal surface.

Gold Plating Problems and Repairs

Gold plating has the potential for problems to occur including:

Peeling or flaking of the gold layer
Tarnishing or discoloration
Visible scratches exposing the base metal
Uneven plating thickness
Low karat gold used

Many issues can be avoided with proper metal preparation and using quality plating solutions. But some problems may still arise over time.

For minor repairs, brush plating can be used to touch up scratches or thin spots. More significant damage like large areas of missing gold require stripping the old plating and re-doing the process.

Proper gold plating care – avoiding harsh chemicals, impacts, and abrasion – helps maintain the gold finish. Regular polishing will also keep plated items looking their best.

Gold Plating Cost Analysis

The costs of gold plating include:

Equipment – For commercial plating, large plating tanks are needed requiring big investments. For small operations, smaller electroplating machines are available at more reasonable prices.
Materials – The plating solutions with gold compounds can be expensive, especially for higher karat solutions.
Labor – There is skill and labor involved in properly preparing each piece and monitoring during plating.
Volume – Plating costs are fixed, so doing larger volumes lowers the per unit cost.
Karat – Higher karats require more gold content in the plating solution, increasing material costs.
Thickness – Gold layers over 1 micron add substantial gold usage and cost.

For a 10-20 piece jewelry line, gold plating may cost $30-$50 per item. For a large production run, costs could be $5-$10 each. Unique pieces or special platings will be more expensive.

Is Gold Plating Worth it?

Given the costs involved, is gold plating ultimately worth it? The answer depends on your specific needs.

Gold plating makes sense for:

Businesses selling affordable gold-looking jewelry, accessories, trophies, etc.
Adding a luxury touch or accent details to products.
Electronics and other applications where durability is needed.

The costs of solid gold would be prohibitive in these cases.

However, gold plating may not be worth it for:

Fine jewelry where the karat gold content is important.
Small productions with no economy of scale.
Pieces that will receive heavy, abrasive use.

For many applications, gold plating provides the ideal balance of appearance, durability, and affordability.

Conclusion

Gold plating allows almost any metal to take on a brilliant gold finish, making it extremely versatile. While a wide range of metals can be plated, the best results come from conductive, non-corroding metals like silver, copper, brass, nickel, and stainless steel. With proper preparation and plating methods, gold-plated items can have beautiful, lasting shine. For applications where solid gold would be unrealistic, gold plating offers an affordable alternative.

References

A. Kenneth Graham, Electroplating Engineering Handbook (Springer, 1971) – A key plating reference covering the technical details of preparation, plating processes, testing, and troubleshooting.
Gold Plating Services Information Site (GoldPlatingServices.com) – Provides overview information on gold plating methods, suitable metals, and cost considerations.
Julie Sartain, “The Gold Plating Process Explained” (Electronic Design, 2012) – Outlines the basics of gold plating and electroplating processes.
Christina B. Farmer, “A Review of Gold and Gold Alloys Use in Jewelry Products” (MRS Bulletin, 2019) – Discusses properties of gold alloys and plating for jewelry applications.
Shiva Hullavarad, “Gold Plating” (New Age International Publishers, 1996) – A technical guide covering best practices for gold plating different metals.
George Dubpernell, “Gold Plated Metals for Jewelry Making” (Jewelry Making Journal, 2015) – Reviews metals like silver, copper and brass for gold plating jewelry.
Lisa Marlin, “How to Care for Gold Plated Jewelry” (The Spruce Crafts, 2022) – Provides tips on caring for and maintaining gold plated jewelry pieces.
Calla Gold, “Gold Plated vs Gold Filled Jewelry” (Calla Gold Jewelry, 2020) – Comparison of gold plating versus gold filling processes and results.