Gild aluminum

When gilding aluminum, there are various techniques that are eligible. They all have advantages and disadvantages. Below we describe the different ways to gild aluminum.

Gilding techniques

Gilding can be done by different methods. The following gilding techniques are the most important:

  • fire gilding
  • cementation
  • galvanic gold plating

The fire gilding

Gilding is a technique that the ancient Egyptians already knew. They applied a layer of lead and gold dust to the metal work piece to be gilded. Then the workpiece was heated until the lead evaporated.

A homogeneous, thick layer of gold remained behind. The Romans refined this technique and used mercury rather than lead. Although this technique is extremely harmful to health, it can be used to achieve really thick and colorful gold layers.

The cementation can be done by yourself

It is a gold plating technique that you can apply inexpensively even at home. In an ionic solution, base metal ions displace noble metal ions. As a result, the noble metal ions settle on the workpiece in the solution. Research has shown that this technique was used many thousands of years ago in South America in what is now Peru.

Disadvantage of cementation

The disadvantage of this gilding is the fact that the aluminum is only coated, but does not bond with the gold. In addition, the gold layer is extremely thin and therefore also weak in color and in their uniformity not one hundred percent satisfactory. Mechanical influences lead to rapid wear.

Improve the properties of the gold layer

The gold layer could adhere slightly better if the workpiece were heated to at least 700 degrees. However, depending on the aluminum alloy present, the melting point is between 580 and 680 degrees, so it can not be used for most aluminum alloys. Therefore, this technique is only recommended on aluminum, if the component is not exposed to mechanical impact.

The galvanic gold plating of aluminum

This process is the technique most used today for gilding metals and even plastics. The basis is the electroplating. In this case, the respective solution with 5 to 10 volts is energized and gilded the workpiece to be gilded by means of immersion baths of different lengths.

The complete process of galvanizing aluminum

This technique of gilding also corresponds to the coppering, nickel plating, brass or chromium plating of aluminum. As with chrome plating, galvanic gilding also requires several steps, including copper plating.

  • Pickling, stripping, degreasing of aluminum (also the oxide layer)
  • Coppering the aluminum
  • Polishing the aluminum
  • possibly repeated repetition of the two previous steps
  • possibly a nickel plating
  • then the polishing again
  • finally the gilding

The polishing of aluminum is an important step that needs to be repeated over and over again because the surface of the workpiece must be absolutely smooth and clean. Even the slightest scratches during massive later to see.

Task of partly multiple copper plating

To a certain extent, such defects and damage can be eliminated by repeatedly performing the coppering and subsequent polishing of the aluminum. However, this also increases the time and effort (by the coppering and polishing).

Advantages and disadvantages of galvanizing aluminum

However, galvanic gilding has the advantage that it adheres very well even under mechanical stress. However, due to a chemical reaction (sulfur through the metal pores), a blackening may occur, which is why sealing may be advisable after galvanizing if the visual effect is to be the focus for a long time. Hard gold plating is also achieved by the galvanic gold plating of the aluminum.

Tips & Tricks

Since polishing is an important part of chrome plating or gilding, it is worth considering just polishing the aluminum. If a yellowish shimmer is desired, as in gilding, anodizing could be an alternative. Even exclusive copper plating is worth considering.

Video Board: Gold-plating aluminium - How to gold-plate aluminium by yourself