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How to Seal Metal With Lacquer Coating for Conservation

In "The Conservation of Marine Archaeological Objects," marine archaeological conservator Colin Pearson, Ph.D., says, "excavation without having conservation facilities available is vandalism." Using lacquer in metal conservation is based on a commonsense argument: Lacquer prevents oxygen in the air from binding to, and borrowing atoms from, the molecules of metal. This means that the conservation process is one of cleaning, rinsing and coating the material to be conserved.

Things You'll Need

Denatured ethanol
De-ionized water
Litmus strips
Sodium bicarbonate

Instructions

- 1
  The metal should be rinsed in several individual baths of denatured ethanol (ethyl alcohol) or hot de-ionized water. If you use water, use litmus strips to check the pH of each separate water bath following each rinse. Water tarnishes copper, so use a wet paste made of denatured ethanol and sodium bicarbonate (baking soda) to remove the tarnish from copper.
- 2
  Polish the metal to the extent that you desire.
- 3
  Soak the metal in a solution made from ethanol or water, and benzotriazole (BTA) in a concentration ranging from 1 to 3 percent, after all cleaning and stabilization of the metal has been completed and the metal has been polished. The Conservation Research Laboratory at Texas A&M University recommends a 3 percent BTA solution.
- 4
  Rinse the metal in acetone to remove the BTA and allow the acetone to evaporate. Coat all surfaces of the object with a clear acrylic lacquer spray.

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