How Etched Plaques and Signs are Manufactured

Etched Plaques and Signs

Etched plaques and signs have this rather attractive, 3-dimensional look to it mainly because of the grooves and raised portions of the sign. Ever wonder how these grooves were made cleanly into the metal used for the sign or the plaque? Believe it or not, these grooves and raised portions are actually made with the use of acid.

In the old days, the creation of etched metal was for printing plates. These days, the creation of these metal plates was for a variety of uses, some of which include signage and commemorative plaques. The creation of such metal plates in the past were also done by hand, with artisans creating the designs on zinc or copper plates with the use of a pointed etching needle scraping off some of the waxy covering protecting the metal.

These days, when etched signs and plaques are created, computer assisted machinery is now used. This type of marking procedure effectively combines computer aided design with chemistry and metallurgy. The result is often a clean and precise representation of the design marked into the metal with the use of a mordant or acid that eats into the chosen metal.

In the old days, wax was used to protect the parts that were to be raised on the metal and the exposed parts were to be the grooves in the design. These days, what people use to protect the parts that are not to be eaten by the acid is a protective coating called a photo-resist coating. This is applied to the metal much like when a photo is developed onto paper, with the use of a negative created of the design needed for the plate.

This sheet with the photo-resist coating is then dipped into an etchant, which can be an acid or any other chemical that can eat through the metal. The longer the metal plate is submerged in the etchant, the deeper the grooves will be. Other factors that also affect the finished product include the strength of the acid used, the temperature of the acid bath and other similar factors.

When the etching is done, the metal plate is then removed from the solution and rinsed off to stop the biting action of the acid on the metal. The protective coating is then removed and the finished plate is either sent for painting or to the client as is, depending on what the customer ordered, of course.