Another beautiful way to imprint promotional products, etching is often mistaken for engraving. Though the results are similar, the process behind the two are totally different. Engraving uses either a graver (can be a rotating carbide cutter or a diamond drag) or laser to cut into metal and other hard-surface items. Etching, on the other hand, uses strong acids or other abrasives to cut into the unprotected parts of the substrate. The most common use for etching is on a metal or glass surfaces.

How It's Done

Etching Metals
The metal to be imprinted is coated with an acid-resistant substance (also called a resist, it is usually a waxy ground). The etcher then exposes the image to be imprinted.

Traditional methods of exposing an image utilizes an etching needle or an échoppe for sloped lines. Today, most etching companies use photographic means. A photo-negative of the artwork is prepared. This image is then exposed on the photo-sensitive surface of the metal. This step results in exposed and a protected metal portions.

The metal then goes through an acid bath or an acid wash. During this process, the acid eats away at the bare metal leaving a fine image on the surface of the product. This process is called "biting".
Once the image has successfully been transferred onto the substrate, it is washed over with water. Finally, the resist is removed with a solvent.

Etching Glass
There are two ways to etch glass:

First, glass etchers can either use acidic, caustic or abrasive substances. In the 1920's, manufacturers developed the mold-etch process to significantly reduce costs for labor-intensive glass etching. Here, art is etched directly onto the mold so that each piece cast from it comes out with the image already etched on the glass. This process involves extremely hazardous acids, so most etchers still prefer the use of abrasive elements. Fluoride compounds are the most popular abrasives used for glass.

The second way to etch glass is with a sand blaster. The glass is covered with a template that has a design cut out of it. When blasted with silicone sand, only the unprotected portions are etched into the glass.