Standard channel letters
A standard channel letter is a three-dimensional graphic sign element. Its channel is fabricated from sheet metal, most often aluminum since it does not rust. A flat sheet of aluminum is typically cut on a table by a computer-controlled router. This creates the back of the channel and is the basis for the letter shape. The sides of the channel letter, called the returns, are then formed by bending a 3 to 6-inch-wide (150 mm) strip of aluminum sheet around the aluminum back. This return can be welded at the seam or flanged and riveted or, with a metal stitcher, can be fastened with galvanised or stainless wire to the back to create a solid can in the shape of the letter. The letter can is painted and fitted with any lighting components necessary such as neon gas tubes or light-emitting diode (LED) modules. A translucent plastic face usually of 3/16″ thick sheet acrylic fibre or polycarbonate or lexan is cut to fit the open face of the letter can. A trim cap border is applied to its edges which gives the letter face a finished appearance and creates a fastening surface to attach it to the letter can. When illuminated at night, channel letters draw the eye of passers-by.
Channel letters may be flush mounted (attached directly to the building facade), or they may be mounted on a raceway or wire-way. A raceway is a rectangular mounting structure which serves as both a container for the sign’s electrical components (such as a power supply) and a mounting structure.
A wire-way also serves as a mounting structure but typically contains only wiring. It is thinner and broader than a raceway, and may also be used as a backer panel for the channel letter set.
Exposed neon channel letter
These are standard channel letters, but the neon is covered with a clear acrylic face to keep birds from making a nest as well as to protect the exposed neon from outside elements such as weather etc. This allows for the exposed neon to be seen, as well as the inside of the channel letter interior itself to add to the dimensional look.
Reverse lit channel letter
In this letter type, the face of the letter is constructed from aluminum and the lighting is directed to the back. This light floods the wall that the letter is mounted to and creates a negative space at night. Letters in this style are also called halo letters. It is usually the most expensive form to manufacture.