Letter backs
The letter back is the flat panel at the back of a channel letter, cut to the letter shape; the return is fixed around its edge and the lighting is mounted on it.
What the back does
A channel letter is built like a shallow box. The back is the bottom of the box: the return is attached around its edge, the LED modules are mounted on it, and the finished letter is fastened to the wall or raceway through it.
| Letter type | Typical back material |
|---|---|
| Front-lit channel letters | aluminum sheet (often about 0.040 to 0.063 in) or aluminum composite (ACM, often 3 mm) |
| Reverse (halo-lit) letters | clear polycarbonate or acrylic, so the light can shine out the back onto the wall |
| Non-lit letters | aluminum, ACM or PVC, depending on the build |
These are typical choices. The right material depends on the letter size, the lighting and how the sign is mounted.
Shape and holes
- Shape. The back follows the letter outline. Many shops cut it to the same outline as the return so the return sits on its edge; some cut it slightly larger or smaller to suit how the return is attached.
- Holes. Backs usually need a hole for the power wires and small drain (weep) holes at the bottom of each letter so water can get out. Mounting holes are added for studs or for the raceway.
- Counters. The open center of an O, A or R has its own inner return. The back follows the same shape, with the counter cut out.
How shops cut them
Backs are cut on a CNC router (aluminum, ACM, PVC) or sometimes on a laser (acrylic). Because every letter is a different shape, nesting them well on the sheet saves a lot of material on bigger jobs.
How NestSigns handles it
NestSigns nests letter backs from your design file onto full sheets and leftovers, keeps the spacing for your bit, and numbers every part in the layout summary PDF so the backs can be matched to their letters after cutting.
Related: Channel letters · Returns · Trim cap · Aluminum composite nesting · All glossary terms
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