Installing Peepholes in Fiberglass Doors

Fiberglass: Don't treat it as wood!

If there is a drawback to fiberglass, ironically it's that it's not quite the same as wood. Meaning, the exterior resemblance is flawless, but the interior is still glass and plastic. While it is relatively easy to drill a hole in wood to install a peephole, the task is a bit more difficult for fiberglass exterior doors. The basic procedure is the same however, in that you will need to drill a hole in the door.

Test the surface

Before drilling, begin by using another tool to make a indentation in the surface of where the peephole is to be installed. After making an indentation, use a steady and slow drill, without applying a lot of force. Some people have suggested taping over the surface to reduce the amount of chipping, but others have found this ineffective.

Go slow

You're just going to have to go much slower, taking care not to cause any chipping or cracking. The danger is that the glass material can chip if the drill bit is applied incorrectly. To prevent this, start off the drill at a shallow angle to experiment and see if and how the chipping occurs. You may also need to avoid tearing off the finish and coat. These are things you just never worry about with wood.

Enlarge the bit

Now move on to a slightly larger bit to enlarge the hole. Keep the rotation speed low and do not apply a lot of force. Rinse and repeat to get the peep hole you require. What type of bit should you use? Watch out if you're not using a carbide bit. Solid fiberglass will make it dull, rendering the bit quite useless in drilling something especially as hard as fiberglass.