Making Small Fiberglass Parts
by Larry Bell
(Power Window Switch Pods)
After installing power windows on Project 67, I couldn't find a good location for the switches. So I decided to put them in a small pod that mounts to the door panel. This required making the pod structure out of fiberglass.
The first step is to make a part out of some easily worked material. This will be the exact shape of the finished part. I used high density foam and shaped it using 80 grit sandpaper.
Next, I mixed up a few pounds of plaster of paris. The foam pattern was pushed into the plaster and left to dry. I used butter on the foam as a release agent. After about an hour the part can be pulled from the mold. If you have to destroy the foam it's no big deal. We only have to get two parts from this mold.
The mold can now be filled with fiberglass. The mold was first sprayed with silicone spray as a release agent. I used matting rather than cloth as I find it easier to work with. I made the wall thickness thick enough to be strong and inflexable. After the fiberglass sets up it can be pulled from the mold and the second one can be layed up.
The part won't look perfect at this stage. The flashing needs to be removed and the part shaped using grinders, files, and sandpaper. Any holes can be filled with plastic filler and finished. At this point the fiberglass work is complete and our part is made. You can decide what to do next as far as finishing. It can be primed and painted or in my case covered with vinyl. I used contact cement to hold it on. Heat from a hair dryer was needed to get the vinyl to conform to the shape. There's still a few wrinkles but I think it looks good.
The top of the pod was just cut from thin sheet metal and covered with vinyl. The switches were attached and then the plate was screwd to the pod. Lastly, the whole unit was screwed to the door panel.