I never realized how hard it is to find a 3 1/2 inch pipe so I can french in the Caddi tail light. So I decided to make my own. I took a piece of 3 inch pvc pipe which just so happened to be 3 1/2 inches on the outside diameter. I greased up the pipe, so the fiberglass wouldn't stick to it, then I used fiberglass cloth and wrapped it up. I used cloth because it has a smooth finish. Then I wrapped it in a couple layers of fiberglass mat for more strength.
I'm also glassing a piece of wood that I'll use for the tail light to actually bolt to. This is a picture while I was removing it from the pvc tube. I know, it looks like a mess and probably doesn't make sense to you, but once it's finished you'll understand.