Set up the desired diameter PVC pipe on two pipe stands. The pipe will have to be one foot longer than the finished length of tube that you need. Place the stands three inches from the ends of the pipe. Lay cardboard on the ground underneath the PVC pipe to catch any excess resin.
Apply three thick coats of mold release wax to the entire surface of the PVC pipe, using the foam applicator that comes with the wax. Let the wax dry and buff to a shine with clean rags.
Wrap the entire PVC pipe with a layer of fiberglass mat and cut it with scissors so there is no overlap at the seam. Using the first layer for a pattern, cut the desired amount of layers for your tube. The more layers, the thicker the tube will be.
Put on a respirator and add catalyst to a small bucket of fiberglass resin, following the containers recommendations. Using a stir stick to mix the catalyst into the resin.
Wet the surface of the PVC pipe with the resin mixture, using a felt roller. Apply the first layer of fiberglass mat and use the felt roller to saturate it with resin. When the entire layer is wet with resin, use an air roller to remove all the trapped air bubbles. Repeat this process for each layer of mat until all of the mat is on the PVC pipe.
When the fiberglass starts to harden but is still soft, mark the tube to the length you want with a sharpie marker. Cut the ends of the pipe with a razor knife and remove the scrap fiberglass. Let the fiberglass tube harden.
Insert a metal scraper in between the PVC pipe and the fiberglass and slowly work it around the entire circumference of the pipe until the fiberglass releases from the PVC. Do this to both ends of the tube and then use a rubber mallet to pound the tube off of the PVC. If you don't let the fiberglass completely harden this will damage the edge of the tube.
Sand the tube smooth using 100 grit sandpaper.