Step 0: Problem

This week I built a composite duct to replace the kink prone dust
collection hose on the shop bot. Hopefully this will cause the
dust collection system to get clogged less often.

Step 1: Form

First, I built a laser cut cardboard skeleton for the mold.

Step 2: Shrink wrap

Next, I tried to shrink wrap the carboard skeleton with the boat
wrap. I used the double sided carpet tape to adhere the wrap to
itself. Unfortunately, the surface formed by the wrap after heat
shrinking was very wavy.

Step 3: Tape wrap

To get a better surface, I removed the boat wrap and wrapped the
form with tape.

Step 4: Lay up

I used strips of linen cloth and epoxy resin for the lay up.
The thickness ranges from two to three plies.

After the epoxy cured, I filled the duct with water and then
removed the soggy tape and cardboard. This worked pretty well.
Then, a quick trim on the bandsaw cleaned up the edges nicely.

Over and out.