Routed Port Flares
The easiest way to make a port flare is to use a routerAn economical, good looking flare can be made using a routed rollover at the port exit. The flare radius achievable with this method depends on how large a rollover bit you can find for your router. In Australia, the best you'll find is 13mm for a small router and 30mm for a large, table mounted router
Cross-section of completed port with routed flare
Initial cutoutMount your router onto a circle cutting jig. I made my own, but your router probably came with a simple one. You could also purchase a Jasper jig. From the back of the mounting panel, plunge route a cylindrical cut the exact diameter of the port. It helps to practice on a piece of scrap to get the correct diameter. Cut the depth so that there is enough material left for the flare, plus a couple of mm
Flip the panel over, and from the other side, route a smaller hole right through. Make this 10mm smaller diameter than the port's internal diameter.
Mounting the pipe Cut the PVC pipe at 90 degrees. A simple way to get 90 degrees is to roll a piece of cardboard around the pipe. When the edges of the cardboard line up, mark around the pipe with a pen. A normal hand saw is fine for cutting PVC, and wanders less than a hacksaw
Glue the PVC pipe into position and leave till dry. If you are using a double thickness front panel, there will be enough surface area to just use PVA glue For more strength, fast setting epoxy can be used