Lightheads
I design and make standardized lightheads for diving that house LEDs from 10w to 150w.   They are designed to dissipate heat away from the LEDs and drivers and also withstand depths of 300+ feet.  I machine the heads from 6061 Aluminum pipe and then anodize them in sulfuric acid bath.  I cut out the acrylic front and back lenses on the CNC, then finish them on the lathe.  I make the handles from PVC – I heat it in an oven until it is rubbery and then press it flat.  I machine the flat stock on the CNC and then reheat it to shape the handles in a custom made jig.  The fittings are epoxied in place and after everything is assembled I depth test in a pressure chamber I built from a discarded scuba tank.