In this YouTube video, Eric Strebel looks at one way of creating a hermetically sealed electrical connection by using hermetic terminal seals. This type of connection is helpful when looking to place electrical connections inside a pressure tank. A hermetic terminal seal allows an electrical connection without any of the pieces touching moisture.
Ideally, a pass through point needs to be chosen, such as a nut that can be drilled through, through which other components are to go, and then correctly sealed. Remove and clean the pass through nut thoroughly of all build-up materials. Machine out two square shapes in the back of the nut. Clean and scrape the surfaces so that the epoxy will take proper hold of them.
Cut down any sides or sections that aren’t needed. Use the appropriate length of copper strips and solder them to the ends of the connection points.
Make the seal that will prevent the resin from escaping the parts by cutting the appropriate shape out of acrylic with holes for the copper strips to come through. Cut the copper strips to the same length and pre-tin them.
Place the female end of the electrical connector through the passthrough nut. Place the seal down on the outside of the connector and screw the rest of the pieces into place. Solder the male end to the exiting points of the copper strips. Slide the pieces down. Glue the acrylic down to the metal. Pour resin down through the hole from the other side. Finally, pressure cast the entire assembly.