I use a process incorporating lacquer and wax on my Fender-style exposed-pole pickups. Potting the bobbins in Lacquer insulates the magnetic poles from the winds, this way a short is prevented if the coating on the winds is thin or starts to corrode. Once the pickup is completed, it is dipped in wax to prevent microphonics.
lacquer-potting pickup bobbins
Lacquer-potting bobbins is very simple. Once the top, bottom, and polepieces are assembled, you can dip the bobbin in brushing lacquer from the hardware store and hang it to dry for 24 hours. Once drying is complete you can wind it just like a normal pickup.