Am at the point of after removing my less that adequate darkroom sink, have replaced it all with an 8 foot exterior plywood base and shelves and atop it a 2x8 foot sink. Getting ready to paint the interior of the plywood sink. Over the years have constructed and used 2 plywood sinks for 10+ years each. One was marine and the other exterior plywood but both covered only with many coats (top a base coat) of exterior paint and never had a problem. Epoxy paint seems to be the choice of many... adequate ventilation obviously a must. Will be installing an exit ventilation fan in the darkroom but not till the spring so epoxy paint not an option till several months from now.

Anyways one of my former students built a darkroom. Plywood sink. Base coat of paint. 2 or 3 coats of exterior paint. And then he uses car wax to coat the sink a few times per year. Told me takes only 10 minutes each time. He told me water beads off the sink like off a waxed car. He and his wife use the sink for various other things and he told me anything and everything always just beads and washes away!!

Anybody else has tried using coats of car wax? Sounds like a simple practical fix to me verses using epoxy paint in an unventilated room.