I'm looking for advice on waterproofing a 3/4 plywood board that I'm using to build an aquarium stand. I'm mostly concerned about VOCs leaching into the aquarium, so I've avoided outdoor sealants that are typically used for decks. What products or methods would you recommend?
2 Answers
For light protection against spills, a water-based polyurethane or H2Olox could work well. If you really need to make it waterproof, consider using marine grade plywood combined with epoxy for the best results.
I built the bottom of my aquarium stand with a 2x6 frame and fiberglassed the entire area about ten years ago. It took a lot of effort, but it’s held up perfectly. The stand can hold up to 40 gallons before any leaks start showing. Here's a picture of the setup!
That stand looks amazing!

Is oil-based polyurethane a good option? Also, which is better for water protection: polyurethane or H2Olox?