Every bench I've built before including my current one that has steel shelving for legs, has had a wood top. My current top was made from two solid core doors screwed together. After getting the bench to that stage I take the measurements to my local air conditioning repair place and have them make from the thickest sheet metal they have, a steel top that is bent to hang over all four sides. I first screw on the side's edges a flat piece of perforated metal. Then I glue the sheet metal top on and pop rivet the bent sides to the perforated metal. Strong as an ox and not a bit of any liquid gets to the wood. I keep the top in shape by using a WD-40 dampened rag for a wipe down. No rust and no fuss. Smithy.