The WD40 displaces the water absorbed into the composite (around 1% over prolonged exposure, according to this research: https://pdfs.semanticscholar.org/aae5/cc999bf7184d7bba7cc7d6f44979c4c9afa9.pdf ) Waxes do little to seal the surface effectively and from my experimentation with a number of synthetic wax/sealer treatments, do not correct the water mark already created (also, lots of complex chemicals in these, too, so not necessarily any more environmentally friendly than WD40). Thanks. I can understand how WD-40 displaces water in the material, and it is very good at that. Does the milkiness disappear as soon as it's applied or is there a noticeable delay? But once that has been achieved I don't understand why it would be better than a hydrophobic wax. They should have the same effect on subsequent water penetration but I'd expect the wax to hang around longer. Have they ever been compared after the initial application of WD-40? Jonathan