First of all, ART , your friggin crazy to be out there with those sharks...........i mean insane!
Kimoy, in this case we chose to go with a painted stand rather than spending the cash on powder coating. Powder coating is a better way to go , but the piaint we used should hold up exceptionally well, and saved Art some cash.
Mike,
I use MDF or HDF whenever possible. The material is extremely uniformn in thickness and lays true. Plywood is simply thin pieces of wood/veneer that are laminated to gether with opposing grain. Plywood of the same thickness is stronger than mdf , but is not as true in thickness and "flatness"....which , IMO, is very important for the surface of a tank stand(speacially acrylic). The strength of this stand is in the steel.not the substrate. Some might argue that mdf or hdf will swell when wet....which is true. This is why we laminate it in plastic laminate (formica type material).
Melamine is a particle board covered in a pressure thermo foil. The foil is extremely thin. The nice thing about it is IF the edges are sealed, the material is pretty water resistant, and can be used. It is just as flat and true as mdf, but not as strong/dense. For a larger aquarium, i would NOT use melamine. Also keep in mind that there are some melamines that are only "1 sided", and have a backer sheet on the opposite side. These sheets will warp under different humidity levels(NOT GOOD). Also , the way any of these substrates are stacked can be an issue. Ive seen H.D. racks that have plywood etc. stacked in such a way that the sheet is extremely cupped or warped (also not good).
I dont buy anything from H.D.
-greg-