I have long preferred water-based black stain for getting my furniture black, for a few reasons.
- First, I like the water-based cleanup process (just rinse with water).
- Second, I have always had problems with oil-based black stains, especially if I'm brushing them on, because oil based stains have a tendency to stick to the brush, and it's easy to remove stain from the work while trying to put it on. This is a problem peculiar to black stain, because with black stain, the goal is usually a completely black finish, whereas with other stains the goal is merely to tint the wood, or bring out the grain.
- Third, water-based finishes, including stains, dry much faster than oil-based finishes, and they tend to flow out more evenly, leaving a uniform finish on the work.
But water-borne clear coats are slightly less durable than oil-based clear coats. So I was considering using a regular oil-based polyurethane on my current project, a stand for a 180 gallon freshwater aquarium to be displayed in the front of Skipton's Unique Aquaria and Reptiles in Boston, Massachusetts. Then I saw a can of black Minwax Polyshades in my bin of finishes, and I decided to give it a try. In theory, Polyshades eliminates a step by combining the stain and the clear coat in one can. It's really just polyurethane with pigment in it, similar to oil-based paint. But since I had never used it before, I decided to give it a try.
My verdict: don't bother with Polyshades. Compared to water-borne black stain, Polyshades is difficult to apply evenly, and requires at least two coats to achieve a uniform black color. Water-based black requires only one coat, and it dries perfectly. I also found that Polyshades has the same brush application problem as oil-based black stain does: it's easy to pick the finish up off the wood when I'm trying to lay down more stain. And even though I spray a lot of my finishes, many people brush them on, so this is an annoying problem. Polyshades also tends to clump in corners, and it flows slowly, so after five minutes you'll have a smooth finish, but when you come back in ten minutes, sags and runs have developed. Of course, sags and runs are due to a too-thick coat of finish. But given how poorly the color sticks to the wood, Polyshades goads you into putting it on heavy, or else spending the time to apply three coats of the stuff.
I'd say that the best way to get a good, deep black on wood is to use a water-borne stain such as General's, and then follow that with either black-dyed water-borne poly, or an oil-based clear coat of your choice (I use polyurethane for the aquarium cabinets). Stay away from Ebony oil-based stains, and stay away from Polyshades.