Faux watercolor on metal

For years I've wanted to see if I could make a watercolor looking painting on metal, using alkyd paint. I tried it on this saw blade, and as far as the method goes, I'm quite pleased. The drawback in this instance are the little rust pits. The colored paint ran down into those, drawing the paint away from the rim of each one. The result is a lot of little white rings with a dark spot in the middle. There might be potential here, using a vibrating etch tool on a soft metal like aluminum. The pits would be much smaller, but would be in deliberate arrangements.
The surface is first washed with a mixture of varnish, turpentine, and boiled Linseed oil. The Linseed oil slows down the drying time; allowing the soft watercolor effects to happen.
Winter Trees
Closer View