How should I stain a stock with iron nitrate?
First sand the stock progressively with 150, 220, and 320 grit sandpaper, wetting and drying between grits. Apply iron nitrate with a rag so the surface is a little wet, let it dry for about an hour, then heat it with a heat gun on high, keeping the gun moving so you don't scorch the wood, until the color shifts dramatically from a grayish green to a richer color. A second coat and reheating can deepen the color further, and a final coat of finish oil, rubbed in with fine abrasive pads like scotch brite, brings out the full richness of the stain.