Safer than using acid in metal etching. Ferric chloride etches copper, brass, stainless steel and some aluminium in printing plates, decorative damascus knife blades. The depth of etch depends on the freshness and concentration of the solution and duration submerged. Resist are molten beeswax, bitumen, paint or permanent marker. During the etching occasional brushing of the design exposes the metal further to the chemical reaction. In knife making ferric chloride etches the metal to reveal its permanent beautiful pattern. Scale modellers etch metals as decorative designs or to create rustic effects.
Also used in Raku firing as a colorant. Dip T22 slipcast fired ceramic bisquitwares in ferric chloride solution in single or double dipping. Wrap tightly in aluminium foil and raku fire. The fired color is awesome from light to intense ranging from yellow, orange or maroon. No two firing colors are the same as concentration of ferric chloride differ in the absorption.
Wood staining with brush on ferric chloride solution will darken wood. Apply on unpainted or unwaxed surface for absorbtion. Trial test wood pieces.
As in handling any chemicals do take the necessary precautions of eye goggle and hand gloves etc. Ferric chloride is not flammable as waterbased.