The most commonly used, and least hazardous etchant, in the chemical etching process is Ferric Chloride. Ferric Chloride is capable of etching stainless steel, brass, bronze, copper, aluminum, and nickel. It’s a versatile chemical that’s widely available and inexpensive. Most other metals can be etched when paired with the correct chemical. However, the chemistry required to etch metals such as titanium and gold is extremely hazardous and only a few companies have the capability to do so.
—Liam Dullughan, Laser2Etch