How to do Metal Acid Etching

Etching metal with acid produces interesting artistic effects, with the finished piece displaying a varied and complicated topography, thanks to the acid's ability to eat away at metal. Metal acid etching is the process of fixing a design or picture on metal with heat-fused ink and submerging the metal in an acid bath.

The acid eats away at any exposed metal and leaves intact the metal covered by the ink. The result is a raised design and receded background, as the acid eats the background away. Acid etching is a fairly simple process that needs no special tools but that produces a very professional artistic piece.

  1. Select a sharp, black and white picture to etch on to the brass plate and print it with a laser printer set on its darkest, best-quality setting on glassy ink-jet paper.

  2. Clean the brass with alcohol to remove any coating or dirt and position the picture ink side down on the metal.

  3. Press and hold an iron on its hottest setting for approximately five minutes to the back of the picture to melt the ink of the picture on to the brass, then let it cool for about half an hour.

  4. Fill a plastic dish tub with hot water and submerge the brass in the water to soften the ink-jet paper, then peel it off--it comes off in strips and layers--until there is only a thin layer left on the metal. Remove the last of the paper residue by rubbing the face of the metal lightly with the fingers carefully so the ink left behind on the metal is not disturbed. Set the brass sheet on a paper towel until it's dry.

  5. Put on a pair of protective gloves and a pair of protective goggles or glasses to protect the eyes.

  6. Empty the plastic tub and dry it. Use the directions on the container of ferric chloride to create the acid solution, then submerge the brass sheet in the acid bath and let the acid eat away at any metal not protected by ink. Leaving the metal in the acid for 12 hours yields an etch depth of approximately 1/20 inch, a full 24 hours twice that.

  7. Remove the metal from the acid bath with tongs and hold under clear running water to rinse off the acid. Rub gently with a soft cloth to remove any discoloration produced by the chemicals in the acid.