View Larger Image While you may expect the water-etching spray to undercut the wax (like sandblasting undercuts a stencil) the pattern remains crisply defined; even thin, fine lines survive undamaged.

December 24, 2007

Technique of the Week: Water Etching

by Roger Graham | Read Comments (2)

Last year while traveling, I bought a porcelain pot with a delicate raised pattern on the outside, carved with infinite patience, or so I thought. “Not at all,” the potter informed me, “It’s water etching.” The process is so quick and the unprotected clay washes away so fast, that it’s possible to etch to a depth of a millimeter or more in less than a minute and follow a wax outline precisely.

I use the ordinary gravity-feed spray gun used for applying glazes, set to about 100 psi instead of the usual 40. It was adjusted for a fine wide-spread spray and held about 2 inches from the pot. But you could use a garden hose adjusted to a fine mist. Truly, it’s as easy as that. The whole procedure takes only a minute or two and the lower edge of the inverted pot, which would soften first, needs only a gentle blotting with a soft sponge.

Step 1
Produce work for this process using smooth, fine-grained clay. Allow it to dry to the bone-dry stage.

Step 2
Paint a design on the pot using wax resist and a fine brush. This simple plant motif was painted on, using wax emulsion heavily loaded with dye so the narrow brushstrokes were easy to see (figure 1).

Step 3
Invert the pot and suspend it on a pedestal or chuck. The rim of the pot needs to overhang the pedestal so water can drip into a catch basin.

Step 4
Apply a fine spray of water. The water will wash away clay that is not protected by the wax. Gently blot away water droplets from the rim with a soft sponge (figure 2) to prevent the rim from disintegrating. Warm air from a hair dryer speeds up the return to crisp dryness.

Step 5
When the pot is dry again, or nearly dry, you can pick it up and refine the details if necessary. These details are easily added by hand with a pointed tool after the water-etched pattern has dried. If you’re not satisfied with an outline of part of your design, just scrape it away. It’s easy to make minor repairs, just don’t get carried away.

For Further Information
See a term you weren’t quite sure of? Then visit the Ceramic Arts Daily Glossary. To see more of Roger Graham's work, visit his website at http://members.optusnet.com.au/~rogergraham.