Creating a Kaleidoscopic Surface with Underglazes and Water Etching How to layer underglazes using plastic mesh in which clementines are often packaged, to create amazing, multi-colored surfaces Angelo di Petta

It never ceases to amaze me that even after the many (many) years I've been with Ceramic Art Network, I am still coming across techniques that are completely new to me. Case in point, today's excerpt from his article in  Pottery Making Illustrated. 

In this post, Angelo di Petta demonstrates how he uses layered underglazes and the plastic mesh in which clementines are often packaged to create amazing, multi-colored surfaces. Don't miss this one! - Jennifer Poellot Harnetty, editor

PS. To learn about Angelo’s slip-casting process, be sure to check out the July/August 2022 issue of Pottery Making Illustrated!

Designing the Surface

I have used the etching process for many years, but what inspired this particular series was the plastic netting that I found on cartons of clementines. It seemed like the perfect material—simple cut-out pattern, thin, flexible, reusable, and free. It worked very well with the layering of colors and patterns. My goal was to create as much visual activity as possible on a limited surface.

Etching the Surface

The first step to creating the surface is to layer many colors of underglazes on to the greenware piece. I start with a black layer to coat the entire exterior of the form (1). Then, I use blue, turquoise, red, yellow, and orange layers in random patterns. I use masking tape and stencils to create these shapes (2). The lighter colors are used last (3). I apply one coat of each color of underglaze. I prefer the consistency of the underglaze to be thicker rather than flowing and use a soft ¾- or 1-inch brush to apply it. This gives me a smooth surface. I allow the layers to dry between coats. 

The next step is to create the relief patterns. This is done by etching, essentially wiping away to reveal the layers of colors. I use a masking material, in this case the plastic netting that comes with boxes of clementines. The netting is stretched over the form (see 4), taking care not apply too much pressure that could break the greenware. I then use a damp sponge to gently wipe away the underglaze layers until the black layer or the base clay is revealed (4). The neat part of this process is the control one has as to how much to etch, or how little.

Finishing the Surface

When I feel the etching is complete, I apply 3 or 4 coats of red terra sigillata to seal the bottom. The piece is then ready to be bisque fired to cone 04 (5).

After the bisque firing, I apply a commercial liner glaze to the interior (6) and a clear glaze over the etched exterior (7). The glaze firing is taken up to cone 06. 

Angelo di Petta’s home and studio are located in the rolling countryside near Millbrook, Ontario, Canada. He graduated from the Ontario College of Art (now OCAD University), and for 46 years has shared his knowledge of ceramics, model and mold making, and design through teaching, lectures, mentorships, and workshops. To see more of Angelo’s work, visit dipetta.com and @angelodipettaceramics on Instagram.

**First published in 2022.