Sometimes I feel like I was born in the wrong era because I just love old things: antiques, weathered old buildings, vintage clothing. If you can relate, then you’ll love today’s feature because we’re going to show you how to create a crackled, craggy texture on your pottery. The late Canadian potter, Robin Hopper, explains how some heating, some stretching and a little sodium silicate on pottery can transform a freshly thrown pot into what looks like a weathered antique. –Jennifer Poellot Harnetty, editor.
Creating a Crackled Texture is Easy with Sodium Silicate on Pottery
Brushing the surface of a thrown pot with sodium silicate, quick-drying the surface with a heat gun or blowtorch until the surface no longer is tacky, then expanding the form from inside can give a piece of pottery an aura of instant antiquity.
The sodium silicate is a thick liquid salt solution that forms a thin skin that, with applied heat, quickly hardens on the surface, encasing the soft and therefore, still malleable, clay cylinder beneath. Normally used as a deflocculant for casting slips, in this use it is quickly dried to the touch with some heat from a blowtorch. At this point, it is like a candy apple, crunchy on the outside and soft inside.
When the form is then expanded with pressure from inside, the skin surface cracks enlarge in size depending on the amount of pressure and expansion. The residual sodium silicate gives a slightly glazed surface like a thin salt-glaze.
Variants that will also work are a thick salt (sodium chloride) solution or sugar pancake syrup (Aunt Jemima’s, for example) solution (which produces great caramel smells from the caramelizing sugar during the firing!). The essence of the process is in the speed with which it is done, as the coating needs to stay hard and not absorb moisture from the soft clay beneath.
Robin Hopper's Making Marks covers everything you need to know about enriching the ceramic surface. From concepts and ideas to research and processes, his book shows you the great variety of marks you can make at any stage of the ceramic process. Whether you want to carve or add clay, brush on slips or dip glazes, raku or pit fire—you'll discover how to choose and use the technique you need for your pots!
Book: $44.97 | PDF: $39.97
The late Robin Hopper and his wife Judi Dyelle owned and operated Chosin Pottery in Victoria, British Columbia, Canada. Visit www.chosinpottery.ca to see images of their work and learn more about Chosin Pottery.