Designing Pottery: Executing the Design

I've photographed several pots from start to finish, which is the best way to see how a design is executed. Click on the photo if you'd like to see the process. The information below is mostly technical. I hope it's useful to people involved in making pottery.

The glazes at Mudville are mixed in the studio and have come from a life-time of glaze testing, an on-going endeavor. One of the most useful glazes we have is a cone 6 semi-matte glaze that has been consistently reliable over the years. The recipe for it is:

Cornwall Stone 20% Custer Feldspar 40% Zinc Oxide 11% EPK 8% Whiting 15% Kentucky Ball Clay 6% Gerstley Borate 5%

You'll notice that this adds up to 105% instead of 100% but we pretend the total is 100 when adding coloring oxides percentages. Without added oxides, this glaze is a greyish white on brown stonewares, white on porcelain and lighter clays. The unfired surface of this glaze is not dusty, so it's perfect for painting with underglazes. Despite their name, I have used underglazes on top of glazes for many years with excellent success. For the most part, I use underglazes on top of a glaze on pot exteriors, rarely on interiors where the underglazes will come in contact with food. The underglazes do penetrate the glaze and appear to act like any other colorant but I haven't tested them for heavy metal release.

The glaze I use the most when I'm painting on tan and brown stonewares is the above glaze with 5% light tone powdered rutile added. The rutile makes the glaze more opaque and adds an antique parchment quality. Greater quantities of rutile also make handsome glazes. Other lovely glazes can be obtained with additions of copper, cobalt, and iron alone, in combination and in combination with rutile. Our studio black, a rich satin matte, uses 12% powdered manganese dioxide and 8% red iron oxide. I would think twice about using a glaze this heavily laden with oxides on the interior of an object of daily use, say a mug or a bowl, but otherwise it is a versatile and beautiful glaze.

When I first started potting, reliable high-fire red glazes for oxidation kilns were non-existant. That has been changed substantially by the micro-encapsulated glazes now widely available. Bright reds, as well as lime greens, pinks, lemon yellows, almost any color imaginable is out there, though at substantial cost. These commercial glazes, by Spectrum and others, are vivid and brilliant and certainly have uses in most potters' palettes. They are cold glazes though, with little variation and tend to produce ware that looks more like it came from a variety store than from a local potter. My favorite use for these glazes is small areas, in line or geometric designs, surrounded by the warmth of in-house studio glazes. Their enamel-like quality can also look great in stained glass sort of designs.

I primarily use Amaco underglazes as well as some English underglazes and the newer Spectrum underglazes. I mostly use the Amaco pan sets, sprinkling in water to soften the underglazes before I use them. For a while, I used expensive sable brushes for painting but am now primarily using the cheaper synthetic taklon brushes. Underglazes are hard on brushes and the sable seem to lose their point before the taklon. Most of the underglaze colors are mixable, though you often can't see what you're going to get.

For latex resist, I use temporary watercolor mask, usually Windsor and Newton. Latex resist destroys brushes, so I buy the cheapest plastic kiddie brushes from crafts stores, which cost about $.10 each. I use them once and toss them out. We don't have latex available for the Mudville students because I'm afraid all the studio brushes will get wrecked. I also use masking tape for resist when blocking out larger areas and bands around pots. Students use stickers, like hearts and dots, then peel them off and fill in with a second glaze application. I don't use latex resist on porcelain if I will be painting with underglazes. I find that the resist leaves behind a surface residue that blocks the absorption of some of the underglaze. This could be burned away by re-bisqueing but that's another step and more time. If I'm doing lines or other small areas, I often glaze the entire piece, then with a pointed tool, scrape back to the clay surface. Then I use damp Q-tips to clean up the clay before filling in the line or area with a contrasting glaze.

Wax resist is another way to isolate one glaze from another. I use wax resist when I've painted on top of a glaze and plan to dip the pot in another glaze. Latex is not suitable here because the latex will take off some of the underglaze color when it is removed the pot. Wax resist is easy to use over glazes except when you are using glazes with a dusty surface. I've heard of people spraying pots with spray starch (used in ironing clothes) to stabilize dusty glaze surfaces but my solution is to avoid glazes that are dusty.

I use a ceramic easel that I got more than 20 years ago, made by a company that became part of Scott Creek Pottery, the people who make excellent extruders. I don't believe that the easels are made anymore, a shame because the design is an excellent one. It would be very difficult for me to make some of the pots I make without the easel. It gives me a way to rest my hand away from the pot surface, helping to prevent smearing. Also, by supporting the pot, the easel makes work a lot less tiring and you don't have to worry about dropping the pot. A turntable raised to the right level (I use books) can also be very helpful and a substitute for an easel. Here are pictures and dimensions of the easel for anyone who wants to try to make his own.