Clay

  • You're in the middle of a really special piece when you get a phone call that your daughter's car broke down, two hours away, or you have this really amazing sculpture started, but you're not quite sure on the ending... now what do you do?

    This type of thing happens to us all. The question is, how can you keep these pieces soft enough to finish, even if it's at a much later date?

    Well lucky for you, it's time to learn how to build a "Damp Box."

  • Even as a professional potter, there are things I struggle with. Making multiples is one of those things. I dread it when a customer orders a "set" of mugs, bowls etc... You see, I'm a bit of a perfectionist and it is very difficult for me to accept anything less than perfect.

    Working with a mentor a while back, she gave me some good suggestions. I was too stubborn to put those suggestions into practice at first, so I continued to struggle.  Finally, while sitting at the wheel one day, I decided to throw just for fun. I had a blast!

    Surprisingly, a lot of the pieces were similar! More importantly though, it reminded me that clay is supposed to be fun, and I was wasting fun on worry. It was time to buckle down, and try some of those suggestions, before I gave up all together.

    That being said, I've learned how to appreciate the fact that I'm not perfect. There are ways around achieving "exact",  and accepting "close" is getting easier.

    Here are a few of the tips I learned:

  • Potters use clay in many forms. We have a huge selection of pugged clay and slip, but sometimes commercially available clays don't offer features that a potter may be looking for such as being locally sourced, or a certain plasticity, glaze fit, or strength. Mixing your own clay body takes a little experimentation and some trial and error, but has the potential to yield high rewards.

    Clay Basics – Local Clay

    Pure clay is also known as hydrous aluminum silicate (Al2O3-2SiO2-2H2O) and makes up nearly 75% of the Earth's crust. Because it is so common, the most basic clays can usually be found within walking distance of your studio. The easiest places to find clay are by the sides of rivers and streams (look in the outside bends where the water has eroded the topsoil) or 5 feet below the surface of the ground (especially under soil that is sticky).

    Once you hit clay, you can do some basic tests to determine if it is usable. First: try to roll a coil. The more plastic (flexible) the clay, the thinner the coil. Second: rub the clay between your fingers. If it feels smooth and round, it will throw easily. If it feels sharp and gritty it will be more difficult (but may have some desirable properties when fired).

    After you dig up your clay, cut it into 1-2 inch pieces and put it in a bucket of water for 3 days (or until the clay is fully slaked). Mix the clay and then pass it through a 30-50 mesh screen to remove unwanted pebbles, sand, and other materials. Then pass it through an 80-100 mesh screen to remove finer grit. After drying to the desired wetness, the clay will be ready to use.

    You will need to experiment in the kiln to find the right bisque and maturation temperatures, as well as shrinkage and glaze fit, and you will most likely have to add additional clay and chemicals to achieve the desired final properties.

    Here are some basic troubleshooting tips to help: if your wet clay doesn't hold its form enough, add ball clay. If your clay is too plastic, or too sticky to work with, add fireclay. If your clay is too dark, matures at too low a temperature, is brittle when fired or shrinks too much, add kaolin.

    Below is a tried and true earthenware recipe for use with local clays.

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