Big Ceramic Store Blog

Monthly Archives: March 2015

  • When's the last time you did throwing exercises? They are great for warming up after a period without throwing, for improving your skills to the next level, and for getting ideas when you are out of them. Here are some great exercises.

    Timed Throwing

    Timed throwing is especially good when you are in the habit of obsessing over every piece. Weigh out 10 equally sized balls of clay. They should be an amount you can rather easily throw (don't use more than you can easily center).

    Choose a shape (cylinder, bowl, etc.) Get a timer and set it for 3 minutes. Start the timer. Center and throw the first ball of clay. Stop when 3 minutes is up, cut off the pot, and rest for a minute. Start the timer and repeat 10 times.

    At least every few pots, you should take your cutoff wire, run it beneath the piece half way, then pull right up through the center of the pot, cutting it in half. Observe where your walls are thick and thin.

    Repeated Throwing

    Even if you don't do timed throwing, it is very useful to take equal amounts of clay and try to make multiple pieces exactly the same. You will need this skill for doing sets (ie. dinnerware), but it is also useful for developing technique. Don't try to do it without a scale... If you're like most people, you'll find that you are not very good at eyeballing equal weights!

    In Japan, apprentices throw thousands of copies of the same shape, and are not allowed to progress to a new shape until they have mastered that one. One of their early shapes is a production sake bottle, where it is important for the size to be right so the bottler isn't giving away too much liquor nor cheating the buyer.

    Throwing on a Theme

    This is good for exercising your creative juices and learning good design. Starting with the same amount of clay, make similar items but find a way to differentiate them slightly. Most professional potters work this way, exploring a shape until they have to push it to its limits.

    Follow Along with a Book

    For example, "Wheel Thrown Ceramics" by Don Davis has both projects and photos of thrown pieces. A great book for the intermediate potter, it focuses on thrown and altered forms, and techniques for capturing the spontaneous fluidity of clay. Follow along, first duplicating each form, then expanding in it. Again, it is best to do several of the same form before moving on to the next.

    We sell a variety of throwing books. If you find yourself having difficulty duplicating a shape, you may need more demonstration than a book can give. In this case, a good set of DVDs on throwing might be more the way to go.

    You may try these exercises knowing that you won't keep any of the pieces. Just cut them off the wheel, re-wedge the clay, and use it again. Some people find that knowing they won't keep the piece allows them to be more experimental and take more risks.

    So next time you're stuck in a rut, or not sure what to make, do some exercises and you'll see how much better your work gets!

  • If you've never used a slab roller, it can seem daunting. But it's not as hard as it looks. Follow along with the steps below and the video above and get rolling!

    How to Use a Slab Roller

    Step 1: Wedge clay.

    Step 2: Clear the surface of the slab roller, remove one spacer from under the rolling surface and lay canvas under and on top of your wedged clay.

    Step 3: Begin rolling. Don't try to roll faster than necessary and if the roller jams, do not force it; back it up and figure out what it is catching on (your clay may be too thick).

    Step 4: Flip your slab over, rotate it 90 degrees and reinsert the spacer under the rolling surface.

    Step 5: Roll again.

    Step 6: Uncover, smooth with a rib and transfer to a board.

  • Here is a common scenario. A potter sees a piece with a glaze they really like. They get the recipe, mix up a batch, and are disappointed with the results. Their glaze looks nothing like the one they originally saw. If this has happened to you, you know the frustration.

    This happens for a few reasons, but most of all by what has influence over the glaze itself during firing.

    A Glaze Is Affected By:

    • Final temperature. Even if fired to the same Cone, the temperature may vary from one part of the kiln to another, or two people might interpret the bending of the Cones differently.
    • Rate of change in temperature, particularly cooling rate. This is a main reason why glazes look different when fired on a whole piece than when fired in a test kiln, because the smaller test kilns usually cool faster.
    • Clay bodies. Color as well as the materials in the clay body. For example, iron in a clay will often cause spotting through the glaze, or will act as a flux causing glazes to melt earlier).
    • The thickness or thinness of the application or the method of application (sprayed, dipped, or brushed).
    • Variations in materials (Glaze materials are taken from the earth, and their compositions are not pure. There is always some variation from batch to batch, and sometimes this variation is enough to affect the glaze in a substantial way).
    • Atmosphere: The amount of oxygen present or not present (reduction).
    • The presence of other glazes nearby.
    • Particle size differences. If a material is available in 200 mesh and 325 mesh, these will melt differently and give different effects.
    • Mixing and screening. How well the materials are mixed and to what mesh they are screened will effect the final result.
    • Venting. Whether and how much a kiln is vented can affect the final firing.

    As you can see, there are many factors, so it is not surprising that it is hard to replicate a glaze.

  • This post was made by Lora Olivieri of Piece of Mind Pottery. If you’re interested in posting on our blog, shoot us an email!

    When it comes to selecting a clay body, the possibilities seem endless. There are so many different formulations and variations, colors, textures, workability, throwability (is that a word?). It can get confusing to select the perfect one. Which is why most potters I know, including myself, don’t settle on just one.

    I use both earthenware and stoneware in my work. I gravitate towards white stoneware (Laguna WS-4 is my favorite) but I also dabble in brown and black stoneware and also earthenware like Laguna EM-210 when the project warrants low-fire glazes and underglazes.

    So what’s the difference between earthenware and stoneware? Here’s a quick breakdown:

    Earthenware:

    • Low-fire: cone 06-3 (1850-2135 degrees).
    • Slightly porous, even when fired to maturity (water will soak into it if not glazed or sealed).
    • Low-shrinkage from wet to fired states.
    • Great for planters, oven steamers/garlic roasters, kids projects/art class and decorative items.
    • Not so great for dishware as it is not as sturdy as stoneware or porcelain and is prone to chipping and staining.

    Stoneware:

    • Mid-High fire: cone 4-10 (2160-2372 degrees).
    • Non-porous when fully vitrified (fired to maturity temperature recommended by clay company).
    • Widely used for dishware and functional items as well as sculpture and decorative pieces.
    • Range of shrinkage depending on specific clay composition, but your piece WILL get smaller when you fire it.

    • julie Aitken | #

      can i apply an earthen ware glaze to a stone ware clay?

    • Bethan Naisby | #

      I am making some plant pots, they will be outside through the winter. Should I use stoneware/earthenware?

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