Monday, November 26, 2012

3 for the price of one HINT OF THE WEEK

HINT FOR THE WEEK OF NOVEMBER 26th; Wax resist where you don’t want it! (Inspired by the Big Ceramic Store).

“This happens to every potter, new or experienced. You accidentally get a spot of wax resist on your bisqued piece. No matter how small, this spot will resist the glaze during firing leaving you with an unsightly blemish.

The only sure way to truly get rid of wax is to vaporize it with temperature high enough to burn the wax off. No amount of sanding will get it off, as the wax is absorbed into the bisque.”

The most common method is to burn it off by re-firing it in the bisque. You may also burn it off with a torch or heat gun.

If you don’t have time to re-bisque it you can try to put it in the microwave on high for five minutes. Make sure you let it cool before you remove it from the microwave as your piece will be extremely hot!Some also say you can use a solvent like Alcohol to dissolve or remove the wax

At the Helena Clay Arts Guild we require that all green ware put on the shelves to be dry. We only fire dry pots. You can check if a pot is dry by feeling it, and one method is to hold the pot against your cheek. If it feels cold or damp, it still has moisture in it and it needs to dry more. Often pots are thicker on the bottom and they also dry slower here, so feel the bottom not just the side of the pot. Since our building temperatures drop when no one is in the building, the pots can feel cold because they are cold and it may not be moisture. So when you feel the pot to see if it is cold, hold the pot to your cheek for a few minutes. If the pot feels warms up or feels warm within a minute or two it is most probably dry.

We can preheat the electric kiln for several hours, which keeps the kiln below 180°F (water boils at 212°F) for the “preheat” period and will evaporate moisture in the clay. However, this only works for small amounts of moisture and if your pots are real moist it may take 8-10 hours of “pre-heat” and that makes it more expensive for us to fire. We try not to preheat at all, but will go up to 3 hours for really large or thick pieces, if we have to. If items in the bisque or any kiln have moisture in the clay and it is not evaporated out the moisture turns to steam and blows the piece up. It could also damage other pieces in the kiln. You will still pay for your piece and any that it may damage, so make sure it is dry before you put it on the shelf. Don’t put it on the shelf thinking it’ll dry before they fire it, because we’ve had plenty that have blown up because there was still moisture in the clay. If we think it is wet we won’t fire it and we may return it to your tub or studio.

HINT FOR THE WEEK OF NOVEMBER 12th: A unique way to make a mold is to use hard foam insulation board from Home Depot, Lowes, Power Townsend, etc. (the stuff that comes in 4'x8' sheets, usually 1" thick, and is often pink). You can use a utility knife to cut out shapes to use as slump molds. The author, from Big Ceramic Store was going to use this method to make some square plates.

Another, great way to make plates, trays, etc. is with a block of wood (square or rectangular.) Cut a piece of clay larger than the wood. Put the clay on a large piece of foam. Take your block of wood and press down in the center of the clay. The sides will come up and make nice rims. This looks really great if you impress the rim with stamps before pressing in the center (From the Big Ceramic Store).

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