26.How to pour a mold

Creating your own greenware saves money and gives added satisfaction.Here Gertrude Engel shows every step from pouring to finish.

Several molds, a gallon of slip(liquefied clay), a kitchen table to work on, a wooden mixing spoon and a crock or glass jar to pour from a single wood modeling tool or an orange stick – and you are ready to turn out lovely ceramic bodies that, when finished, you can sell or give as presents.

The above material will make the greenware that you can paint or glaze for a finished product.Today, manufactures make varied and beautiful glazes that are easy to apply, and everyone can create ceramic pieces of fine appearance with little experience.

One thing to keep in mind when you use a brand-new mold is that the first couple of pieces to come out of the mold seldom are good.After that, the mold will be broken-in and turn out good ware.

pottery wheels

pottery wheels

Above is three-piece mold that consists of two sides and bottom.When you buy a mold from a commercial house each piece has keys or notches that fit together correctly, so you can't vary the use.Molds don't come with rubber bands to hold them together during the molding process, so make your own; best bands are made from a tire inner tube.

Slide rubber band over width, another over length.Mold must be held together tightly, so add more bands if needed.Insufficient tightness will re­sult in mess since slip will seep through crevice.

pottery wheels

Left, finished piece is a beauty, and a credit to your work.After it was fired to its proper cone number, kiln was shut off; when thoroughly cooled, door was left ajar until most hot air and gases escaped and then opened completely.Do not remove ware until quite cool, to protect glaze.

Always spread newspapers down where you work for easy clean-up afterward.Once you open can of slip, which can be bought in one-gallon size, do not keep slip in can for longer than it takes to mix slip; otherwise, the slip will become tinged with rust stains.Keep slip in glass, ceramic or porcelain-lined container.Here, slip was poured into glass jar and mixed evenly and slowly with wooden spoon for about ten minutes, to a creamy liquid.Mixing too hard will create air bubbles.

pottery wheels

pottery wheels

pottery wheels

Pour slowly, evenly into the mold.Pour a whole mold without stopping or lines will appear in the piece you are casting.Pour slowly to let all air escape from the mold and insure fine detail work.

Time how long slip is kept in mold.Piece of this size usually needs to stand about 15 minutes for the first casting: add 2 minutes to time for each additional piece cast during continuous use, and don't cast more than three or four at any one time or mold will get too wet and not operate properly.Plaster absorbs water from slip, allow­ing clay to coat mold: if slip settles, add more.

Now pour out slip, back into container, and pour slowly to prevent piece from collapsing.Allow it to drain as you keep hand steadied on container.

Keep mold upside down and let it drain on news­paper; rest it on two sticks.Keap it there until slip (now clay) loses its shine and looks dull.

pottery wheels

Turn mold over and with soft wooden modeling tool release the spare at top of mold.This is waste clay that is always at top of mold; discard it.

This is how mold looks with spare pulled off.Al­ways use extreme care in working with tools on a mold since it's easy to gouge out bit of plaster.

Lift mold oft the base and place it on a plaster bat.If piece you're casting is ready to come out of mold, the base will be released very easily.

Now separate the two sides, one at a time.Again, if the sides release easily the piece is ready to come out.If rushed, piece may collapse on bat.

pottery wheels

pottery wheels

Vase is placed on a bat, with three-piece mold alongside.Trim off excess clay where spare was, and set piece aside to dry, keeping it on bat.

pottery wheels

pottery wheels

pottery wheels

When completely dry, a matter of days, begin the finishing.Use composition sponge or a fettling knife to smooth it off, obliterate imperfections.

pottery wheels

To smooth down the neck of vase, use a piece of grit cloth nailed down on a plywood board.This is done to keep the top of neck even and level.

Next, take soft sponge, immerse it in container of water.Squeeze it out and go over outside of piece with the moist sponge for "finished" look.

pottery wheels

pottery wheels

If greenware is to be used to hold water it is necessary to glaze the inside.
This is done by slowly pouring glaze into the neck of the vase.

If you’ve dribbled any glaze on outside, wipe it off with damp sponge.Next, decorate.Usually an underglaze color is used for floral decoration because of many colors.For just one or two colors use a colored glaze and save the extra step.Apply with a soft sable brush and create freely.

Below, after pouring glaze into vase, wait a few seconds and pour it out slowly while you rotate the vase so that all inside surfaces are covered.

pottery wheels

pottery wheels

Before placing in kiln see that it's fully dry.If bottom isn't to be glazed, dry-foot the vase: remove all traces of glaze from part that rests on the shelf.If bottom is to be glazed, stilt it to prevent it from sticking to shelf in the kiln.

When decoration is completed you must glaze vase on outside.One trick coat usually is enough.Flow it on the surface rather then brush it on.

Place ware in kiln, making sure it will clear the door so it won't get crushed.Check the shelves for glaze that may have fallen during previous firing; chip off glaze, kiln-wash any bare spot.

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