THE 7 STAGES OF CLAY

STAGE 1: RAW CLAY

This is clay in its raw, naturalstate when dug up from theground. The color and working propertiesdepend on the location where itis found and the minerals andimpurities present in the clay.

STAGE 2: SLIP

Clay that is in semi-liquid formis called Slip. It can be pouredinto molds or used as glue tobind two pieces of moist claytogether.

STAGE 3: WET CLAY (PREPARED)

Prepared clay (wet clay) hasbeen processed to removemost air bubbles and impurities.Various additives have beenincluded to make it moremalleable, fire more evenly, etc.Wet clay is also known asPlastic clay because this is thestage where it is easiest toWork.

STAGE 4: LEATHER HARD

When clay has dried to a pointwhere it holds its form butmaintains a degree of moistureso that it feels and works like apiece of leather it is calledleather hard. Although it's stillsemi moist it is strong enoughto support itself and keep itsshape when pressure is applied. This is the stage where designscan be carved or a handle added.

STAGE 5: GREENWARE (BONE DRY) Greenware is when clay is

completely air dried, and sinceGreenware is basically dried mudany contact with water will return itto its wet or slip stage. This stage isalso when a clay piece is in its mostfragile state; a tiny nudge could easilydamage the piece. Clay must passthrough this drying stage before it canbe put in the kiln for its initial bisquefiring. Any excess moisture left in apiece will expand into steam in thekiln and destroy the work.

STAGE 6: BISQUE FIRE Bisque clay is clay that has

undergone a first firing in a kiln.After about 660 degrees the heatbegins to evaporate the lastmolecules of water. When the kilntemperature reaches the maturingpoint of the clay (c. 1888 degreesfor earthenware) it transforms itinto ceramic material. At this stageit can no longer be affected bywater nor changed in any way.However, it is still porous and willnot hold water for very long.Bisque is the preparatory stagefor glazing.

STAGE 7: GLAZE FIRE

Once your piece has beenBisque fired it needs to beglazed and fired again toenable it to hold liquids. Unlikepaint, glazes cannot be mixedto create secondary colors. Glazes are chemical/mineralformulae that mature at aspecific temperature to createa glassy coating in the desiredcolor. Mixing them corrupts theformula and createsunpredictable results.