POTTER’S TERMS
Bags.—Chimneys or walls of fire bricks built to protect the ware from flame. Baitings.—The feed of fuel during firing. Bat.—Any flat slab of plaster, biscuit, or fire clay. Biscuit.—The fired but unglazed clay. Blowing.—The shattering of the clay shape when biscuiting. Usually due to hurried firing or the sudden access of heat, and the consequent generation of steam. Blunger.—A machine for mixing clay. Bungs.—Piles of filled saggars. Chuck or Chum.—The cone or cap used to support shapes during turning on the lathe. Clamming.—The wet marl, sand, or siftings applied to cracks in the hatches or doors of kilns to retain the heat during firing. Craze.—The minute cracks that appear in a badly fitting glaze. When arrived at by design, as in some Chinese work, it is termed a crackle, but there is then no fissure. Drawing.—Unpacking the kiln after firing. Engobe.—A dip or outer covering of slip; usually applied to inferior bodies to improve their appearance. Fat.—Clays that are sticky or greasy are sometimes termed fat by potters. Fettle.—To touch up, and remove traces of seams, cast lines, etc. Fluxes.—Those materials which by their addition to paste or glaze render them fusible, although they may not always be fusible themselves. Glost.—The glazed ware, usually applied to the glaze in firing, as glost-oven.
Green.—The clay shapes before biscuiting. Jigger.—The wheel on which shapes are moulded with the aid of a jolley or profile. Joggle.—The natch or key in a mould to insure correct adjustment and prevent slipping. Lawn.—The fine mesh gauze through which glazes are strained. Long.—A clay is termed long if very ductile and tenacious. Muffle.—Usually the fire-clay box or interior of a small kiln, but applied to any kiln to the inside of which the flames have no access. Natch. (See Joggle.) Oxidizing.—The ordinary method of firing gives an atmosphere in which there is always sufficient oxygen to consume all the carbon or combustible gases. If oxygen is present in excess, it causes reactions known as oxidizing. Pitchers.—Finely ground biscuit. Added to some clays to increase refractories or porosity. Moulds made in such clays and fired are termed pitcher moulds. Potsherds.—Any broken biscuit or pot, sometimes used for pitchers. Potting.—A colloquialism used to designate the ceramic industry. Pugging.—The roll of infusible clay placed between each saggar when building bungs. Reducing.—The reaction that accompanies the introduction of smoke or gas containing carbon in a very finely divided state into a kiln during the process of firing glaze. Reduction is now widely employed in obtaining fine lustre effects. Refractory.—Hard, infusible.
Rich.—Used of clays that are long and fusible, such as red clays. Riffle.—A grooved and toothed plaster tool of steel. Saggars.—Or seggers. The fire-clay receptacles in which the glazed ware is set during the firing. Setters.—Supports used when packing friable biscuit. Short.—A word used to denote a clay that crumbles or is difficult to pull up on the wheel. Sieve.—Sometimes called a lawn, more correctly a screen for clay or slip. Slip.—The sieved clay or paste in creamy liquid condition as used for slip decoration, engobes, or casting. Slub or Slurry.—Clay mixed with water but not sieved, as with slip. Spy.—The small hole, kept plugged, through which tests and cones are observed. Stunt.—Or dunt. To crack or split on cooling. Turning.—The shaving down of the clay shape on a lathe, to impart lightness and finish. U. G.—Under-glaze (applied to colours). Vent.—A hole to aid the even distribution of fire in a kiln or to accelerate the cooling off. Waster.—Commercially, a spoiled pot; defective ones are termed “seconds.” Wedging.—The beating or slamming operation usually employed to expel air or correct inequalities just before clay is used by the thrower. Whirler.—A circular support pivoting on its centre, used in casting or banding; similar to a banding wheel, but usually heavier.