GLOSSARY AND GENERAL INFORMATION (Pottery, for artists)
De Cerámica Wiki
Indice |
[editar] Glosario
Alumina, or Oxide of Aluminium, is one of the most abun-
dant of earths. Combined with silica it is the chief
constituent of kaolins and China clays. It imparts
refractory qualities to clays and is an indispensable
ingredient of pure glazes. Pure alumina or calcined
Aluminium is a chemical product.
Ammonia. A volatile gaseous matter, found in some
clays. Alkaline in action.
Antimony. A silver-white metallic element, used with
other oxides as a colourant or to give opacity in
glazes.
Arsenic. A non-metallic volatile element, used in
glaze making.
Barytes. A heavy spar used with clays to introduce
density and vitrescence.
Bauxite. A very aluminous earth, used in preparation
of pure alumina and to render clays refractory.
Boracic Acid. The natural and, usually, impure prod-
uct (boric acid being free from chemicals).
Borax. The combined chemical product of soda and
boracic acid. Used as a strong flux in glazes.
Calcined Bones. The residuum of burned bones, used
to stiffen artificial porcelain.
Calcined Kaolin. Kaolin after it has been subjected to heat to drive off the water combined with it.
Calcium Carbonate (Whiting). Found as a white rock, and ground to pure powder. Used with clays for soft bodies. Gives durability to glazes.
Calcium Oxide (Lime). A widely distributed earthy matter. Imparts fusibility to clays, in nearly all of which it is present in varying proportions.
Chrome, Oxide of. Used in making greens, browns, and blacks. Stands a high fire.
Ball Clay. Blue and black. Very plastic clays. Used with non-plastic materials, such as flint, stone, felspar, or whiting, to form fine earthenwares.
Cane and Red Clays. Clays coloured by the presence of ferric oxide, and used extensively for bricks, terra-cotta tiles, and common pottery.
China Clay. A yellowish-white, non- vitreous clay, prod- uct of the decomposition of granitic or felspathic rocks. Cornish China clay is exceptionally white, pure, and plastic. It is widely used with China, or Corn- wall stone and calcined bones, to make bone porcelain. Felspar is added to render it vitreous. Mixed with ball clays, pipe clays, flint, and stone, it makes the various classes of earthen and stone wares.
Pipe Clay. A very white, smooth clay. Less plastic than ball clays. Much used for making slips, en- gobes, and enamels.
Saggar Clays or Fire Clays. Coarse refractory clays strengthened by the addition of grog, used for saggars, fire tiles, and bricks.
Cobalt Oxide. The oxide of the steel-grey hard metal. Extremely valuable in pottery, making all shades of blue for under-glaze printing or staining. With iron or copper gives blue-greens.
Copper, Oxides of, and Carbonate. - Red, green, and black oxides of copper have been of the utmost value to potters. They are used to produce green, blue, turquoise, red, and crimson. Its extraordinary changes in reducing or oxidizing fires are of the greatest interest to the experimenter.
Cornish or China Stone. A rock composed of felspar and quartz. Its vitrification (about 1400 C.) im- parts hardness and density to China clays. It is a valuable constituent of glazes. First known as " moorstone " or " growan."
Earthy Colourants. Rarely used in modern commercial pottery, except for salt-glazed jars, crocks, and peasant pottery.
Felspar. A fusible rock found almost pure or in combina-
tion with potash and soda, the greater the percen-
tage of alkalies the more fusible being the spar. It
is used to replace more refractory materials in clay
and to stiffen glazes.
Flint. A pure silica with slight traces of calcium.
Found in pebble form on seashores. Calcined and
ground to a white powder, it is widely used to impart
whiteness and strength to clays. Invaluable for
bedding and packing in kilns. Used with the fluxes,
lead, borax, potash, and soda, to make glazes and
glass.
Fluorspar. A combination of fluorine and calcium,
more fusible than felspar, and of a white colour,
felspar being pink.
Galena. Lead sulphide, a highly poisonous material
used on " peasant " pottery, giving a soft, yellowish,
transparent glaze.
Gold. Used in solution for delicate purples and lustres.
Gypsum. When calcined gypsum becomes plaster of Paris, these two materials, together with the allied marble, limestone, and alabaster, are widely used in pastes (such as Parian), slips, engobes, and variously to impart fusibility or colour properties to glazes.
Iron, Oxides of. Have a wide range of colour, from
yellow to purple. They are used to stain glazes
and colour bodies. They impart fusibility to clays
and are carefully excluded from fine white bodies.
Kaolin. A fine, white, very pure, and infusible China clay, almost pure alumina and silica. Chiefly used in the manufacture of porcelain and fine earth- enware.
Lead (Oxides and Carbonates of). White Lead, Red Lead, Litharge. Are very widely used as a safe and cheap flux. Poisonous. It cannot be used in those glazes that have to stand a high fire.
Lynn Sand. (See Quartz Sand.)
Magnesia. A white metallic element present in small
quantities in most clays.
Manganese. The black and brown oxides of this hard metal are much used to stain slips and bodies, and to colour glazes brown or purple.
Marls. Amorphous deposits of lime, sand, and clay, very coarse in texture. Used in making saggars, drain pipes, and similar appliances.
Nickel. A hard metallic element, the oxides of which are found useful in preparing blacks, greys, and greens.
Nitre or Potassium Nitrate, or Saltpetre. A vitreous and aqueous compound, used in some glazes.
Plaster of Paris. (See Gypsum.)
Potash. Potassium carbonate or the leached ashes of plants. Used from earliest times as a powerful alkaline flux.
Potash, Bichromate of. Used for pinks and crystal- line effects. Poisonous.
Quartz or Quartz Sand. Like Lynn or silver sand.
This mineral is pure silica and free from lime, al-
though the sands may contain some small percentage
of iron. Used much like flint for bedding or with
alkaline fluxes for the finest glazes.
Rutile. Oxide of Titanium. Used variously to im-
part a yellow tinge to porcelain, and colour and
irregularity to some glazes.
Salt. Sodium chloride. Sometimes used in glazes,
but best known in connection with salt glazing. It
vaporizes at about 1200 C., forming a silicate
or hard, thin skin of glaze over the clay.
Silica. A hard, colourless crystalline element ; found
pure, as in quartz, or in combination with alumina
and alkalies, as in all clays. Present in all glazes.
Soda. Sodium Carbonate. Product of the decomposi-
tion of salts with acids. It is a strong alkaline flux
and much used in glaze and glass-making.
Silver Sand. (See Quartz.)
Tin, Oxide of. Used from the earliest times to impart
opacity to glazes.
Zinc, Oxide of. A white metallic oxide ; used to
brighten and stabilize glazes and colours.
[editar] POTTER's TERMS
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 biscuit-
ing. 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 ap-
plied 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.
[editar] 191
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 tena-
cious.
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 intro-
duction 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.
[editar] 192
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.
[editar] MATERIALS, TERMS, ETC.
[editar] 195
Archivo:195 Pottery, for artists.png
[editar] SEGER CONES. (STANDARD CONES. ABOUT 10 HIGHER.)
196
NUMBERS. TURNING POINTS. COLOUR, ETC.
APPROXIMATE DEGREES or
COLOUR IN KILN CONK HEAT AT WHICH MATERIALS SUITABLE TO BE FIRED NUM- CONE TURNS AT THESE TEMPERATURES
BER OR BENDS (APPROXIMATE)
Centigrade
Commences to f'J
show colour \ m 670 o
L Soft enamel or over-glaze
colours.
.019 690
Dull red
.018 710
.017 730
.016 750
Enamels on metals. Fluxes
and lustres.
.015 790
.014
815
Red to cherry 4
.013
.012
835
855
Very soft glazes and hard
enamel colours. Some
.011
880
lustres. Gilding.
.010
900
.09
920
.08
940
.07
960
Dull cherry to
.06
980
Majolica glazes or coloured
light cherry
.05
1000
glazes and stanniferous or tin
.04
1020
glazes.
.03
1040
.02
1060
Earthenware glazes. Soft
.01
1080
China glazes.
1
1100
Dark orange to
pale orange
i
2 3
1 Jww
1120 1140
Soft to hard or fine earthen-
ware biscuit.
4
1160
5
1180 Sevres soft bisque.
Yellowish white
6
7 8
9 o 1 Vitreous ware. Granite ware.
11250] S* 11 *** Stoneware.
9
1280 English bone porcelain or China
10
1300 biscuit
White 4
1 1
1320
Intense white
12] [1350 }
13 1 1 1380 ( German and Chinese porcelain.
14 J 1410 Sevres porcelain.
197
SEGER CONES. (STANDARD CONES. ABOUT 10 HIGHER.)
NUMBEBS. TURNING POINTS. COLOUR, ETC.
APPROXIMATE DEGREES OF
COLOUR IN KILN CONE HEAT AT WHICH MATERIALS SUITABLE TO BE FIBED NUM- CONE TURNS AT THESE TEMPERATURES
BER OR BENDS (APPROXIMATE)
Centigrade 15 1430
Bluish white f 16 1 1460
117 J
1480 Copenhagen porcelain.
[editar] To convert temperatures :
Centigrade into Fahrenheit. Divide by 5, multiply by 9, and add 32.
Fahrenheit into Centigrade. Subtract 32, divide by 9, and multiply by 5.
[editar] MEASURES, WEIGHTS, ETC.
APOTHECARIES
1 grain = .0648 gramme.
20 grains = 1 scruple = 1.296 grammes.
3 scruples = 1 drachm = 3.888 grammes.
8 drachms = 1 ounce = 31.103 grammes.
TROT
1 grain = .0648 gramme.
24 grains = I. penny weight = 1.555 grammes.
20 pennyweights = 1 troy ounce - 31.1035 grammes.
AVOIRDUPOIS
16 drams = 1 ounce. 16 ounces = 1 pound. 14 pounds = 1 stone. 28 pounds = 1 quarter. 112 pounds = 1 hundredweight (cwt.). 20 hundredweight - 1 ton (2240 Ibs.).
[editar] 198
CAPACITY (WET)
1 gill =1.42 decilitres.
4 gills - 1 pint - .568 litre.
2 pints - 1 quart - 1.136 litres.
4 quarts - 1 gallon - 4.545 litres.
2 gallons = 1 peck - 9.09 litres.
4 pecks - 1 bushel.
8 bushels - 1 quarter.
BOOKS OF REFERENCE
TECHNICAL
Chemistry of Pottery. Langenbeck, Karl. ^ Chemistry of Pottery. Shaw, Dr. S.
Clays. Occurrences, Properties, and Uses. Ries.
Colouring and Decorating of Ceramic Ware. Brongniart, A.
Ceramic Technology. Binns, C. F.
Notes on the Manufacture of Earthen Ware. Sandeman, E. A.
Notes on Pottery Clays. Fairie, Jas.
Pottery Decoration. Hainbach, R. TECHNICAL AND HISTORICAL
Leadless Decorative Tiles. "I _,
, _ . . } Furnival, W. J.
Faience and Mosaic, and other volumes. J
MANUAL
Pottery. I. mm. Richard.
Grand Feu Ceramics. D'oat, Tarile.
The Potter's Craft. Binns, C. F.
Practical Keramics for Students. Janvier, C. A. HISTORICAL AND ARTISTIC
Art of the Old English Potter. Solon, L. V.
Chinese Porcelain. Gulland.
Chinese Porcelain. Monkhouse, Cosmo.
Ceramic Art in Great Britain. Jewitt, L.
History of Pottery and Porcelain. Marryat.
Majolica. Fortnum, C. D. E.
[editar] 199
Potters, Their Arts and Crafts. Sparkes and Gandy.
Pottery and Porcelain in the United States (and other volumes). Barber.
Persian Ceramic Art (and other volumes). Wallis, H.
Illustrated catalogue of the Faience of Persia and Near East. Bur- lington Fine Arts Club.
BISCUIT SHAPES.
CHINA AND BALL.
APPLIANCES AND MATERIALS, ETC.
SOLD BY BALL MILLS. Wengers, Ltd. Eng. (Hanley, Stoke
on Trent.) Abbey Engineering Co. 220 Broadway,
N. Y. City, U. S. A. Hirshberg Art Co. Baltimore, Md. Mandle and Sant. East Liverpool,
Ohio, U. S. A.
Stewart & Co. N. Y. City, U. S. A. Wengers. Hanley, Great Britain. Western Stoneware Co. Monmouth,
Dl., U. S. A. W. H. Cutter, Woodbridge, N. J.,
U. S. A.
Wengers, Ltd. Hanley, Eng. Drackenfeld & Co. Murray St., N. Y.
City, U. S. A.
Professor Ed. Orton. Columbus, Ohio. Wengers, Ltd. Hanley, Eng. Drackenfeld & Co. Murray St., N. Y.
City, U. S. A. Roessler, Haslacher Chemical Co.
William St., N. Y. City, U. S. A. Fletcher, Russell. Warrington, Eng. Bellevue Perfection. Detroit, Mich.,
U. S. A.
CLAYS
CONES.
CHINA AND MODEL- LING.
MODELLING AND STONEWARE
SAGGAR AND STONE- WARE.
GLAZES.
KILNS. GAS.
KILNS. GAS AND OIL.
[editar] 200
KILNS. OIL.
KILNS. TRIAL. LAWNS AND SIEVES.
PLASTER.
QUARTZ, FLINT, FELSPAR.
SCALES. STILTS, ETC.
U. G. COLOURS, ETC. WHEELS.
Caulkins Revelation. Detroit, Mich.,
U. S. A.
Wengers, Hanley, Eng. Drackenfeld & Co. 50 Murray St.,
N. Y. City. A. Sartorious & Co. Murray St., N. Y.
City.
Wengers. Hanley Staffs, Eng. Wengers. Hanley, Eng. Drackenfeld & Co. N. Y. City. Calvin Thompkins. Battery PI., N. Y.
City.
Wengers, Ltd. Hanley, Eng. Drackenfeld & Co. Murray St. N. Y.
City, U. S. A. Golding & Sons. Trenton, N. J.,
U.S. A.
Wengers. Hanley Staffs, Eng. Hy. Troemner. Philadelphia, Pa.,
U.S. A. Trenton Stilt & Spur Co. Trenton,
N. J., U. S. A. Wengers. Hanley, Eng. Wengers. Eng.
Drackenfeld & Co. N. Y. City, U. S. A. Crossley Mfg. Co. Trenton, N. J.,
U. S. A. T. S. Nickerson. Newburyport, Mass.,
U. S. A.
THE ARTISTIC CRAFTS SERIES OF TECHNICAL HANDBOOKS
\\
A
H II
14 DAY USE
=^ RETURN TO DESK FROM WHICH BORROWED
LOAN DEPT.
This book is due on the last date stamped below, or
on the date to which renewed. Renewed books are subject to immediate recall.
m
-r-
'P LJ
MOV a 7
FOR*
LD
QCTU'64-llAM f
|...-
3 1963
t&
'64-8 AM
LD 21A-50m-4,'60 (A9562slO)476B
General Library
Unirersity of California
Berkeley
^ ! j 1
)F CALIFORNIA LIBRARY if iK . OF CALIFORI
- -* /^N\\ /T?\ .."'
3F CALIFORNIA LIBRARY OF THE UNIVERSITY OF CALIFOR
