Using any one of the above shapes, break up any one of the pieces obtained in the preceding instructions, put in a saucer, add water, and see if the clay can be brought back to its original condition. INFORMATION. Pottery is one of the very oldest industries. Could use natural clay and very little heat. Use of pottery-building and for preserving writings. Presser comes nearest to original potter. Tracing early people through pottery. Sun-dry clay will crumble in time and be destroyed. Impurities in clay do not soften and are removed because of this. Metals adhere to magnets. Clay is not soluble. Clay will harden if the water is taken out. Inspection before firing saves the body for further use. UNIT 2-CLAY AND FIRE. Fact. When clay is heated (fired), it becomes hard and strong (tough), but is porous, and water will not soften it. Application.—Firing green ware (making bisque). Defective bisque ware must be scrapped. SUGGESTIONS FOR INSTRUCTION. Make up some clay with water (bat) into a cake about the size and shape of a griddle cake, put this on a sheet of iron and heat it hot as directed. After it has cooled compare its properties with those of a similar cake that has not been cooked (fired). Experiment 1.-Break up the cake obtained in the preceding experiment (bisque), put fragments in water and compare the result with those obtained in experiment 5. INFORMATION. Fired clay is used for bricks, pipes, tiles, terra-cotta ornaments, earthenware. Natural clay gives different colors under firing. The purer the clay the whiter the color. Body is mixed clay and other substances, partly to produce white color when fired. Inspection after firing does not save body for further use. UNIT 3.-CLAY AND GLASS. Fact.-Porous clay (bisque) can be coated with glass and so made nonporous (glaze). Application.-Glazing. SUGGESTIONS FOR INSTRUCTION. The following experiment can not be carried on unless it is possible to get the material fired in a regular kiln or some substitute for a kiln such as a gas or electric furnace. Experiment 1.-Take a small piece of bisque ware if it can be obtained (if not make it as above), dip it in glaze as instructed, then fire. Compare the resulting ware with the bisque ware. INFORMATION. Tiles, ornaments, porcelain and china ware, pipes, brick, earthenware products are glazed to improve their looks and wearing properties. Glaze keeps out dirt. UNIT 4.-CLAY AND COLORS. Fact.-Colors can be permanently put onto baked clay (bisque) by putting on certain minerals and then baking the clay. The colors obtained are not the same as the colors of the minerals put on. These colors (certain of them) can then be protected by melting glass over them (glazing) the same as in the case of plain baked clay (plain bisque). Certain minerals can be put onto glazed clay and when heated hot enough to melt will form colors on the glaze. (Make colored glaze.) The colors so obtained will not be the same as the colors of the minerals put on. Application. Underglaze decorating. Overglaze decorating. SUGGESTIONS FOR INSTRUCTION. Experiment 1.—On a piece of bisque make some marks or writing with the color material supplied and fire (underglaze colors). Experiment 2.-Do the same and dip before firing. Experiment 3.-Do the same with an overglaze color and fire. Note the result. Experiment 4.-On a piece of glazed ware make some figures, drawing, or writing with the color material supplied, per example 3. Fire this and compare the appearance of the fired ware with that before firing. (Fire in decorating kiln.) INFORMATION. Decorated pottery is a very old art. Tiles, porcelain, chinaware, and statuary are so decorated. Some colors can not go under glaze. Fact. UNIT 5.-HEAT. Some substances conduct heat better than others. Most solids melt when heated hot enough. Different solids melt at different degrees of heat. Application. Kilns are made of fire brick because the brick is a nonconductor of heat and so the heat does not leak out of the kiln. Kiln is made of fire brick because brick will not melt when kiln is hot enough to bake ware or melt glass. In the fire boxes of the kiln in using coal and draft we get ordinary combustion or heat. INFORMATION. Common fuels coal, oil, gas. (See Bulletin 52.) Construction of kiln. Measurement of temperature. (Measuring instruments.) (Scale.) ART IN POTTERY. DECALCOMANIA TRANSFERRING. Job.-Decalcomania transferring: Transfers patterns to bisque and glost ware by means of decalcomania printed in ceramic color on duplex paper from lithograph stones. Objective.-Must be able to transfer all decalcomania patterns to bisque and glost and to make first class pay on piece work. Auxiliary information: 1. Trade terms Material. Decal, duplex paper, size, prints, bisque, glost, names of colors by hue, names of types of ware as to use, as jugs, butters, etc. Auxiliary information-Continued. 1. Trade terms-Continued. Machines, tools, equipment.—Roller, rubbing brush, sponge. Operating.-Cutting, applying, rolling, rubbing, sponging, separating, washing off. Location-Face, back, dextrined side, rim, verge, shoulder, handle, spout, foot, inside, outside, pencil line, special terms as O. S. F. U. (outside facing user), etc., center, body. Special.-Crest, spray, bung, printer's count. 2. Stock Recognition. Of decal sheet, bisque, and glost. All ware as to style, size and use. Working properties.-Water softens dextrined surface of duplex paper. 3. Care of tools and equipment— None. 4. Safety None. Mathematics: Count to 100. Count one day's work by dozens and by printer's count. Divide circle into segments by eye. Drawing: Read design for location marks. Make location marks on ware. Science: None. DESIGNING. Job.-Designing: Makes patterns for decorating ware. Objective.--Man can make patterns in color for decorating ware to be used over or under the glaze. Auxiliary information: 1. Trade terms— Material-The grades of pencils as H, III, HB, etc.; opaque and transparent water color; the names of the colors as rose, madder, cobalt, etc.; designer's paper. Machines, tools, equipment.-Drawing instruments, compass, dividers, bow pen, ruling pen, etc. The names of the brushes as to use and size. Operating Sketching, transferring, coloring. Location.-Rim, verge, shoulder, handle, spout, foot, inside, outside. Special. Preliminary sketch, finished drawing, crest, customary designs and motifs used in the industry, period styles of decoration, color harmonies, rhythmic lines, arrangement of light and dark. 2. Stock Recognition. Of pencils, brushes, paints. Working properties.—Of colors as affected by water. 3 Care of tools and equipment— None. 4. Safety. None. Mathematics: Dividing a circle into a given number of parts. Drawing circles concentric to a specified circumference. Drawing: Pencil drawing and water color painting. Science: None. ENGRAVING. Job.-Engraving: Engraves or cuts into the surface of a copper plate the patterns to be used in decoration under the glaze, working from a design or sample. Objective. Can engrave on a copper plate or plates any underglaze pattern in one, two or three colors used in the business. Auxiliary information: 1. Trade terms Material.-Copper plate, size, Scotch stone, printer's tissue. Machines, tools, equipment.—Graver; the gravers by name as single, lining, Operating. Tracing, transferring, enlarging, buffing, planishing. 2. Stock Working properties.-Copper can be cut with sharpe steel tools. 3. Care of tools and equipment— Care to get proper edge and angle on gravers. 4. Safety None. Mathematics: To increase or reduce a segment of a circle for adapting a pattern measurement to inch. Drawing: Reducing, enlarging, and adapting patterns by redrawing. To draw a decoration for an elliptical dish, drawing from the shape of the dish itself. Science: None TRANSFERRING. Job.-Transferring: Makes up stones by transferring patterns from the original designs to the lithograph stones. Objective. Man must be able to transfer all designs to the lithograph stones by multiplying the original drawing by the transfer process. Auxiliary information: 1. Trade terms Material. A grease, a resist, asphaltum, gum arabic, rosen, dragon's blood, the various acids (as nitric, oxalic, muriatic, acetic); onion-skin paper, crayon black, turps, lithograph stone, talc, duplex paper. Machines, tools, equipment.-Blow torch, hand press, scraper, stick-up sheet, stick-up pin, rule, square, compasses, dividers, etch brush, sponge, hand roller, slab, tweezers, shears, spat, scraping knife, revolving fan. Operating.-Laying out, sticking up, fanning dry, pulling impression, fusing resist materials, washing out, making offset, registering, rolling up, gumming up. Location.-Surface of stone, edges, gripper edge, hand press, bed, back, lever, crank, dextrined side of paper. Special. Register marks, catching up, running dry, strike. Auxiliary information-Continued. 2. Stock Recognition.-Lithograph stone, the various acids by sight and smell, gripper edge of stone, rosen, dragon's blood, asphaltum, gum arabic, talc, dextrined side of duplex paper, quarters of the stone grinder. Working properties.—Of acids used in etching; of greases used in resisting the action of acids. Linear measurement to inch. Transferring measurements from one sheet to another. Drawing straight lines parallel to a given line, using square. Estimating number of strikes to the stick-up sheet by eye and by laying out. Drawing: Transferring drawings by tracing. Laying out a stick-up sheet with rule, square, and Science: Acid eats stone. Grease repels water Resist repels water. compasses. PRINT TRANSFERRING. Job.-Print transferring: Transfers patterns to bisque or glost ware by means of transfers printed in ceramic color on printer's tissue from engraved copper plates. Objective.-Worker can transfer engraved plate designs to any shape of bisque or glost and make first-class pay on piecework. Auxiliary information: 1. Trade terms Material. The transfer, transfer sheet, size decal, varnish, oil, bisque, glost, names of colors by hue, ink, names of various types of ware, as fruits, butters, bakers, creams, jugs, etc. Machines, tools, equipment.-Rubbing brush, boss. Operating.Sizing, cutting, applying, removing, drying, rubbing, washing off. Location.-Face, back, printed side, rim, body, verge, center, shoulder, handle, foot, spout, inside, outside, pencil line, special terms, as O. S. F. U. (outside facing user, etc.). Special.-Crest, spray, printer's count, bung, strike. 2. Stock Recognition. The transfer, bisque and glost ware. All ware made in factory by style and size, varnish, oil. Working properties.-Must recognize when decal varnish is just dry enough to stick the transfer on. 3. Care of tools and equipment— Should be taught care of brushes. 4. Safety None. Mathematics: Count to 100. To count one day's work by printer's count. Center a crest in a circle or other geometric figure by eye. To divide a circle into as many as five segments by eye. |