Home › Pottery › Chinaware

Chinaware

erly selected, carefully washed from impurities, and again dried. It is then finely sifted, and most accurately mingled with quartz, ground very fine, to which then is added some burnt and finelypulverized gypsum. This mass is worked with water to a paste and duly kneaded; it is usually suffered to lie in this state for years. The vessels and other goods formed of this mass are first moderately burnt in earthen pots, to receive a certain degree of compactness and to be ready for glazing. The glazing consists of an easily-melted mixture of some species of earths, as the petrosilex or chert, fragments of porcelain and gypsum, which, when fused together, produce a crystalline or vitreous mass, which, after cooling, is very finely ground, and suspended in a sufficient quantity of water. Into this fluid the rough ware is dipped, by which the glazing matter is deposited uniformly on every part of its surface. After drying, each article is thoroughly baked or burned in the violent heat of the porcelain furnace. It is usual to decorate porcelain by paintings, for which purpose enamels or pastes, colored by metallic oxides, are used, so easy of fusion as to run in a heat less intense than that in which the glazing of the ware melts.

To make Delftware.

This is a kind of pottery made of sand and clay, and but slightly baked, so that it resists sudden applications of heat. Articles made of this are glazed with an enamel, composed of common salt, sand ground fine, oxide of lead, and oxide of tin.

The use of the latter is to give opacity to the glaze.

To make Chinaware.

The composition of the eastern or proper chinaware, according to accounts that have great marks of authenticity, is from two earths; one of which is, as was before mentioned, called petunse; the other a refractory earth, called kaolin.

The preparation of the petunse, or aluminous earth, is by pounding the stone till it is reduced to a very fine powder, and then washing it over to bring it to the most impalpable state, which is thus performed: After the stone is rendered as fine as it can be by pounding or grinding, the powder must be put into a large tub full of water, and, being stirred about, the upper part of the water must be laded out into another tub, by which means the finest particles of the powder will be carried into it. The water in the second tub must be then suffered to stand at rest till the powder be subsided, and as much as can be laded off clear must be put back into the first tub, and there being again stirred about, and loaded with a fresh quantity of the most subtle part of the powder, must be laded again into the second tub as before, and this must be repeated till none be left in the first tub but the grosser part of the stone, which, not being of a due fineness, must be again pounded, and treated as at first. The fine powder obtained in the second tub, must be then freed from the water, by lading off the clear part, and suffering what remains to exhale, till the matter becomes of the consistence of soft clay, when it will be fit to be commixed with the kaolin for use.

The kaolin is prepared in the same manner by washing over; but some specimens are so fine, that there is no occasion for this or any other purification. From these two mixed together, the clay or paste is formed; but it is said that the proportion of the respective quantities is made to vary according to the intended goodness of the ware, the best being made from equal quantities, and the worst from two of the kaolin to one of the petunse.

To make Saxon or Dresden China.

The Saxon composition, of which the chinaware is formed, is greatly similar to that of the eastern. In the place of the petunse, a stone is used, which is improperly called in the German language, bleyspatt, or spar of lead. It is a stone of a very opposite nature, as spars are calcareous, and will, on calcining, become lime; on the other hand, this stone is of a vitreous nature. This spar is of a very hard texture, and of a light flesh-color, or pale whitish red. It is prepared by pounding and washing over, which may be done as above directed, and it is then ready for compounding with the mica. The mica is employed in the Saxon composition for the other ingredients; and is likewise prepared by grinding and washing over, when it is not in a perfect and pure state; but when it is entirely clean, it may be tempered with the texture, thoroughly broken, and it will be of the consistence of soft clay.

The two kinds of earth being prepared in the state of a soft paste, they are to be incorporated and blended into one mass, which is done by rolling and stirring them well after they are in the same vessel, and then kneading them with the feet till they are thoroughly united. When the compound mass is formed, it is made into cakes, or square pieces, and put by layers into cases of wood or stone, which must be placed in a moist situation, and left for 2 or 3 months; during which time a kind of ferment enters into the mixture, by which the parts of the different matter combine and form a substance with new qualities, unknown while separate. This change shows itself upon the whole mass by a fetid smell, and a greenish or bluish color, and a tenacity like that of clay, or the argillaceous moistened earths. If the time of keeping the paste in this condition be prolonged to a year or more, it will further improve its qualities, but great care must be taken to prevent its becoming dry; to prevent which, there may be occasion to water it. When, however, the described qualities are found in the matter, it is fit for use, and vessels, etc., may be wrought of it without any other preparation, the case below excepted.

Composition of English China.

The following composition will produce wares, which will possess the properties of the true china, if judiciously managed.

Mix the best white sand, or calcined flints, finely powdered, 20 lbs.; of very white pearlash, 5 lbs.; of white calcined bones, 2 lbs. Temper the whole with the gum Arabic or senegal, dissolved in water. This requires a considerable force and continuance of heat to bring it to perfection, but it will be very white and good when it is properly treated.

Where mica can be obtained, it is preferable to calcined bones, and as it will form a kind of paste for working, a weaker gum-water will answer the purpose. To Bake Chinaware.

The furnace for this purpose may be constructed in the same manner as the potter's kilns usually are. The size of the furnace should be according to the quantity of ware required to be baked; but it must not be too small, lest the body of fire may not be sufficient to produce the requisite heat. The caffettes, or coffins, to contain the pieces when placed in the furnace, are the most material utensils. They should be of good potter's clay, with a third of sand, and are generally made of a round form, with a flat bottom, the rim forming sides, being adapted to the height of the pieces to be inclosed.

The furnace and caffettes being prepared; the ware to be baked must be sorted in the caffettes in the most advantageous manner as to room, and as many caffettes must be set upon them as the furnace will conveniently contain, leaving space for the free passage of the fire betwixt the piles: take care to cover over the uppermost caffettes in each pile, then close the mouth of the furnace, and raise the fire so as to heat the caffetes red hot in every part, and keep them red hot for 12 or 14 hours. It is then to be extinguished, and the furnace left to cool gradually; and when little or no heat remains, the mouth may be opened, and the pieces taken out of the caffettes; when they will be in a condition to receive the glazing, or to be painted with such colors as are used under the glaze.

To make Tobacco-pipes.

These require a very fine, tenacious, and refractory clay, which is either naturally of a perfectly white color, or, if it have somewhat of a gray cast will necessarily burn white. A clay of this kind must contain no calcareous or ferruginous earth, and must also be carefully deprived of any sand it may contain by washing. It ought to possess, besides, the property of shrinking but little in the fire. If it should not prove sufficiently ductile, it may be meliorated by the admixture of another sort. Last of all, it is beaten, kneaded, ground, washed, and sifted, till it acquires the requisite degree of fineness and ductility. When, after this preparation, the clay has obtained a due degree of ductility, it is rolled out in small portions to the usual length of a pipe, perforated with the wire, and put, together with the wire, into a brass mould, rubbed over with oil, to give it its external form; after which it is fixed into a vice, and the hollow part of the head formed with a stopper.

The pipes, thus brought into form, are cleared of the redundant clay that adheres to the seams, a rim or border is made round the head, they are then marked with an iron stamp upon the heel, and the surfaces smoothed and polished. When they are well dried, they are put into boxes, and baked in a furnace.

To make White Glaze.

Take 26 parts of glass, 7 parts litharge, 3 parts nitre, 1 part arsenic, part blue calx; either fritted in a glass oven or not. Black Glazing.

Take 8 parts of red-lead, 3 parts of iron filings, 3 parts of calcined copper, and 2 parts of zaffre.

This, when fused, will produce a brown-black; but if wanted a truer black color, the proportion of zaffre must be increased.

Silicious Glaze without Lead.

M. Hardsmith proposes the following in place of the ordinary lead glaze: Take boracic acid, 15 lbs.; calcareous spar, 5 lbs.; wood charcoal, 1 To make Cream-colored Glaze.

Take 60 parts of Cornish stone, 20 parts flint, and 120 parts white-lead. Stained with 1 oz. of smalts, as above.

To form a Yellow Glaze.

Take 2 parts of litharge, 2 parts tin-ash, and 1 part antimony.

To prepare White Glaze.

Take 15 parts of Cornish stone, 10 parts flint glass, 5 parts anica flint, 5 parts nitre, 5 parts bo. rax, 1 part common salt, and 1 part sal soda; fritted in a glass oven. Then add 2 parts frit, as above, to 1 part white-lead. Send to mill to grind very fine, and stain with 7 oz. blue calx.

To make a Mixture for Glaze.

Take 20 lbs. of white frit, 10 lbs. flint, 26 lbs. stone, 50 lbs. lead, and 4 oz. of blue.

To make a Mixture of Glaze for Printing Blue.

Take 6 parts of white frit, 5 parts flint, 13 parts stone, 25 parts lead, and 55 parts glass.

To make a Shining Black Glaze.

Take 100 parts of lead, 18 parts flint, and 40 parts manganese.

To make a Purple under Glaze.

Take oz. of fluxed blue, 1 oz. manganese, 1 oz. red-lead, and 1 oz. flint.

To prepare an Orange Sponge Dip.

Take 1 qt. of yellow slip, to 1 oz. zaffre.

To prepare a Brown under Glaze.

Take 8 oz. of glass antimony, 16 oz. litharge, 3 oz. manganese, and 4 drs. blue calx.

To prepare a China Glaze.

Take 42 parts of flint-glass, 3 oz. blue calx.

Stain. 16 oz. flint-glass, 1 oz. red-lead, 1 oz. arsenic, and 1 oz. nitre. - White enamel. Run down in glass oven; then send with the above stain to the mill, 8 parts of white enamel, dry it and it will be fit for use. Eight parts of the above mixture (stain and white enamel), 6 parts dry flint, 14 parts Cornish stone, 24 parts white stone, which, when sifted, is fit for use.

To prepare a China Glaze for Flotts.

Take 27 parts of flint, 15 parts nitre, 4½ parts lime, 3½ parts stain. This run down in a glass oven, and, when sent to the mill, add 75 parts of glass, 15 parts lead, 10 parts white enamel; add 2 pailsful of lime, and when it comes from the mill, add 135 parts of lead. Stain to the above, 10 parts of glass, and 5 oz. of blue.

To prepare White Enamel.

Take 7 oz. of arsenic, 12 oz. potash, 6 oz. nitre, 5 oz. glass, 2 oz. flint, and 3 oz. white-lead.

To prepare China Glaze.

Take 56 parts of stone, 46 parts borax, 18 parts lb. Powder the mixture, and calcine to complete glass, 15 parts flint, and 40 parts lead. fusion; allow it to cool; powder again and apply it as the common lead glaze is applied.

To make China Glaze for Printing Blue Frit.

Take 10 parts of glass, 2 parts lead, and 3 or 3 parts blue calx, as required.

To make White Frit.

Take 16 parts of glass, 5 parts lead, 1 part arsenic, 2½ parts nitre. Take 11 parts white frit to the whole of blue frit, and grind them together. Then take of the mica frit, 8 parts of the above, 5 parts flint, 13 parts Cornish stone, 23 parts lead, and 6 oz. common salt. To prepare Green Edge Glaze.

Take 20 parts of lead, 60 parts stone 20 parts flint, and 10 parts ground glass.

To prepare Materials for Common Ware.

Take 25 parts of flint, 60 parts stone, 95 parts lead, and 8 parts frit.

To prepare Glaze for Green Edge.

Take 175 parts of lead, 100 parts stone, and 35 parts flint.

To prepare Fluxes for Blue Printing.

Take 5 parts of blue calx, 5½ parts coke stone, 1½ parts glass, and 1 part flint.

To prepare Flux for Black Printing.

Take 7 parts of flint-glass, 24 parts red-lead, and 2 parts borax.

To prepare Red Flux.

Take 5 parts of lead, 1 oz. of borax, and 12 oz. of glass.

To prepare Black for Printing.

Take 1 part of calcined copper, 14 parts red flux.

Passed through the enamel kiln, 1 of calx, sent to the mill for grinding.

To prepare Copper Black.

Take 1 lb. of calcined copper, pounded fine, and put into the enamel kiln, and it will come out black. Then 14 oz. of red flux, put through the enamel kiln, second time; then 1 of the above, and 14 of flux, ground fine for use.

To prepare Red for Printing.

Take green copperas calcined to a fine powder, wash it well 10 or 12 days, and dry it (colcothar); 1 of the above to 6 of red flux.

To prepare Umber Black.

Take 5 oz. of umber, 2 oz. borax, 1 oz. blue calx. One of the above to 2 flux, as under; 74 flint-glass, 2 red-lead, and 2 borax.

To prepare Black.

Take 3 oz. of calcined umber, 1 oz. borax; run down together. This will fine with gold.

To prepare Oil for Black Printing.

Take pt. of linseed-oil, boiled well until of a proper consistence, to which add a small quantity of Barbadoes tar, prepared the same way.

Another. Take 1 qt. of linseed-oil, 4 oz. flowers of sulphur, 4 oz. balsam of sulphur, 8 oz. black rosin.

To Form a Stone Body. the latter case, 2 lbs. of salt may be also kept out of the composition. The reason for this change is, that if the composition contain so large a proportion of salt, and the glazing be not fluxed for a long time after it is laid on the ware, it will be apt to be dissolved by boiling water, and peel off, if it be exposed to the action of it for any long time.

Another. Take of sand, 40 lbs.; of wood-ashes, perfectly burnt, 50 lbs.; of pearlash, 10 lbs.; of common salt, 12 lbs.

This will make an admirable glazing, where the ashes are pure, and a strong fire can be given to flux it when laid on the ware. It will be perfectly free from the imperfection of the above, and will be very hard and glossy, and where the expense can be afforded, it may be made more yielding to the fire by the addition of borax, in which case no alteration need be made in the proportion of the other ingredients.

To Prepare Masticot used as the Ground of Glazing.

Take of clean sand, 1 cwt., of soda, 44 lbs., and pearlash, 30 lbs. Calcine the mixture.

Masticot for White Glazing.

Take of masticot, prepared as in the preceding, 100 lbs.; calx of tin, 80 lbs., and of common salt, 10 lbs. Calcine and powder this composition three several times.

The calx of tin is prepared and sold under the name of putty. Its goodness consists in its whiteness and purity; the first of which is easily known by comparing it with a specimen of any that is known to be good.

Another Preparation.

Take of mastic, 10 lbs.; red lead, 60 lbs.; cal- Take 2 parts blue clay, 2 parts china clay, 4 cined tin or putty, 20 lbs., and of common salt, parts composition.

To Form an Egyptian Black Body.

Take blue clay, 30 parts; black marl, 5 parts; calcined car, 25 parts; manganese, 2 parts.

Common Glazing for Earthenware. 10 lbs. Mix them, and calcine and powder the mixture several times.

Another. Take 2 lbs. of lead, and somewhat more than 1 lb. of tin. Calcine the two metals till reduced to a powder, by the means used by potters. Then take 2 parts of these ashes, 1 part Take of white sand, 40 lbs.; red-lead, 20 lbs.; of white sand, calcined flints or broken white glass, pearlash, 20 lbs; common salt, 12 lbs. Powder this sand by grinding before it be mixed with the other ingredients, and then grind them together, after which, calcine them for some time with a moderate heat, which must be less than will make them melt and run to glass; and when the mixture is cold, grind it to powder again, and, when wanted, temper it with water, and it will then be fit for use.

The proportions of these ingredients may be varied occasionally, for, where the glazing can be fluxed conveniently with a very strong fire, the quantity of sand may be increased to 60 or 70 lbs., which not only renders the glazing stronger, but makes a saving in the expense. The proportion of pearl-ashes may likewise be diminished, or they may be wholly omitted where the ware is designed for very coarse purposes, and not for domestic uses, where the lead is very improper, being extremely apt to be corroded by acids, and to produce a very unwholesome substance. On this account, where good manufactories are established, the lead ought to be excluded from the composition of the glazings, and other fluxes used in its stead, as in the following:

Transparent Glazing for Earthenware.

Take of white sand, 40 lbs.; of pearlash, 21 lbs.; and of common salt, 15 lbs. Calcine, and proceed as above.

Where the expense is no object, this glazing may be improved by adding 1 or 2 lbs. of borax, and dimirishing the pearlash, in the proportion of 6 lbs for 1 lb. of borax added, or 10 lbs. for 2; in and pint of common salt. Mix well together the several ingredients, and set the matter to bake in a proper furnace, and urge it at length to melt.

The trouble of calcining the tin and lead may be saved here, as well as on the occasions abovementioned, by procuring them already reduced to a proper state.

Another. Take 14 lbs. of lead and 1 lb. of tin.

Reduce them to the state of a calx, and then take of the calcined matter, 8 parts, and of calcined flints and common salt, each 4 parts. Bring the mixture, by heat, to a state of fusion.