Brief history of the Union Porcelain Works

[Trade Journal]

Publication: The Pottery, Glass & Brass Salesman

New York, NY, United States
vol. 15, no. 3, p. 41-43, col. 1-2

The Famous Old Union Porcelain Works of Brooklyn

Takes New Lease of Life Under Pitcairn Management


Writers on the ceramic art divide the finer productions of the potters' art into two classes: natural or hard porcelain, and artificial or soft porcelain; the latter being, in reality, not porcelain at all, in the true sense of the word. The wares of Sevres and Limoges, in France, those of Meissen and Berlin, in Germany, and all the best wares of China and Japan are of natural or hard porcelain; those of Staffordshire and the other English potteries are of artificial or soft porcelain. No hard porcelain is made in Great Britain. In this country a number of attempts have been made to produce hard porcelain; among them, one in Vermont, in 1810; one in New York, in 1819, and one in Philadelphia, in 1827 (it is possible the last was not hard porcelain); one at Egg Harbor, N. J.; several attempts near Flushing, L. I., and many others in various places, some twenty-five all told. All of these were unsuccessful. The only porcelain works that have ever succeeded in making hard porcelain a success in this country are the Union Porcelain Works, at Greenpoint, Brooklyn, N. Y., now under new management represented by Gilbert L. Pitcairn, son of William S. Pitcairn, the well-known Fifth Avenue importer. What, then, is the difference, and why should the hard porcelain be preferred to the soft? We answer, the difference is principally in the mode of manufacture, the manner of burning, and the entire absence of boracic acid, lead and other metallic oxides, or other poisonous substances in the glaze that covers the surface; the material employed for the body of the ware is nearly the same in both, though used in somewhat different proportions, and must be, in the hard porcelain, of much finer quality. Kaolin or porcelain clay of the very best quality and the purest of quartz and feldspar are the constituents of the body of natural porcelain, or China, as it is more commonly called. All other wares can, and do, use more or less of the common cheap ball clay. The kaolin and feldspar are in reality much the same thing, except that in the kaolin the feldspar has reached its powdered condition by a process of nature which abstracts the potash and causes disintegration.

Pure kaolin is the product of feldspar which has been, by the processes of nature, reduced to powder, while the feldspar used in porcelain manufacture is still as hard as the granite rock from which it came and has to be reduced to powder by crushing and grinding. The quartz adds the element of silica to the porcelain.

In the manufacture of hard porcelain the kaolin, feldspar and quartz, after undergoing the processes of grinding, washing and demagnetizing, of pressing, mixing and kneading, of forming, trimming and drying, all of which we shall presently describe, are ready for their first baking, which will bring them into the condition technically known as "biscuit."

At the Union Porcelain Works the molded and dried wares are placed in single layers, carefully separated and supported in the seggars, and these seggars, carefully placed one over the other, are wheeled into the upper part of the great kilns, where the heat is much less intense than in the lower part, being, as we may say, the waste heat of the lower kiln. Here, at a temperature of about 1,500 deg., they remain from thirty to thirty-five hours, and after their removal from the kiln are suffered to cool for two or three days; when taken out of the seggars they are brittle and porous, not very hard, and can, if necessary, be trimmed in the lathes. They are now ready for the glazing. The material for the glaze is the same as for the ware itself, except that the proportions are entirely different in order to make it fluent and flux at the same time that the body becomes vitreous. The glaze must be reduced to the most impalpable powder, and suspended in large tubs of water, by constant stirring. The biscuit ware is dipped into this and quickly absorbs the water, leaving the glazing compound in a nearly dry paste upon the ware. It is now looked over and cleaned off, and placed in shallow seggars (which for this purpose are made of the most refractory clays), great care being taken to protect the wares from being warped or marred in the seggars. When thus carefully placed they are put in the lower division of the kilns and the fires urged until a heat of from 4,000 to 5,000 deg. is obtained, sufficient to make the whole of each piece, glazing and body, perfectly homogeneous and vitrified. This heat is maintained from thirty to thirty-five hours, and the wares are suffered to cool for three days before being taken out.

They are now finished wares. They will not craze or crackle or stain, whatever may be the fluid placed in them and whatever the degree of heat to which they are subjected. The process of burning the soft porcelain and earthenware is, in most respects, the reverse of this.

The biscuit in the first burning is subjected to a high heat, perhaps 3,000 to 4,000 degrees; the glazing, while containing some feldspar, is largely composed of lead, borax, etc. It is applied at a low heat and forms a glaze, covering over the biscut but not at all homogeneous with it, and the ware is fragile. The process is, in every stage, easier than that for china ware, but the results are much less satisfactory.

We recur now to the history of the Union Porcelain Works at Greenpoint. A small establishment, with one small kiln, was started by a family of Germans, on the site of the present works, for the manufacture of doorknobs, etc., as early as 1854. They were made with a mixture of kaolin and phosphate of lime, after an English formula. They proved unsuccessful, and the works passed into the hands of a stock company, who succeeded in inducing Thomas C. Smith, then a prosperous architect and builder in New York, to loan them considerable sums of money.

The war came on, the company failed, and Mr. Smith found himself obliged to take the factory for his debt. Full of faith and patriotism, even in that dark hour, in his country's success in the near future, Mr. Smith began to cast about him for some way of utilizing this factory in the prosperous times that were to come. In 1863 he was in Europe, and embraced the opportunity to visit the porcelain factory of Sevres, in France, and some of tht English potteries in Stoke-on-Trent; and when he had returned home he had fully made up his mind to undertake the manufacture of hard porcelain. The factory was put in thorough repair, new buildings erected, machinery and materials procured; and after two years of experiment and a heavy outlay he put upon the market a small quantity of genuine porcelain. Finding a ready market, he increased his productions each year, and by the application of new and improved machinery overcame the numerous and formidable obstacles which beset every step of his pathway. Nowhere else, either in France or Germany, in China or Japan, had the manufacture of hard porcelain been successful without government aid and patronage; but he was not only fighting his battles without assistance from his government, but was threatened, in the very infancy of his enterprise, with the reduction of the duties on European and Asiatic porcelain; while his competitors, who were manufacturing soft porcelain, were seeking in every way to damage and depreciate his wares. But he fought on, expending over $250,000 on buildings and plant, buying a quarry of quartz and feldspar to be sure of the best; building and furnishing a machine shop where he could produce his own machinery and tools; when he found a need for a machine which would do his work better than it was done, inventing and manufacturing it; when the time came for producing decorated china, resolving to use only original designs, as he had already done in the forms of his vases and dishes; and, later on, procuring the services of an eminent artist and sculptor to aid him and his son in this part of his work. Every year has witnessed material progress, till his establishment is known all over Christendom (better, we had almost said, in Europe than in Brooklyn), and his wares are fully appreciated wherever they are known.

He has received from the various expositions their highest awards. At the present time he is employing more than two hundred hands, paying liberal wages; has a very large capital invested in the business and plant, and turns out about $250,000 of his various wares, many of them of the highest artistic beauty, each year.

Some of his vases are of exquisite design. One of them, which forms a prominent feature in our illustrations, is known as the "Keramos Vase." and was suggested by Longfellow's beautiful poem. "Keramos." We have left ourselves but small space to speak of the processes of this interesting industry, but we cannot wholly omit them. The kaolin, procured mainly from Pennsylvania, comes in lumps and powder, and is mixed with the quartz and feldspar (from Mr. Smith's own quarry at Branchville. Conn.), which has to be ground, at first coarsely and afterward to an impalpable powder. The combination of these three ingredients in a huge vat with water to the consistency of a thin paste is technically called "mixing the slip." Inside the vat a vertical shaft, supporting a number of radial arms, keeps the "slip" in a state of constant agitation, as the liquid slowly escapes from an orifice beneath into a sieve. The sieve is constantly shaken, and the "slip" continues its sluggish course down a short channel and between two sets of horseshoe magnets, some horizontal, some perpendicular. The object to be attained by these magnets is the removal of every fine particle of iron which the mixture may contain (quartz has a strong affinity for iron and other metals); every speck of the metal retained, however minute, appears as a black spot on the snowy surface of the finished china. After passing the magnets, the liquid runs into a second sieve and thence into a second vat, at a lower level, where a similar apparatus to the first keeps it constantly in motion. After passing through several of these vats the "slip" is led into storage tanks. From these it is transferred to cloth or canvas bags placed beneath the leaves of a screw press ingeniously contrived to squeeze the water from the "slip"; the material comes out of the bags a heavy dough, which is thrown into bins and kept there for months to ripen. Age improves it, and the Chinese have a tradition that the material for their old porcelain was kept for a hundred years. When wanted for use this dough is sent to the kneading machine—a very ingeniously constructed machine, of French invention — which kneads and mixes it quietly, but with the utmost thoroughness. When thus kneaded it is ready for molding.

Here we learned something which surprised us; the potter's wheel, which for more than three thousand years had been so fully identified with all fictile manufactures, is now obsolete and is abolished from the Union Porcelain Works. In its place there are long tables, before which a row of employees are stationed, and in front of each one are perpendicular and horizontal revolving disks, which are put in operation by a mere pressure of the knee on a lever. Beside each operator is a mass of the dough, irregularly shaped, perhaps in the form of imperfect tubes. The disk, or revolving head, being at rest, the operator puts upon it a mold, the interior of which is of the exact form of the exterior of a bowl, or cup. Into this he inserts one of his dough tubes and the disk is set in motion, the plastic mass being pushed with his fingers out against the side of the cavity. Then a counterpoised metal blade is brought down into the cavity, which is so adjusted and shaped as to remove exactly enough material to leave the bowl or cup of the requisite thickness and at the same time to form its interior. Sometimes these dishes, or bowls, are of oval form, and an arrangement of cams enables the operator to turn them out not quite so rapidly but yet with a fair amount of speed. The dish, cup or bowl when removed from the mold is set aside to dry and be turned off and finished, and is then ready for the first baking. Many objects do not require the revolving head, and are pressed into molds either by machinery or by the hand alone. This is the case with the handles, ears, noses, etc., of pitchers, teapots, sugar-bowls, etc., etc., as well as with most of the porcelain hardware.

Next comes the first baking, or converting the ware into biscuit. We have described this pretty fully, when showing the difference between hard and soft porcelain, but a few words concerning the kilns and seggars will be in place here. The kilns are huge cylindrical structures, 15% ft. in diameter and having two stories, the lower being about 11% ft., the upper about 9 ft., in height. The walls, which are of brick, faced inside with fire brick, are more than 3 ft. in thickness. When fired, a kiln uses about 10 tons of coal to a baking, and the combustion is continued for 30 to 35 hours. The upper story is used for the first baking, the heat being much less than that of the lower story. The seggars are round boxes made of a cheap but very refractory clay, and at these works are made with great care on the premises to insure their good quality. In them, for the first baking, as many articles are placed as can be put in without danger of damage. They are then piled into the kiln, the bottom of one seggar serving as cover to the one below it and the piles reaching to the top of the kiln. The surfaces arc separated by rings of soft clay which form a tight joint. About 30,000 to 60,000 pieces of ware may be included in one baking.

We have also described the processes of glazing and second baking, to which these nrares owe their uniform excellence. The heat generated in the lower story of the kiln is far more than sufficient to melt iron, nearly sufficient to melt platina. Great skill is required in managing the fires, and they must be checked at a point when the glaze is fluent and the body vitreous, just before the articles themselves melt. There are glass-stoppered holes in the sides of the kiln, through which the process of baking is watched. The porcelain, if it is to remain white, is now finished, and nothing more is required except to sort it over for imperfect pieces, which are consigned to the grinding mill to be pulverized and made over.

If, however, the ware is to be ornamented with colors or gilding, or is to have any artistic designs placed upon it, the process known as decoration is yet to be applied to it. The decoration is done by hand. The colors used are formed by the combination of certain metallic oxides and salts with certain fluxes which enable them to fuse into colored glasses. The oxides are usually those of chromium, iron, uranium, zinc, manganese, cobalt, antimony, gold, etc. The salts and oxides are ground up with turpentine and painted on in the ordinary manner. It is not until the heat of the furnace has driven off the oil and chemically combined the ingredients of the colors that the effect can be determined, for the hues at first are dingy and unpleasant, and give no idea to the inexperienced eye of the intended effect.

Gold is applied by dissolving the metal in aqua regia (nitro-muriatic acid): the acid is driven off by heat, when the gold remains in a state of minute division. After the ware is ornamented it is enclosed in a muffle furnace, an inner box of fire-brick, which is so arranged as to be completely surrounded by the products of combustion. After the colors are developed the articles are removed, and hand burnishing of the metallic portions completes the manufacture.


Keywords:Union Porcelain Works
Researcher notes: 
Supplemental information: 
Researcher:Elton Gish
Date completed:January 4, 2012 by: Elton Gish;