Publication: The Clay-Worker
Indianapolis, IN, United States
SUMMER MEETING A. C. S.
A Happy Holiday Enjoyed by the Ceramists in the Ohio and West Virginia Pottery District.
The Inspection of Plants Prove Instructive and Enjoyable.
THE MIDSUMMER MEETING of the American Ceramic Society was held July 25th, 26th and 27th. Canton, Ohio, Hotel Courtland, was the initial meeting-place, and general headquarters. The three days were crowded with inspection tours of a number of the ceramic plants in and about Canton, Alliance, Sebring, East Liverpool, Ohio, and Newell, West Virginia. Social features, with surprise stunts, enlivened the evenings' entertainments. There was a better attendance than was anticipated, fully a hundred and thirty ceramists were present during the three days of joysome reunions and educational excursions.
Dueber Watch Case Factory. Monday morning a crowd of about fifty left the Hotel Courtland, Canton, Ohio, on special cars for the Dueber Watch Case Manufacturing Company's plant. The entire morning was given over to the interesting trip through this immense factory, one portion of which is used for the manufacture of the works for watches, while the other half is devoted to the production of watch cases. Of particular interest to the ceramists was the placing of the enamel on the dials, the baking, the printing of the figures on the face of same, and the rebaking. Floor after floor was traversed by the visitors, there seeming to be no end to the departments devoted to detail work, such as the making of tiny screws, and other parts, and the assembling of same. The work was so exacting, the parts so small, and almost invisible to the naked eye that the workers of necessity used large magnifying glasses.
Oil Burning System on Insulator Plant.
Wednesday morning a special interurban car carried quite a large delegation to East Liverpool, Ohio, where a reception committee from the R. Thomas & Sons Company awaited. Groups were taken through this fine factory where high voltage electrical porcelain is manufactured. R. Thomas and H. R. Holmes escorted the groups through the plant. The kiln room was visited first, where the oil burning system was inspected. Seven of twelve kilns were being burned with oil, five of which were equipped with Leader burners, while two had Maxin burners. The oil is stored in a tank with a capacity of 125,000 gallons, a 6,000 gallon tank is used for immediate supply. Heavy crude petroleum (Oklahoma oil) is used. This oil is so heavy when it is shipped in winter that it can hold a man's weight. This oil has a gravity of 2,462 degrees.
The oil is preheated to 180 degrees. The air is not preheated. The air pressure used is 8 ounces, while the oil pressure is 25 to 30 pounds. Steam can be used if desired and the system can burn either oil or gas. Gas is really the preferable material as It is easier to handle, cleaner, more economical and makes better quality of ware. Oil, however, is considered far superior to coal for their purposes. As stated by Mr. Thomas, the main thing is to hold the oil back. The fourteen ft. up-draft kiln is burned in 48 to 53 hours, about the same time as with coal, 1,600 to 1,800 gallons of oil being used. They burn to cone II fairly flat, or 2,462 degrees. An overhead carrier system, the equipment of the Louden Machinery Company, Fairfield, Iowa, is used throughout the kiln shed. This carries all green ware and saggers and runs all finished ware from kilns to packing rooms. It formerly required six experienced men five hours to handle the green saggers, now it takes but two small boys to do this work, and it is done in less time. This great saving is due to the Louden carrier system.
Manufacture of High Voltage Electrical Porcelain.
From the kiln sheds the ceramists walked to the slip house where the raw material, consisting of flint, spar, English china clay and English ball clay is stored in separate bins holding 10 to 18 cars each. Smaller bins of 2 to 3 car capacity are used for storing Albany Slip clays, Florida and some domestic china clays. The Jeffrey conveying system is employed in good stead in this department. Here the materials are weighed and mixed and placed in blungers. Water is added and the mixture agitated until all lumps are broken up and a perfect mixture obtained. Sufficient water is used to give the consistency of thick cream, this is called slip. The slip then goes through a fine screen called lawn which removes all coarse particles. Powerful pumps force the screened slip into filter presses, where the excess water passes off leaving the body in the form of thin cakes about the plasticity of putty. The next step depends upon whether the prepared body is to be used for the dry or wet process.
For the dry press process the cakes of clay from the filter presses are thoroughly dried and then pulverized. The powdered clay is then mixed with just sufficient water to dampen it but not enough to make it sticky or destroy its powdery form. The body in this condition is placed in steel moulds of small dry presses operated by hand as this enables the operator to adjust the pressure to the consistency of the clay. The operation is both rapid and accurate and well suited to all low voltage pieces such as knobs, cleats, lamp sockets, etc., but it is not suitable for pieces for high voltages on account of the porosity of the clay.
The Wet Process.
For the wet process the cakes of clay from the filter presses are piled up, beaten with mallets into a solid mass and allowed to stand for four days, in other words allowed to age, for this gives the moisture time to distribute itself evenly through the mass. When aged sufficiently the clay is pugged to consolidate it, work out air bubbles and form it into a suitable shape for working. The pugging is an important process as upon it depends very largely the freedom of the insulator from checks and air bubbles. Pieces of electrical porcelain of a diameter rather large in proportion to their height, as pin and suspension insulators, are made on jigger machines. Plain tubes are made by extrusion, long corrugated pieces, as bushings and post insulators, are turned. The delegates watched with much interest the hot blast jigger system employed here. A gas flame plays on the press and mould while in operation to prevent sticking. In one operation the die on the press spins round and down cutting the spiral grooves or threads on the inside and on its return or upward journey retraces, screwing itself out of the green piece. At the same time the indentations on the outside and top and bottom of the piece are made by mould and press. The jiggered pieces are placed in a humidity dryer (3 tracks 114 ft. long) of the Philadelphia Drying Machinery Company's make.
From the drying rooms the ceramists were escorted to the high voltage testing room where every piece of ware shipped from the factory is first tested, 65,000 volts are used in testing medium size ware.