Newspaperman given tour of R. Thomas and Sons

NEWSPAPERMAN SHOWN THRU'

ONE OF THIS CITY'S BIG, BUT

LITTLE UNDERSTOOD FACTORIES

There are very few residents of East Liverpool who are not familiar with the process of manufacturing ta­ble ware, but ask some one not con­nected with some of our porcelain plants, how are obtained those thous­ands of porcelain electric insulators, house knobs, bracket insulators, insulating tubes and porcelain protector mountings for electrical fixtures, and you will discover his knowledge is much more meagre on this particular subject.

H. R. Holmes, of the R. Thomas & Sons company, this city, was kind enough to show a newspaper man in company with General Manager Frank Swaney of the local Bell Telephone exchange, through the Thomas plant. Under Mr. Holmes' guidance the first point visited was the clay storage bins into which the raw materials are dumped from the cars, and in this month's "Telephone News" the story of the trip was printed:

"Contrary to the general impression," said Mr. Holmes, "our materials are brought from a distance — some even from abroad. When James Bennett started the first pottery here in 1840, he used local clays to make 'yellow ware' but in 1873, with the introduction of white ware, the clays began to be shipped in. The real cause of East Liverpool's continuation as a pottery center is the large body of skilled workmen who live here, and largely own their own homes They may change employers occasionally, but they don't like to leave the community.

"While we are at the starting point of the raw materials," continued Mr. Holmes, "let me tell you something about them. First we have the pure clay, or kaolin, which consists of alumina, silica and water. It is form­ed by the decomposition of certain kinds of granite, and is found in beds laid down as sediment from prehistor­ic streams. In most of these deposits the kaolin is mixed with sand, iron or lime as impurities, the mass as a whole is simply called clay. In devel­oping new forms of pottery, we start from the chemical analysis of old tried mixtures. Since the form of aggrega­tion of the components also influences the results, we must experiment with many mixtures having perhaps the same chemical analysis, but being brought together in varying proportions from different deposits. The characteristic feature of clay is its plasticity when wet; this is due to the small size of the particles and to their shape; their flatness allows one to slide smoothly over the other, the water film serving as a lubricant. When the clay is baked or 'fired' the particles are softened and stick together when cool. When this soften­ing goes so far as to melt the surface of the particles, the material is said to he vitrified. Glassware is a special kind of pottery in which the entire mass is melted and is transparent on cooling; it consists of lime and silica (sand). As alumina is added, the material ceases to be transparent and becomes less and less translucent; examples are milk glass and the finest grades of porcelain, Here only should the name of 'porcelain' be used; the opaque, vitreous material which comes next is properly called 'stoneware.' Of this is made all elec­trical ware. Non-vitreous material is called earthenware; a good example is the red brick formerly used for building. If you compare the fractured surface of a 'porcelain' insulat­or with that of a soft red brick, you will notice that the surface of the insulator has a slight luster, while that of the brick is dull. A drop of ink on the insulator spreads but lit­tle; the brick, however, behaves like blotting paper. Sewer pipe is vitri­fied, to retain water; drain tile is not vitrified, to allow water to soak through it."

Mr. Holmes then showed how the clays are drawn from the bins into a scale car which weighs them, and from which they are dumped into the "blunger," a tank having an arrange­ment of knives turning in it to break up the clay and mix it with its own weight of water. The charge is about 3,000 pounds of clay, and an hour is required to reduce it to the consist­ency of thick cream. Then it is drawn into a tank called a "rough agitator," in which a paddle wheel keeps the mixture moving. A pipe feeds the liq­uid onto a screen of fine cloth, which is kept agitated by machinery; this screen rejects all coarse particles. The liquid then goes to another stor­age tank, which also is agitated by a paddle wheel. To separate the clay from the water, the liquid is pumped into one or more of a group of clay presses. One of these consists of a string of sheets of canvas, clamped at their edges between iron plates to form a sort of accordion-plaited bag. When the bag is full of clay, each plait is broken open by releasing the press and the sheets of clay are taken out. Here comes the dividing point between the wet and the dry process of pottery; as electrical porcelain is made mostly by the dry pro­cess, we will follow it first.

The sheets of clay, which look like giant pancakes, are laid on upper floors of the building near the kiln chimneys. When they are dry, they are ground to powder and then mixed with just enough water to make a handful of the mass retain its shape after being squeezed in the hand The material is then fed through chutes to the molders. In front of each man is a press carrying the two parts of a steel die. In operation, the molder oils the die with a brush, and then fills the die with the moistened clay. A whirl of the handle brings it down until the material has been compres­sed into every corner of the die. The die is then opened and the pressure of a foot lever lifts the plate from the lower half. The molder puts it on one of the boards. Minor imperfec­tions are dressed up by girls, who re­move the "fins'' of clay which project where the two parts of the die join. The blocks are then dried in hot-rooms, when they are ready for the kiln.

Most small pieces of electrical porcelain are manufactured by the dry process, as the compliated [sic] complicated forms can be most accurately turned out at the minimum cost, larger shapes, such as high-tension insulators, are made by the "wet process," which is that used by the potter since the discovery of the art. The clay is used in the plastic state, being moist enough to be readily kneaded with the hands. When it comes from the clay press it is passed through another press to render the mass compact and free from air bubbles The column of emerging clay is cut into sections and sent to the molders. The old method was for the potter to mount a lump of soft clay on a flat, revolving table with his hands, work it up into a bowl, a vase, a jug or whatever his fancy suggested. Modern industry requires the production of many copies of the same design, and factory economy has substituted mechanical forms for the potter's hand. When the work is of circular shape, a plaster-of-Paris mold is made for the outside. A lump of soft wet clay is placed in the mold and roughly shaped by a conical mal­let. The mold is set on the "wheel and rotated, while the potter contin­ues the rough shaping with his fin­gers. Then a mold-board, carried on an arm, is slowly brought down. Scraping away the clay from the high spots, it fills up the low ones, and the inside of the work quickly assumes its finished shape. A helper now lifts the mold and places it on the head of a carrier, who takes it to the drying rack and lets the clay dry partially before tipping it out of the mould.

Porcelain tubes are made by a press which is filled with moist clay. The descending piston forces the clay through the ring openings former by a number of rods attached to the pis­ton and projecting through holes in the opposite end of the cylinder. The tubes are laid out on boards and car­ried to the "upsetting machine." Being cut to the right length and drop­ped into a tube, a die descends upon the projecting clay and forms it into the "head" of the tube. The tubes are then dried before firing.

Protecting Ware from Flames.

In order to protect the ware from direct action of flames in the kilns, it is placed in earthware boxes called "seggars." The seggars are then piled one upon the other to the height of the kiln-chamber, usually 15 to 20 feet. Between each one is a strip of moistened clay, to give a tight joint. When the kiln is filled, the doors are closed and sealed with clay and the fires are lighted. All East Liverpool potteries use the cheap natural gas of West Virginia, which gives a uni­form and easily controlled heat. In various parts of the kiln groups of these test cones are placed so they can be seen through peep holes in the side of the kiln. The material of the test cones is such that it softens at different temperatures and bend over. The man in charge endeavors to bring up the temperature of the kiln uniformly during 55 to 60 hours to a point at which the first two cones will fall, but not the last. The first is then extinguished and the kiln al­lowed to cool in from two to three days until it can be entered.

Ware which has been fired but once is called "biscuit" and is somewhat absorbent; hence it must be glazed to shed water readily. The glaze is simply a wash of clays mixed to have a low melting-point. The ware is washed in water, then dipped in the glazing wash, dried and replaced in the furnace, where it is given anoth­er firing The brown glaze on outside insulators is to render them less con­spicuous to small boys and others who might consider them fair targets.

Inspection of Articles

The smaller articles require only an inspection for defective form, but strain to each insulator by a testing electrically and mechanically. The mechanical test is the application of strain to eah [sic] each insulator by a testing mahine [sic] machine which places an insulator under a test of 17,000 pounds. The board back of the machine is to proect the operator from flying chips in case a defective insulator "lets go."

The electrical test consists in running wires through the grooves and laying them across the two wires of a 15,000-volt circuit. A faint hiss marks the throwing of the switch, followed sometimes by the crackle of the discharge through a defective piece.

Larger insulators for transmission lines are tested both in detail and assembled, and when one of these breaks down under 200,000 volts the sight is a fine one.