Pottery, for Artists Craftsmen & Teachers Part 4

The clay being thoroughly wedged is rolled into b.a.l.l.s of a convenient size. For first practice they should be on the small side and moderately tough, as this allows a little more play before the ball becomes too soft.

The wheel is now started revolving from right to left (see cut). The head being clean, the ball is thrown smartly onto its centre. The hands are now wetted in a bowl of water, which is put, together with the tools, on the shelf to the right. Then gently but firmly, with hands placed as shown in Fig. 28, the ball is centred. At this stage, perhaps the most critical of all, the wheel should revolve quite briskly. The hands should be moistened if inclined to stick and the left hand held steady, the elbow pressed into the side, the forearm hard on the rest. The right hand has more freedom and coaxes the ball into a half sphere. This when dead centred is elongated, pressed down again, and re-formed into a truncated cone. The left hand still steadying, the thumb of the right is pressed firmly into the centre of the top, down and out, to hollow the ball (see page 18), but stopping short of the lathe head. At this stage the most convenient shape to form is a cylinder, its walls gradually diminishing upwards with a little fatness at the rim. To do this the wheel is slowed down a little and the fingers of the left hand inserted. The sides are felt and gently pulled up, between the left index finger and the two first fingers of the right hand, gradually higher and thinner, always endeavouring to keep the walls at an even but slightly tapering thickness. (Fig. 29.)

[Ill.u.s.tration: FIG. 28--CENTRING.]

[Ill.u.s.tration: FIG. 29--PULLING UP.]

At first two fingers only will be inserted, but as the shapes grow in size the whole of the left hand will gain admittance. Then the perfect cylinder may be modified to almost any required form. With narrow-mouthed shapes the opening must be kept as small as possible, for the clay once pulled out it is difficult if not impossible to compress it again. The centring and hollowing once mastered, the chief difficulties to avoid are getting the bottom of the walls too thin before the top is pulled up, and making the top wavy and irregular. If the latter happens, it should be at once cut back with the p.r.i.c.ker, which is also used to test the thickness of the sides and base.

When the shape has been pulled up to the required form and is sufficiently thin, the top is smoothed and fattened between the fingers. This not only imparts a look of substance to the vase and takes away any _cast_ look, but gives strength where it is most needed. The inside, if wet, can be cleaned out with the stick sponge and the outside lightly smoothed with the other sponge. For the insides of bowls or wide-mouthed shapes, a rib of slate or zinc (see Fig. 30) will be useful for obliterating ridges. The last operation is to pa.s.s the wire, held firmly to the wheel head, beneath the pot and lift it off and place it on one of the pot boards or plaster discs. (Fig. 32.)

[Ill.u.s.tration: FIG. 30--"RIB" OF METAL FOR OUTSIDE. "RIB" OF SLATE OR BONE FOR INSIDE.]

The first primitive forms are far better left frankly for what they are.

Afterwards when bigger and more finished shapes are attempted, they can be thinned and refined with the aid of the rib and a modelling tool, a considerable finish being put on before they are removed from the wheel.

With bowls or large shapes it will be found impossible to lift them off without destroying the shape in some degree. For these wood or plaster discs will be required. The plaster bats need soaking in water before use and the wood must be three-ply to prevent warping. These discs are centred on and firmly stuck to a layer of clay run out on the wheel head, and when the pot is finished they are removed with it.

[Ill.u.s.tration: FIG. 31--FINISHING WITH "RIB".]

[Ill.u.s.tration: FIG. 32--Pa.s.sING WIRE UNDER TO REMOVE.]

All this sounds very simple, but the beginner will do well first to practise and master centring the ball. Until this be done, the rest of the work is worthless. After this must be practised the pulling up, the pressing down, and the forming of truncated cones, then hollowing the ball and pulling up into a cylinder. A true cylinder accomplished, it is easy to branch out into simple wide-mouthed vase forms. As the skill increases, shapes with double curves and long or narrow necks may eventually be achieved. Throwing to a set copy induces a necessary concentration at this stage, but once a mastery is attained, shapes seem to suggest themselves.

A small mirror placed so as to reflect the true form will be found of great service. When pairs or several duplicates are required, a drawing of the exact profile must be made and a "rib," of zinc or slate, filed to fit. Without such a guide the matching up is well-nigh impossible.

[Ill.u.s.tration: FIG. 33--STAGES FROM CENTRED BALL TO TURNED SHAPE.]

When watching a clever thrower in a factory making some difficult and probably horrible vase, it is intensely interesting to see the fine forms evolved in the process. To the artist the impulse to stop him is almost irresistible. It was there that the old masters showed their wisdom and restraint. They stopped at the right moment and none of their shapes descend to the merely clever.

There is a n.o.bility about a large vase lacking in a small one. Once the appet.i.te be whetted for big pots the desire for size seems insatiable. The only way out, except for the born thrower, is the two- or three-piece vase.

The Chinese were masters of this as of every other process and we find that they frequently made vases of quite moderate size in two or three parts, sticking the pieces together with consummate skill. This process, however, should never be attempted until considerable proficiency has been gained in throwing to a drawing, for in any but expert hands it is doomed to failure. The shape must be carefully drawn out on paper and the sections marked off and then thrown exactly to size. Any deviation means endless trouble, with eventual disappointment.

For this difficult work the student unable to devote a lifetime to throwing will find a removable wheel head a necessity. Then a slotted one can be screwed on which will allow a plaster disc to be shipped back into exactly the same position, thus saving the difficult task of re-centring.

For prolonged operations these plaster discs require to be sh.e.l.lacked to prevent the work leaving.

[Ill.u.s.tration: FIG. 34--a.s.sEMBLY OF THE PARTS.]

To start with a shape as shown in the ill.u.s.tration might be attempted.

(Fig. 34.) The drawing made full size is hung in full view. Then the gauge is set to the exact width of the joint. The bottom half is first made, being cut square and true with the p.r.i.c.ker. The drawing is reversed and the upper half thrown, the neck being at the bottom with a fair amount of waste beneath. When each part is trimmed accurately to measure, they are put aside to toughen.

The top portion will stiffen just as required, leaving the neck still moist. The bottom half will need watching to prevent the upper edge drying before the base gets firm enough to support the top when attached. A damp cloth lightly wrapped round it will help to insure the ideal condition for sticking up, which is a gradually diminishing state of toughness from the base up to lip, the junction of the parts being in exactly the same state.

When fit to handle, the top half is cut through at the lip, allowing a trifle for finishing off. Next the bottom half, still firmly fixed to the bat, is slotted back into its original position on the wheel. The flat surfaces that have to be applied and stuck are now very carefully and slightly roughened, then painted with thick slip made from the same body.

These two wet edges are now applied and gently and firmly pressed into position, the wheel being slowly revolved to see if the two halves run true. When well together and apparently sticking, a little wedge of soft clay can be carefully run in all around the joint. This operation should be very thorough, and the clay wedge must be carefully welded into the sides of the joint. This is finished off on the outside with the rib and the inside very lightly smoothed with the fingers. During this process the top should be covered with a soft wet cloth, then when the joint has been made good and will stand the slight strain, the lip is finished off in the ordinary way. With three-pieced shapes the lip can be finished before sticking up, as the last part is thrown in its right position. If at any time the shape shows a disposition to leave the plaster bat, it should be stuck down with wet clay. The toughened shape can now be turned down in its upright position, cut off the bat, and the base hollowed in a chuck (see next chapter).

[Ill.u.s.tration: India. B.C. 2000]

CHAPTER VII

TURNING OR SHAVING

"A sharp spear needs no polish."--Zulu proverb.

The turning or shaving operation takes place when the green shape has dried to a _leathery_ condition. It consists in shaving the sides and hollowing the base until the thickness is uniform. The shape is thus made much lighter and rendered less liable to crack from unequal contraction.

At the same time a fine finish is imparted to the surface.

One of the handiest tools for shaving is shown in Fig. 27, no. 6, but a piece of hoop iron bent at right angles and shaped with a file will serve.

Small hollows can be finished with a modelling tool. An old piece of leather will close up and finish the surface. In factories a horizontal lathe is usually employed, the shape being fitted over a _chum_ or _chuck_. Skilled men can turn shapes down until they are scarcely thicker than tin, but this, it is needless to add, is an abuse of method even with porcelain, and quite out of place with stoneware or earthenware. All that is necessary is to trim the thick sides, hollow the base, and smooth the surface. (Fig. 35.)

[Ill.u.s.tration: FIG. 35--SECTION SHEWING TURNED & THROWN WALL OF A SHAPE.]

A simple way to arrive at this is to throw on the wheel a chuck of stiff clay to fit the shape, wide-mouthed ones being fitted over and ordinary shapes within the chuck. (Figs. 36 and 37.) A piece of soft linen is placed over this chuck to prevent sticking and the shape fitted and centred. When spinning quite truly from right to left and steadied with the left hand, the tool should be gently applied as shown in the ill.u.s.tration. Hollow the base and then shave the sides, turning all down very gradually and improve the outline as much as possible in the process.

[Ill.u.s.tration: FIG. 36--SHAVING THE BASE.]

[Ill.u.s.tration: FIG. 37--SHAVING THE SIDES.]

Care must be taken with the base. If it is not quite true it should be sandpapered to stand flat. A little experience will soon show when it is in the best state for shaving. If the clay is too soft, the tool jumps, forming ridges, or possibly cuts deeply into the form. If it is too dry, the surface crumbles and the pot is liable to break. When turned in the right leathery condition, the shavings curl off like peel from an apple and all tool marks are easily removed. A beautiful finish may then be imparted with the leather.

To end the process the shape is reversed in the chuck. Those most important parts, the shoulders and lip, are carefully rounded with a piece of felt and polished with the leather. Properly attended to, this will save much work and disappointment later on. Then with all holes filled up, all ridges, b.u.mps, and sharp edges removed, the shape is signed and put to dry.

For very delicate work in transparent glaze or under-glaze painting, the whole surface may be gone over with very fine sandpaper and polished with the hand. This may be done provided the body is a fine one, for with a coa.r.s.e body this is apt to leave the surface looking gritty. Some little practice will be necessary in throwing stiff chucks and centring the shape securely, but this once mastered, the method here described will be found to be expeditious and satisfactory for turning shapes.

A proper regard for process points to the desirability of leaving built shapes without a high finish.

Yet they also, if built carefully and stoutly, may be turned down in the above manner. The building up and turning down is somewhat tedious, but it is sometimes the only way by which a craftsman can obtain large shapes. A rather more simple process is to centre the shape upon a whirler and turn down with a sharp wire tool, finishing off lightly with a sponge and soft leather.

To accomplish this satisfactorily the shape must be fairly soft, as there can be no quick spinning motion to enable the tool to cut cleanly as in the chuck or the wheel. When the head of the whirler is of plaster, it should be well soaked in water and the centred shape stuck down with soft clay. The hand holding the cutting wire tool must be held steady at a fixed distance from the centred shape and the pot may be sprayed with water blown through a diffuser from time to time, to keep it moist. Some clays will not, however, stand much re-wetting.

[Ill.u.s.tration: FIG. 38--POSITION OF TOOLS WHEN SHAVING.]

It should not be necessary to caution the craftsman against angular profiles, splayed feet, or sharp mouldings. Such features are foreign to good pottery, however suited to metal or stone.

With taste and judgement the irregular grooving caused by the tool can be made of high decorative value. In no case should the built shape try to masquerade as a thrown shape. When the whirler is used to shave down built shapes, they may be coiled very thick at the base, thus allowing more rapid work.

The attention must then be concentrated on the profile of the inside. In this way many shapes that splay out or curve boldly from the foot may be built, which would otherwise present many difficulties in coiling.

CHAPTER VIII

TILE-MAKING

"VI thousand and fourscore of pavynge tiles delivered at Hampton Court, for to pave the Kinges new hall at XXVJs. VIIJd. the thousand."