CAS

109

CAS

'th the edge of a trowel, or other implement, guided by a |th 6 ' , ^ l ' s operation is best performed on heart laths, becausee mortar is apt to cause a rapid decay in sap laths. Theating i s commonly laid in two thicknesses, the second beingPplied before the first is dry.

“AST (from the Danish , kaster, to throw), in plastering,Piece of insulated plaster, originally formed in a cavity,

6 bottom of which is the reverse of the face of the cast,the operation is thus performed : a small quantity ofr ster of Paris is mixed with water in a bason, or pan, andTed up with a spatula, till thoroughly incorporated; moreh ster is then added by degrees, till the mixture assumesmoderate consistency, such as to flow on all sides whenoil a 0n a horizontal surface ; the mould being slightlyeq or g rease( j ) to prevent adhesion, the liquid plaster isS ..J™ in, so as to fill the mould, or something more. Whenoff ene< ^ * n a sma " degree, the superfluous parts are scraped*° t ^ le middle, or in several parts at the edges ; when itSuffi 11 ' 8 t0 ' le at, which happens in a few minutes, it will be^mctently hard: then, if the mould be made of wax, it mayre m°ved by bending it away from the cast, gently at theffuite round, using the parts left on the surface asthe aieS 5 an( ' proceeding gradually towards the centre, tillhe }f^ 8t * s q uite relieved; but if the material of the mouldn mstone, a slight knock on the back will relieve it. As8t ra'n? erat *° n can on ^ ' je performed in the direction of amu '' ne , no part of the cast near the bottom of the mouldPart ' lr °j ec t from this line to a greater distance than anyhre rem °te, otherwise it cannot be drawn out without^h t Suc ' 1 projections. If more relief is required, thanWin. Can he given by the mould, the cast must be undercutjh a knife.

mav v! he ’ ra pression can be relieved of the mould, the cast8 e°Tm 8 one Piece ; otherwise it must be made in severalnts, and in such manner as may best conceal the joinings,of as ter casts are sometimes used for mouldings, insteadhe c rain g them by hand, in situations where they cannot^onveniently run with a mould,or ev exact representation of an original piece of sculpture,c °Uca U a i lv i n g animal, may be taken, whether generally^ or convex, by using the original as a mould; ondegfeg aav ing first oiled or greased the parts in a slightis . ’ P°ur the plaster, as just directed; and this impressionof 3 tur n to be used as a mould, and will give a fac-similepihT iginaL

early ment ions the casting of faces from nature, as beingThis 1 hTctice among the Greeks.

® Xa ct Use ' u ' art supplies the painter and sculptor withan 'malg e ' )resentat ‘ on3 from nature, whether of men, brutehind s S ’ ^ ra Peries, or plants ; it multiplies models of allUntiqgg n °w brought to such perfection, that casts ofexcep t s * a * ues are made perfectly similar to their prototypes,Xh e • y w 'th respect to colour and materials.

^ at es |y atro ^uction of plaster in architectural decorations,hhi^m the prevalence of the style called by us theme an ’ hut its influehce is more consDicuous during

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its influehce is more conspicuous durin;or Italian style. It was first employed inie hicij]' 1 ' 1 Paneled wainscoting, and in the enrichment of,ri buijq-^'^^orated ceilings, which wfere a prominent featureWa.st er w* gS l ' 1e P er iod. At the first onset, however, thehaun e 3 not cas t, but each individual ornament mouldedIs to 6d 1

in

the situation which it was intended after-Wastej f 0ccu Py; it was indeed merely the substitution ofjollity w °od, and the only advantage consisted in them® e Xe . w hich the former could be carved, whereas^*8 furth tl ° n °'' *he latter was difficult. This advantage61 extended at the commencement of the eighteenth2 F

century, by casting the plaster ornaments in moulds previouslyprepared for the purpose, so that from a single mould mightbe produced a number of casts, thus reducing the expenseconsiderably. Soon afterwards, another material was employedin similar decorations; this was the pulp of paper, which wasvery generally used, though not so extensively as plaster;through the poverty of the designs in this material, as wellas the imperfection in the machinery of those days, it fellinto disuse, and was at last entirely superseded by plaster.The latter material, however, could not produce the desiredultimatum, it answered very well so long as the Greek styleof ornamentation prevailed; but when this was supersededby the French , Flemish, and Elizabethan, its defects wereseriously felt: it was by no means calculated to express thefantastic forms of the latter, or the luxuriant richness ofthe former styles, especially when, as was. frequently thecase, the design was marked by bold projection and deepundercutting. This difficulty led to a new trial of thecarton pierre, or papier machd as it is now called, which, bythe aid of improved machinery, and a greater knowledgeof chemical and general science, has been advanced to a highstate of excellence, and is in every respect superior to plastercasts previously employed. One invaluable advantage itpossesses, is, that it preserves the indents and undercuttingof the original or mould, however .much recessed ; in fact, itcan readily be made to assume any form, however intricate.Add to this its hardness and durability, its adaptation toexternal ornaments, for it is known to have remained unin-jured for many years, though exposed to the vicissitudes ofthe weather; its indestructibility by vermin, its lightness,and its sharpness, and truth of outline, and its superiorityto plaster, will not be for a moment questioned. In manyof the above particulars, it is superior even to wood, to whichit is in some respects similar, for it may be cut with a sawor chisel, bent by heat or steam, and even planed and smoothedwith sand-paper. Further, its lightness will allow it to befixed in any situation, without fear of displacement, and itrequires but nails or screws, and even in some cases onlyneedle-points, to secure it firmly in its position. It holdspre-eminence over plaster, inasmuch as it will receivecolour very readily, and gilding much more so than thegenerality of materials to which such enrichment is applied.

Another article which has of late been introduced as asubstitute for the above materials, is embossed leather, whichin some instances is superior to either of them. It can bemade to assume any degree of relief short of the completeround, and it preserves all the sharpness and fineness of out-line possessed by the mould from which it is cast. Themoulds in this process are of metal, into which the leatherpreviously prepared by steaming, is forced by a combinationof hydraulic and pneumatic pressure, by which extraordinarypower the finest lines on the mould are repeated with thegreatest accuracy in the copy. It might be supposed fromthe nature of the material, that this delicacy of outline wouldbe deteriorated by time, or that the cast might be altogetherdestroyed by damp; but there is really no ground for appre-hensions of this nature, as the casts are found under allcircumstances to preserve, undiminished in the minutestdetails, the form transferred to them from the original mould,and to be improved and hardened rather than injured by age.This material has an advantage in the facility with which itcan be made to imitate old carved work; indeed, when intro-duced in the restoration of such works, it is difficult todistinguish the original from the imitation ; it may becoloured or gilded as desired. It is applicable to all kindsof interior decorations, such as cornices, friezes, &c. and hasbeen employed even in the entire paneling of rooms.