Page:The Building News and Engineering Journal, Volume 22, 1872.djvu/66

 50 THE BUILDING NEWS. Jam. 191879 aae=«q$QqT{Trli’aeGa]q]QqQqQqqQqQqQ0eeS_uo*" although oil gilding is very much used for the above purposes also, it has a much more extended field for its application than the matt and burnish process, being used by the frame gilder, the house decorator, the japanner, the coach painter, the sign, writer, the glass gilder, and for various other purposes. Oil gilding is used both for inside and outside work; and although matt and burnish gilding will stand for almost any length of time when kept ina dry room and away from the in- fluence of the atmosphere, if it is at all exposed to damp or frequent change of tem- perature it will soon begin to decay, and in many cases crack and peel off. On the other hand, oil gilding—although the filling up and ground work of the work may be prepared in exactly the same manner, and with the same material—will not be so liable to be affected by change of temperature ; the coating of fat oil forming the gold, size, or mordant by which the gold is secured to the surface of the article gilt. acts as a powerful repellant and preserva- tive against moisture of any kind. Another advantage of the oil gilding, even for picture and glass frames, is the fact that it will bear more rubbing or abrasion than matt and burnish. How often do we find it the case that the housemaid, in cleaning the pier glass, will give the frame a rub with the duster or wash- leather, which is not always dry, the result being that the gilding is cleared off the prominent parts of the ornaments and mould- ings, and black and bare places soon make their appearance, and the frame becomes shabby very soon. Oil gilding is notso liable fo injury; the two may, of course, be com- bined with advantage. Servants should never be allowed to touch gilt frames with the ordinary cloths they use for dusting the fur- niture, but should be provided with a soft silk duster, or a soft feather brush anda small pair of bellows. The dust should be lightly and carefully brushed off, not ‘‘ rubbed,” and the bellows may be used to blow the dust from the interstices, and all places which cannot be got at conveniently with the brush. Should the fraine really require cleaning, or has accidently got soiled, it is the best to send for the gilder at once, who will clean it in the manner hereinafter to be described. The groundwork or preparation to receive the gold leaf requires much care and skill in the work- ing and material. The preparation for the process of matt and burnish gilding and that for oil being essentially different, for picture frames the processes are identical up to a certain stage, but in all other cases the two are wide apart. The gold size or mordant d for each is, of course, different. The » used for matt and burnish gilding is made principally from parchment cuttings. The shreds of parchment are first purified by being well washed with water. They are then boiled in clean water, the quantity being regulated by the weight of cuttings. It is allowed to simmer gently by the side of the fire until the water has acquired a certain degree of stickiness when held be- tween the fingers, or until it arrives at a stiff jelly when cold, which fact may be easily ascertained by putting a drop upon a bit of e@lass. When this is the case, it is then poured into a clean mug, and allowed to cool. When cool it will be found that there is a certain thickness of greasy matter or scum at the top of the size, a thick sediment at i.e bottom, and a mass of clear transparent jelly between. When a portion is taken out tor use the top and bottom is cut off, and the quantity required is melted in a brown earthenware pipkin, and reduced in strength as may be required. The burnish gold size, which is so-called because it is used only for those parts which are to be burnished, is a curious substance, the manufacture of which is one of those remnants of ancient craftdom we meet with now and then—namely, a trade secret. Of course, different manufac- turers have their own special mixtures, vary- ing in quality, the principal ingredients being composed of substances very opposite in their natures—namely, bullock’s blood, pipe clay, red chalk, black-lead, size, suet, &e., the primary object being to lay a body of matter upon the surface to be burnished, which when the gold is laid on the work shall give, or allow its component parts to be pressed close by the burnisher, resulting in a firmly-pressed, close, and homogeneous surface. Here we may remark that all polished or burnished surfaces are a result of smoothness, uniformity of surface, and close- ness of texture, by whatever means it is ob- tained. ‘The various ingredients composing the burnish size are all calculated and in- tended to accomplish this end. One helps to give brilliancy to the burnish ; another keeps the composition mellow, so that it will go together under the burnisher without breaking or cracking the surface ; another gives smooth- ness. The form in which it is sold to the gilder is in a stiffish paste. When about to be used, it is mixed with the ordinary parch- ment size while the latter is hot, and well broken up with a clean brush until it is of the consistency of cream. Oil gold size is, on the contrary, exceedingly simple in its manufacture and properties. Oil gold size is a mixture of the best Oxford ochre and lin- seed oil ground together into an impalpable paste, which, on working, is thinned down with boiled linseed oil. The oil with which the yellow ochre is first ground is what is called fat oil, that is to say, oil which has either been exposed to the atmosphere for a con- siderable time and thus thickened or become fat, or the oil has been boiled until it has become thick, and it is then thinned so as to facilitate the grinding. In either case the fat oil gives the gold size a property of retaining a stickiness (technically a tack) for a con- siderable time after it might with truth be called dry. We have known this to be the ease for weeks after it has been laid on, and it is this peculiar quality which gives value to the oil gold size. The nice point under ordinary circumstances in oil gilding is to know the right state of dryness or tack, for if it is gilt too soon, the gold will have a dull shady look, and will not have that brightness and lustre it will have if the size is just in the right state of tackiness. Of course this can only be the result of experience ; but it may be taken as a rule that if we can just feel the tackiness with a clean, dry finger, and without any softness being perceptible, we may pro- ceed with the gilding with safety. The oil size may be made to dryin a given number of hours, long or short, as may be required. By adding a little raw or unboiled linseed oil, it will be retarded in drying ; and, by adding a little teribine or liquid drier, or japanners’ gold size, we may hasten it so that it will be ready for gilding in from two to four hours, as may be desired. ‘The ordinary time occu- pied by good oil gold size in drying is from twelve to sixteen hours ; and, where this time can be afforded, or even longer, the gold will be all the brighter for it, as all forcing matter has a tendency to injure the quality of the gilding. Quick size, or what is commonly known as japanners’ gold size, is a very useful article for gilding, bronzing, &c., its quick- drying qualities causing it to be used for all gilding where despatch 1s required. It is also much used for mixing with all such cclours as are bad driers, or for such paints as are re- quired to dry immediately, and for this pur- pose it is invaluable. Field, in his ‘* Chro- matography,” says japanners’ gold size is very variously and fancifully prepared, often with needless, if not pernicious, ingredients, but may be simply and to every useful purpose prepared thus: Powder finely of asphaltum, litharge, or red lead, and burnt umber, or manganese, each one ounce, stir them into a pint of lin- seed oil, and simmer the mixture over a gentle fire, or on a sand bath till solution has taken place, scum ceases to rise, and the fluid thickens in cooling, carefully guarding it against taking fire. If it is now kept at rest in a warm place it will clear itself, or it may be strained through cloth, and diluted with turpentine for use. The same methods are applicable for the same purposes with other oils. Another quick size, principally used by the scene-painter, is made by melt- ing glue, resin, and common treacle to- gether in a common glue-pot ; it is used hot, and the metal leaf laid on at once before the size has had time to dry. It will be seen from what we have said as to the nature and properties of sizes or mordants that, inde- pendently of all other qualities, they must possess the primary condition to be observed is cleanliness, for, except the size be perfectly smooth and free from grit, bits of skin, or other extraneous matter, no good work can result. In all cases when about to use the oil or other size, it is indispensable to strain it through suitable strainers—the oil size through fine silk, and the other through several folds of fine muslin; this ensures its smoothness. Raw linseed oil should never be mixed with japanners’ gold size to retard its drying. If the size is required to hold its tack for a longer time than usual, it is better to mix with it a little of the ordinary ground white lead, or a little ochre ground in oil. This not only helps it to keep its tack longer, but serves to give the size a slight body, which enables the workman to see every touch he puts on his work. Havin now described the mordants or sizes use both in distemper and oil gilding, we may proceed to show how the various works should be done, and in speaking of matt and burnish gilding we shall, in order that the process be clearly understood, have to de- scribe the manner in which the ground- work is prepared before it is ready to lay on the gold. It will, no doubt, surprise many persons to know that on an average there are about fourteen coatings of sub- stance laid on the woodwork of a frame, and that there are also five or six processes of smoothing or rubbing-down, making twenty times the workman has to go oyer his work before it is ready for gilding, between each of which the work has to dry before the next coat can be put on. I shall have no objection to answering any questions bearing upon the subject matter of each article, or to receive any suggestions or information relating thereto. (To be continued.) > ARCHITECTURAL ASSOCIATION. HE usual fortnightly meeting of this Associa- tion took place on Friday evening last, Mr. Rowland Plumbe, President, in the chair. Mr. A. R. Brede was elected a member, and it was announced by the Secretary that Mr. T. Roger Smith had (in compliance with the request of the Committee of the Association) consented to act as the representa- tive of the Association on the Committee of Selec- tion for Architectural Drawings in the International Exhibition of 1872. Mr. Roger Smith served the Association in the same capacity in connection with last year’s Exhibition. Mr. A. Payne, A.R.I.B.A., then read a paper ON LONDON AS IT Is AND AS IT MIGHT BE. In many respects there is no city in the world to be compared to London. Its vast extent and popula- tion, and its boundless wealth, form an inexhaust- ibie theme for its panegyrists, and it would be per- fectly absurd to compare any city, ancient or modern, with it in commercial importance and activity. Even in natural situation, it is to be doubted whether many cities excel London, whether we look at the central parts, rising by a gentle slope from the bold curve of the river from London to Westminster, or the natural beauty of the suburbs round the heights of Hampstead, High- eate, or Sydenham, or along the banks of the Thames as far as Richmond. And yet, with all these ad- vantages, it cannot be denied that London is not so attractive as it ought to be. No one who wishes to pass a pleasant existence, with those advantages which are only to be obtained in a metropolitan city, would hesitate to choose Paris in preference to London. Mr. Payne divided what he had to say under four heads, as follows:—Firstly, Loudon is abominably dirty, and there is no reason why it should be so dirty. Secondly, itis much more smoky