The reader who is specially interested in papier-mâché will find a series of articles on the subject in Work, Nos. 3, 6, 12, 17, 22, 25.
Pipeclay, to which calcined magnesia, whiting, or baryta may be added or omitted according to the body required, may be combined with papier-mâché and gluten, such as gum-arabic or dextrine or flour-paste, which will form under pressure, or even by hand-rolling, a very hard and finely grained substance, which is specially adapted to painting pictures. Plates or tavole are sold very cheaply in Florence of papier-mâché, which are as hard, heavy, and glossy as ebony. It is not generally realised that an expensive hydraulic-press or steam-engine is not needed by the amateur to harden papier-mâché. A common bread-roller, passed many times over the material, will work it “down and in,” quite as well as direct pressure, and very often much better.
Papier-mâché mixed and macerated with indiarubber or gutta-percha and benzole (vide Indiarubber) forms in many cases a very good substitute for leather. It can also be combined with flexible varnish to make leather. Very valuable soles can be made, or broken ones repaired, by taking card or pasteboard and soaking it in a hot solution of indiarubber. These waterproofed soles, whether of cardboard or leather, are easily prepared, as easily applied and renewed, and they will keep the true sole from wearing out forever, if renewed.
Singular as it seems, there are not many persons who are familiar with the properties or texture of so familiar a substance as paper. We know that if wetted it grows soft, but still remains, as it were, knotty, and that when chewed it does not properly dissolve. Yet if the reader will take a piece of thoroughly wetted paper, and knead or macerate it with a knife for some time with gum in solution, he will find it gradually becomes a soft paste, as flexible and as capable of moulding as putty or clay. This is not the same as papier-mâché, which consists of paper merely wet or mixed and boiled with paste, and contains fibre and knottiness. The finely macerated paper, combined with an adhesive, is ductile, impressionable, sets well, and readily receives pressure on rolling, under which it becomes extremely hard. Paper thus completely softened is readily made into sheets, and may be easily applied not only to fill up worm-holes in leaves and completely torn-away corners, &c., but is very useful for cracks and cavities in wood and other substances. It may be made up with any gums, such as gum-arabic, dextrine, fish-glue, and also with caseine, gutta-percha, varnish, and most of the substances used in cements. Paper when thus softened and mixed with, e.g., fine glue and glycerine, or with flour-paste, can be moulded and applied in ornamental forms to any surface.
There is this great difference between simply wet paper, however wet it may be, and that which is completely softened by maceration. The former is always lumpy, the latter passes under the blade of a knife like soft clay or putty. When made up with gum, glue, and glycerine, or strong paste, it is, when dry, like light wood, but less brittle. Kneaded with Indiarubber solution and glue, it becomes like leather, and can be used in several varieties of repairs. Rolled into sheets, this composition makes very good and cheap artificial leather for hangings. To manufacture these, spread the composition with a broad brush or dabber on a slate or marble table, and when rather dry pass over it a wooden roller. Some practice is needed not to roll it when too soft. If intaglio patterns are cut in the roller, the sheets will give them in relief. It is worth noting here that a great many pieces of old hangings sold as leather are really only made of papier-mâché, or carton-cuir, and glue. These hangings, whether of leather or counterfeited, can be often bought in a damaged condition very cheaply, and can be easily restored with this composition, to great profit. When mixed with white lead, or oil paint and glue, soft paper becomes harder and firmer, and under pressure is as hard and heavy as any wood. White paper with holly wood or white larch or lime-tree wood in powder, and white gelatine—better if bone or ivory dust be added, with a little Naples yellow (oil)—forms a beautiful cement.
It will be seen by what I have written that cavities, holes, cracks, and defects in most substances, including wood and leather, can be perfectly remedied with paper in combination with glue, gum, or other substances; and as it is always to be obtained, a knowledge of its nature and applications cannot fail to be of value to all menders and restorers.
Papier-mâché, like all substantial or putty-like cements, involves moulding or casting. This subject is exhaustively treated in the Vollständige Anleitung zum Formen und Giessen, by Eduard Uhlenhuth; Vienna, A. Hartleben, price 3s. On the subject of paper consult the Handbuch der praktischen Papier-Fabrikation, by Dr. Stanislaus Mierzinski, three volumes, which is not only the latest, but by far the most comprehensive, work on the subject with which I am acquainted. And here I may observe in this connection that if my references have been chiefly to German works, it is because, in the minor technical applications of chemistry to the arts, and in preparing intelligible practical treatises on such subjects, the Germans have been, especially of late, by far the first nation in Europe.
I may mention that since writing the foregoing passages I purchased, for a mere trifle, in Florence two carved heads of the fourteenth century in walnut wood. They had suffered very much from time and wanton abuse, their noses having been hacked off. I made a mixture of soft paper-paste and gum-arabic, working the two thoroughly in together with a knife-blade till the composition was as soft as butter. This thorough maceration is essential to produce a durable body. With this I filled up the holes, made new noses, and painted the whole with Vandyke brown, or brown-black. In a few minutes the restoration was complete, and the heads which had cost one franc each are now worth at least thirty francs. I should say that the portions restored are as hard as the original wood.
It is not always an easy matter to reduce paper to a perfectly soft paste, such as is called in French papier-pourri. A small quantity can be mashed with a knife-blade and flour-paste or gum. A large quantity is prepared as follows:—
Take clippings of paper and leave them a long time in water, which must be occasionally changed. When quite dissolved or soft, bray the paper in a mortar, and finally boil in very hot water. To give it consistency, add flour-paste or gum. This makes a very fine cement, which will receive the most delicate impression. It is invaluable for all kinds of dry mending.