Handbook on Japanning: 2nd Edition For Ironware, Tinware, Wood, Etc. With Sections on Tinplating and Galvanizing

Excerpt

INTRODUCTION.

Japanning, as it is generally understood in Great Britain, is the art of covering paper, wood, or metal with a more or less thick coating of brilliant varnish, and hardening the same by baking it in an oven at a suitable heat. It originated in Japan—hence its name—where the natives use a natural varnish or lacquer which flows from a certain kind of tree, and which on its issuing from the plant is of a creamy tint, but becomes black on exposure to the air. It is mainly with the application of "japan" to metallic surfaces that we are concerned in these pages. Japanning may be said to occupy a position midway between painting and porcelain enamelling, and a japanned surface differs from an ordinary painted surface in being far more brilliant, smoother, harder, and more durable, and also in retaining its gloss permanently, in not being easily injured by hot water or by being placed near a fire; while real good japanning is characterised by great lustre and adhesiveness to the metal to which it has been applied, and its non-liability to chipping—a fault which, as a rule, stamps the common article.

If the English process of japanning be more simple and produces a less durable, a less costly coating than the Japanese method, yet its practice is not so injurious to the health. Indeed, it is a moot point in how far the Japanese themselves now utilize their classical process, as the coat of natural japan on all the articles exhibited at the recent Vienna exhibition as being coated with the natural lacquer, when recovered after six months' immersion in sea water through the sinking of the ship, was destroyed, although it stood perfectly well on the articles of some age. In the English method, where necessary, a priming or undercoat is employed. It is customary to fill up any uneven surface, any minute holes or pores, and to render the surface to be japanned uniformly smooth. But such an undercoat or priming is not always applied, the coloured varnish or a proper japan ground being applied directly on the surface to be japanned. Formerly this surface usually, if not always, received a priming coat, and it does so still where the surface is coarse, uneven, rough, and porous. But where the surface is impervious and smooth, as in the case of metallic surfaces, a priming coat is not applied. It is also unnecessary to apply such a coat in the case of smooth, compact, grained wood. The reason for using this coating is that it effects a considerable saving in the quantity of varnish used, and because the matter of which the priming is composed renders the surface of the body to be varnished uniform, and fills up all pores, cracks, and other inequalities, and by its use it is easy after rubbing and water polishing to produce an even surface on which to apply the varnish. The previous application of this undercoat was thus an advantage in the case of coarse, uneven surfaces that it formed a first and sort of obligatory initial stage in the process of japanning. This initial coating is still applied in many instances. But it has its drawbacks, and these drawbacks are incidental to the nature of the priming coat which consists of size and whiting. The coats or layers of japan proper, that is of varnish and pigment applied over such a priming coat, will be continually liable to crack or peel off with any violent shock, and will not last nearly so long as articles japanned with the same materials and altogether in the same way but without the undercoat. This defect may be readily perceived by comparing goods that have been in use for some time in the japanning of which an undercoat has been applied with similar goods in which no such previous coat has been given. Provided a good japan varnish and appropriate pigments have been used and the japanning well executed, the coats of japan applied without a priming never peel or crack or are in any way damaged except by violence or shock, or that caused by continual ordinary wear and tear caused by such constant rubbing as will wear away the surface of the japan. But japan coats applied with a priming coat crack and fly off in flakes at the slightest concussion, at any knock or fall, more especially at the edges....