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Page 2
Painting on Zinc or on Galvanized Iron 49
Bronzing Compositions 49
Golden Varnish for Metal 51
Carriage Varnish 51
Metal Polishes 51
Black Paints 52
Black Stain for Iron 53
Varnishes for Ironwork 55
SECTION VI.
PROCESSES FOR TIN-PLATING. 58-60
Amalgam Process 59
Immersion Process 59
Battery Process 59
Weigler's Process 60
Hern's Process 60
SECTION VII.
GALVANIZING. 61-66
INDEX. 67-69
HANDBOOK ON JAPANNING.
SECTION I.
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. Those Birmingham manufacturers who were the first to practise
japanning only on metals on which there was no need for a priming coat
did not of course adopt such a practice. Moreover, they found it
equally unnecessary in the case of papier-m�ch� and some other goods.
Hence Birmingham japanned goods wear better than those goods which
receive a priming previous to japanning.
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