Handbook on Japanning: 2nd Edition | Page 2

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-mâché and some other goods. Hence Birmingham japanned
goods wear better than those goods which receive a priming previous to

japanning.
PRIMING or PREPARING THE SURFACE TO BE JAPANNED.
The usual priming, where one is applied, consists of Paris white
(levigated whiting) made into a thin paste with size. The size should be
of a consistency between the common double size and glue, and mixed
with as much Paris white as will give it a good body so that it will hide
the surface on which it is applied. But in particular work glovers' or
parchment size instead of common size is used, and this is still further
improved by the addition of one-third of isinglass, and if the coat be not
applied too thickly it will be much less liable to peel or crack. The
surface should be previously prepared for this priming by being well
cleaned and by being brushed over with hot size diluted with two-thirds
of water, that is provided the size be of the usual strength. The priming
is then evenly and uniformly applied with a brush and left to dry. On a
fairly even surface two coats of priming properly applied should suffice.
But if it will not take a proper water polish, owing to the uneven
surface not being effectually filled up, one or more additional coats
must be applied. Previous to the last coat being applied, the surface
should be smoothed by fine glass paper. When the last coat of priming
is dry the water polish is applied. This is done by passing a fine wet rag
or moistened sponge over the surface until the whole appears uniformly
smooth and even. The priming is now complete and the surface ready
to take the japan ground or the coloured varnish.
THE FIRST STAGE IN THE JAPANNING OF WOOD OR OF
LEATHER WITHOUT A PRIMING.
[The leather is first securely stretched on a frame or board.] In this case,
that is when no priming coat is previously applied, the best way to
prepare the surface is to apply three