Improvements in or relating to Producing a Gloss or Finish upon Articles of Wood or other similar Absorbent Material.
Year: 1891

page_text: Date of Application, 10th Nov., 1891-Accepted, 12th. Dec., 1891
COMPLETE SPECIFICATION.
Improvements in or relating to Producing a Gloss or Finish upon
Articles of Wood or other similar Absorbent Material.
A:communication by BYRON BENJAMIN GOLDSMITH, of No. 19 E. 74th Street,
in the City, County, and State of New York, United States of America,
Chemist.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, 'Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323, High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention has reference to a new method of producing a gloss or finish upon
articles of wood, or of other similar absorbent material, and while the same is more
especially adapted for finishing small articles, such as brush and umbrella handles,
smoking-pipe bowls, and other light, small and variously shaped articles, it is also
applicable to larger articles made of wood, or other absorbent material, such as
tables, chairs, book cases, and other kind of furniture.
Prior to this invention the production of the gloss or finish upon wooden articles
by varnish was attended by considerable difficulties, and uncertainty of result; it
required the exercise of trained judgment on the part of the operator, and
frequently the use of complicated machinery.
The general procedure in varnishing wooden surfaces and the phenomena
incidental thereto are as follows:
In a great number of cases the varnish is applied to the wooden surface before
the same has been particularly prepared for the reception of the varnish. In such
cases the first few coats of the varnishes in general use produce very 'little effect,
so far as the gloss is concerned; the reason for it being that the varnish is
absorbed by the wood, or as it is technically called, it sinks into the wood, very
little of it remaining on the surface. The appearance of the article at 'this stage
is rough and fibrous, generally dull, with small irregular patches, having a slight
gloss. The wood is, as a rule, considerably and irregularly darkened greatly
differing from the natural color of the wood, the peculiar ornamental characteristics
of which are thus obliterated or disfigured; the fibres are raised by the varnish
and give to the surface a woolly or cellular appearance. Any number of additional
coats of varnish which may now be applied, does not remedy this defect, since, while
by the same the gloss is heightened, the fibrous, woolly or cellular appearance is
only partly covered up, while the darkening of the wood cannot be remedied at all.
With a view, however, of rendering the appearance of the article smooth and the
gloss as uniform as possible, the article is, before the application of additional coats
of varnish, carefully smoothed either by pumice stone or by sand paper or by some
other abrading agent. After this, the additional coats of varnish remain practically
on the surface.and give to the article the high gloss required. As a rule the
sand-papering, or other abrading process has to be resorted to a number of 'times
between several layers of varnish, in order to secure the best results, and after the
final layer of varnish the latter is burnished or polished to secure the required
uniformity and brilliancy of gloss.
Thus it will be seen that by the old process of varnishing, a great number of
layers of ordinary varnish have to be applied, several sand-papering or other
abrading processes have to be resorted to, and hand or machine polishing has to be
practised in order to secure a high and uniform gloss; but notwithstanding all this,
the darkening of the natural color of the wood and therefore the obliteration of the

page_text: .
natural ornamental characteristics of the same cannot be avoided. By this old
process, during the drying of the first layers of varnish in heated chambers, there
is also observed the phenomenon which is known as the "foaming" of the varnish,
which is the exudation of air from the wood, and the evaporation of the solvent
from the first coats of varnish, and by which the outer varnish layers become more
or less blistered or honey-combed.
Sometimes the wood is prepared for the reception of the first coats of varnish
by the application of what is known as a wood filler, and such wood filler, while
it partly prevents the absorption of the varnish by the wood, and consequently
effects a slight saving of the amount of varnish used, does not prevent the raising
of the fibre.
In either case, however, a great number of coats of varnish must be used, and a
great number of sand-papering operations have to be gone through in order to
obtain the best results, and in most cases the final burnishing or polishing cannot
be dispensed with; and it is well known, that the highly ornamental effect of
genuine Japan work is due to the great number of varnishings and sand-paperings.
It will be readily understood that for cheap articles this practice is prohibitory on
account of the cost of the great amount of varnish consumed, and on account of
the great amount of skilled labour required.
It is the object of the present invention to overcome these difficulties and
objections, both as to the expense of the process and as to the results obtained;
and they are overcome and an exceedingly high gloss secured, and the natural
colour and grain of wooden articles preserved by producing, upon the wooden
surface, a skin of pyroxiline, or of a compound of pyroxiline with resin or resins,
before the varnish used for producing the gloss is applied; and such skin (which is
in the nature of, although not exactly, a wood filler) is produced by applying, upon
the wooden surfaces, one or more coats of a varnish containing pyroxiline, which,
when dry, leaves upon the surface of the wood an exceedingly thin and hard
transparent film of pyroxiline or pyroxiline compound, without raising the fibre,
without discolouring, and especially without darkening the wood. On the contrary,
the application of a varnish containing a sufficient quantity of pyroxiline, upon
wood, instead of raising the fibre, depresses the same during the drying of the
varnish and consequent contraction of the pyroxiline skin, so that, after the appli-
cation of a coat or coats of pyroxiline varnish, the surface of the wood is even
smoother than before the application of that varnish. In this condition, the
wood surface has no perceptible gloss, but appears to the eye nearly as dull,
and has exactly the same color, as before the varnishing. This last feature is
owing to the fact that pyroxiline does not sink into the wood, but remains
practically on the surface, protecting the same against the attack of other
varnishes, which may now be applied without in any way or manner disturbing
the fibre, which it cannot now reach.
The characteristic of pyroxiline in solution to remain on the surface of articles
of wood or of other absorbent material, that is to say, the characteristic not to
sink into the pores and not to raise the fibre has been found by experiment to be
a reality; the inventor has convinced himself of this by the fact that, when
perfectly dry, the coat of pyroxiline can be peeled off as a very smooth film,
while, if it had entered the pores, it could either not be peeled off at all, or, if
peeled off, it would necessarily be rough in appearance, since it would, in that
case, have followed and adapted itself to the irregularities of the pores.
It will now be understood that the first step in this novel process of varnishing
articles of wood or of other absorbent material is the application, upon the bare
surface of the wood, of a coat or coats of pyroxiline varnish; and, while the best
results are obtained by using varnish containing only pyroxiline dissolved in any
one of its known solvents, such as ether and alcohol or amyl acetate, or in benzine
and alcohol, it has been found that an addition of small quantities of resin does not
destroy the property of the pyroxiline to lay down the fibre, and in fact it adds a
little gloss, which, in the case of pyroxiline pure and simple, is almost imperceptible.

page_text: It will therefore be understood that, when speaking of pyroxiline varnish, varnishes
containing pyroxiline in considerable quantities are comprised by that term, nor is
the invention confined to the use of the solvents above enumerated. Thus, pyroxi-
line may be dissolved in alcohol and camphor, and other well known solvents may
be used.
The drying of the coat of pyroxiline varnish may be allowed to take place at
ordinary temperatures and without the use of artificially heated drying chambers,
and, the solvents used being highly volatile, the first coat or coats will be found to
be perfectly dry within a couple of hours.
The second step in the improved process is to apply upon the article one or more
coats of resin varnish, which is now absolutely prevented from sinking into the
wood, and flows upon the pyroxiline surface as upon metal, giving an exceedingly
high gloss to the article and adhering very tenaciously to the same since the
ordinary solvents of resin only very slightly attack the pyroxiline. Any ordinary
or preferred resin varnish may be used, and one or more coats of the same may be
applied without sand-papering or pumicing either the pyroxiline surface or any of
the superimposed layers of resin. A single coat of resin varnish gives very brilliant
effects, but one or more additional coats may be applied, whereby the gloss is
slightly heightened; in most cases, a single coat of resin varnish is all sufficient,
and it has been found that the base of pyroxiline prevents the escape of air from
the wood through the resin varnish, and, consequently, the formation of blisters
upon the same, even when it is dried at a comparatively high temperature.
If the process be stopped at this stage, the immediate results obtained are very
brilliant but the inventor has found, by experience, that articles, the exposed
surfaces of which are resin, become easily scratched and disfigured by handling,
and, when packed together for shipment and sale, in hot weather, the surfaces
become softened and frequently stick together, rendering the article unsaleable.
By reason of the softening of resin in hot weather, or when artificially heated,
as is the case with smoking-pipe bowls, or when the articles are used in heated
rooms, they receive and retain the impression of objects with which they come in
contact, and thus become dull and disfigured.
Another great disadvantage of an exposed resin surface is that it is injuriously
affected by the moisture, the carbonic acid and the ammonia of the atmosphere,
whereby most resins become partially saponified, so that, in course of time, the
surfaces become dull and unsightly, and even articles which are not ordinarily
handled, as stationary pieces of furniture, lose their gloss within a short time of
exposure, and have to be re-varnished, as is well known.
These defects are overcome by a third step of this process, which consists in
the application of a coat of pyroxiline varnish upon the resin varnish. By this,
the gloss of the resin varnish is not affected, and the hard outer skin of pyroxiline
effectually prevents scratching and sticking, and protects the resin from the
deteriorating effects of the atmosphere. It is preserved with its original brilliancy
between two impermeable skins of pyroxiline an indefinite time, both against
chemical attack from its absorbent base and from the atmosphere, and against
mechanical injury by handling.
By this improved process, therefore, the article receives upon its surface :-
First a layer or layers of pyroxiline;
Second a layer or layers of resin, and, if desirable;
Third a layer of pyroxiline.
The inventor is aware that pyroxiline varnish has been used for coating articles,
and, more especially, articles of metal; but, when used on wood or other absorbent
material, it was so used mainly for the purpose of waterproofing. Therefore the
coating of wooden articles with pyroxiline is not claimed, since this invention has
only reference to the preparation of such articles with pyroxiline or pyroxiline
compounds for the application thereto of further coats of a varnish containing
resin. One or more coats of pyroxiline directly applied upon wood, in order to
have a gloss, must be buffed and burnished, and this buffing and burnishing can be

page_text: dispensed with. It will, therefore, be understood that the high lustre of the
articles treated by this process is not due to the pyroxiline varnish by itself, but is
due to the resin varnish superimposed upon the pyroxiline varnish.
It has been explained above that the pyroxiline varnish used may contain a
slight admixture of resin, and it has been found that, similarly, the resin varnish
used may contain a slight admixture of pyroxiline. It is, therefore, within the
scope of the invention to coat wooden articles with varnishes.which.contain both
pyroxiline and resin, with this restriction, that the first varnish applied contains
more pyroxiline than resin, in order that the all important effect of compression of
the fibre be secured. The succeeding coats may then contain pyroxiline in
gradually diminishing proportions, and resin in gradually increasing proportions,
until the desired gloss is obtained. After this, a single coat of a varnish containing
pyroxiline alone, or containing pyroxiline in excess, may be applied; or, in place
of this, a number of succeeding coats with gradually increasing proportions of
pyroxiline may be used. All these changes and variations come within the scope
of the invention, the fundamental idea of which is to apply to the bare surface of
the wood a coat of varnish rich in pyroxiline, in order to lay down the fibre and
prevent the sinking into the wood of the superimposed layers of gloss-giving
varnish.
For the purposes of the invention, it is immaterial in what manner the variations
are applied; but it has been found that, with small articles, it is practicable and
advantageous to simply dip the article into the varnish.
If it be not desired to preserve the natural colour of the wood, the varnishes:can
be tinted or coloured with aniline or mineral colour, and, if it be desired to use
aniline dyes, the first pyroxiliue coat can be applied colourless, and, after the same
has dried, the article is immersed momentarily in an aniline dye, which colour.then
fixes.itself upon the pyroxiline.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to.me by
my foreign correspondent, I declare that what I claim is :-
1. The process of finishing articles of wood or other absorbent material which
consists in first producing upon the same a coat or coats of varnish containing
pyroxiline or pyroxiline compound; then producing upon this coat or coats a layer
or layers of varnish containing resin, and finally superimposing over the resin
varnish a layer of varnish containing pyroxiline or pyroxiline compound, sub-
stantially as described.
2. The process of finishing articles of wood, or other absorbent material which
consist in producing upon the same a series of coats of varnish containing gradually
diminished quantities of pyroxiline and gradually increased quantities of resin, and
finally superimposing upon these coats one or more coats of a varnish containing
pyroxiline in excess, substantially as described.
3. The use of pyroxiline and resin varnishes on wooden and other absorbent
articles for the production of a high and enduring gloss and for the preservation of
the natural color of the wood.
Dated this 9th day of November 1891.
WM. P. 'THOMPSON & Co.,
Agents 'for the Applicant.