IMPROVEMENTS IN COMBINING TOGETHER SURFACES OF WOOD
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Samuel Drake at the Office of the
Commissioners of Patents, with his Petition, on the 13th February
1866.
I, SAMUEL DRAKE, of Auckland Street, Vauxhall, in the County of
Surrey, Engineer, do hereby declare the nature of the said Invention.
for." IMPROVEMENTS IN COMBINING TOGETHER SURFACES OF WOOD," to be as
follows:-
The improvements relate to combining together surfaces of wood so as
to obtain thereto greatly increased flexibility and strength, by which the
wood so combined may be more readily applied to various useful purposes,,
particularly where elasticity and strength or tenacity are required, as in
substitution of card or millboard. The wood to be combined is in the.
form of thin sheets, obtained by rending, as in obtaining what is called.
scale board, or by sawing, as in the case of veneers. Sheets of wood thus
obtained are saturated with size, by preference glue size, and heated. The
size used is contained in a trough of capacity sufficient for the sheets to
be treated, and each sheet as it is withdrawn from this trough is passed
between a pair of rollers, by which superfluous size is squeezed off, and at
the same time that which has been absorbed by the wood is thereby more...
completely forced into its pores. The sized sheets are then dried in
chambers which are gradually heated from a low to a high temperature,
taking care to keep the heat very gradual during the first part of the
drying process, until the size appears thoroughly absorbed and dry. I

page_text: then in like manner saturate the sheet or sheets which are to form the
central portion or interior of the combined sheets by immersion in a trough
of heated liquid glue, and in taking these sheets from this trough I placed
them in racks or cradles, suspended so that they may be readily turned, in
order that the glue may be uniformly distributed over the surfaces thereof.
This operation is conducted in a chamber heated to a low temperature,
and when the glue on such sheets or surfaces is set I apply to each surface
thereof a sheet prepared as stated, by sizing, only taking care that the
direction of the grain of the intermediate pieces is transverse or diagonal
to those next adjoining or outside. The combined sheets are then placed
between hot plates, which, or the surfaces thereof in contact with the wood,
I prefer to be of zinc, as thereby I obtain a finer pressing surface, and less
tendency to discolor light woods. I allow the combined sheets to remain
for a considerable time between these heated surfaces under pressure.
Five hours I have found to answer well. When removed from between
these plates and the pressure I place the combined sheets in racks or
cradles to hold them from winding, and so that currents of hot air may
freely pass around them. I prefer that thickness be given to the central
sheet to bring it with the thin outer sheets to the desired thickness. When
mortice holes,, or holes in a direction from one to the opposite edge of the
sheets are required, such are obtained by the omission of the central sheet
or portions thereof at those parts; the outer surface of these combined
sheets may be polished if desired. The glue used I prefer to have mixed
with it a small proportion of spirits of salts, say, two drachms of spirits of salts
to two quarts of liquid glue, but this proportion may be varied. In some
cases, in place of or in addition to wood for the interior surface, I employ
canvas or other cloth treated as described in relation to wood. This
material, when used as a substitute for millboard, has considerable advan-
tages over that material, inasmuch as it can be produced in a finished state
at a less cost than millboard, and renders the expensive process of covering
with paper, cloth, or leather unnecessary. It is also admirably adapted for
perforation, a quality which renders it easy of simple yet elaborate orna-
mentation which may be carried to the extreme edge without fracture.
When prepared between zinc or other metal plates, planing will rarely be
found necessary to give it a smooth surface.