IMPROVEMENTS IN PRODUCING DESIGNS OR FIGURES ON OR IN WOOD IN IMITATION OF CARVED WORK, AND IN MEANS OR APPARATUS EMPLOYED IN CONNECTION THEREWITH."
Year: 1880

page_text: LETTERS PATENT to Augusto Guattari, of Paris, in the Republic of France,
and temporarily of Chancery Lane, in the County of Middlesex, for an
Invention of "IMPROVEMENTS IN PRODUCING DESIGNS OR FIGURES ON OR IN
WOOD IN IMITATION OF CARVED WORK, AND IN MEANS OR APPARATUS
EMPLOYED IN CONNECTION THEREWITH."
PROVISIONAL SPECIFICATION left by the said Augusto Guattari at the
Office of the Commissioners of Patents on the 31st December 1880.
AUGUSTO GUATTARI, of Paris, in the Republic of France, and temporarily of
Chancery Lane, in the County. of Middlesex. "IMPROVEMENTS IN PRODUCING
DESIGNS OR FIGURES ON OR IN WOOD IN IMITATION OF CARVED WORK, AND
IN MEANS OR APPARATUS EMPLOYED IN CONNECTION THEREWITH.
My Invention relates, first, to improvements in the process of producing figures
or designs in or on wood, in high or low relief or otherwise, in imitation of carved
work, by the combined action of heat and pressure applied by heated metal moulds,
whereby the portions of the wood to be removed are charred or burnt away, as
described in the Specification of a Patent granted to Alexander Melville Clark,
dated March 1st, 1878, No. 843; and, secondly, to improvements in the moulds
and other means or apparatus used in connection with the said process.
Experience has shown that if the mould is too hot at the commencement of the
operation (especially if the smoke vents with which it is furnished are insufficient),
the sap of the wood instead of being vaporised and escaping freely becomes tarry,
and forms with the carbonized fibres of the wood a black and tenaceous crust
adhering to the surface of the wood, and which by obstructing the transmission of
the heat of the mould retards the charring or burning away of the wood beneath.
it. Hence it is necessary to maintain the pressure of the hot mould for a longer
time, and consequently the details of the design most in relief which enter farthest
into the hollows of the mould are too much burnt and the finished work is not so
sharp and durable at these parts of the design as it should be.
I have found that to produce the best results, especially when it is required to

page_text: -
execute work in high relief, in which the hollows of the design are proportionately
deep, it is desirable to graduate not only the pressure as stated in the aforesaid
Patent, but also the heat of the mould by employing for each successive application
of the mould successively higher degrees of heat and pressure.
It is also important to provide the mould with vents so arranged as to permit
the free escape from all parts of the mould of the vaporised moisture of the wood
as fast as it is evolved by the heat, so as to avoid injury to the details of the
design.
In practice, to economise time and heat, it is preferable to roughly cut out the
deepest hollows of the design with a gouge or other hand tool, in order to leave
less wood to be charred or burnt away. This done, the process of charring is
performed as follows to obtain the best results :-
The cast iron mould, which is the counterpart of the subject to be reproduced on
the wood, is heated in a furnace so constructed that the heat can be easily regulated,
and provided with means for the introduction of a pyrometer, by which the heat
of the moulds in the furnace can be readily ascertained. The proper degree of heat
for the mould depends upon the nature of the wood operated on, the height of the
relief, and consequently the number of pressures of the heated mould necessary for
the perfect execution of the work. For instance, for walnut, pear tree wood, or
other hard wood (which it is preferable to employ), the heat of the mould at the
first pressure or time of application to the wood, should be about 900° F., and should
be increased progressively for each such successive pressure or application to 1450° F.
at the last or finishing pressure.
The number of pressures or applications of the mould will necessarily vary
according to the height of the relief to be produced. For small designs in low
relief, or figures in which the hollows are shallow, a single pressure may suffice,
while for larger subjects in higher relief, four or six successive pressures or
applications of the heated mould are generally sufficient.
The pressure of the mould should not be continued beyond a certain limit of
time, which limit depends on the nature of the wood, the heat of the mould, and
the height of the relief, and other circumstances. For the initial pressure about
15 seconds are usually sufficient, the length of time being gradually diminished at
each successive pressure down to about 2 seconds for the final or finishing pressure.
The degree of pressure with which the mould is applied should be progressively
more powerful at each successive pressure, the degree of power being regulated by
opening more or less the valve or cock that controls the communication between
the accumulator and the cylinder of the hydraulic press in which pressure is
effected, the said valve or cock being furnished with an index and dial to show
the extent to which it is opened.
The degree of pressure depends on the nature of the wood operated on on the
area of the mould, and also on the height of the relief to be produced.
For operating on hard wood, and supposing the mould to be about 40 inches
long, 20 inches wide, and 6 inches deep, the power developed by the press should
be about 100 tons for the first pressure, in order to burn away most of the useless
portions of the wood. For the second pressure the power developed should com-
mence at about 60 tons, and gradually increase to about 80 tons before the pressure
is removed. For the third and following pressures the power developed should
cominence each time at about 60 tons, and gradually increase to 100 tons before
the pressure is removed.
For designs in low relief (say from 1/2 inch to 1/2 inches), a single pressure is
generally sufficient, but in this case the power should be gradually increased from
about 60 tons to 80 tons, and the temperature of the mould should be about
1200° F.
The cast iron mould should have vent holes cast through it, in number depending
on the size of the mould and the nature of the design. These boles communicate
with the interior or hollow of the mould, generally at the deepest parts thereof, o
at other convenient points, so as not to interfere with the design. These vent

page_text: holes are directed generally towards the back of the mould, where they com-
municate with transverse channels or grooves leading out at the sides and ends of
the moulds, in order to permit of the free escape of the vaporised moisture and gases
from between the back of the mould and the follower of the press on which it
rests. The vent holes are of conical form, and communicate with the interior of
the mould by their smaller, and with the transverse channels at back by their
larger ends, so that the impressions left on the work by the holes shall be as small
as possible, and so as to permit the gases and bituminous vapors to escape freely
and without liability to choke the vents.
By the employment of moulds furnished with vents thus arranged I obtain more
perfect and delicately executed work, the surface of which is not permanently
blackened or carbonised, as the bituminous matters escape freely instead of becoming
absorbed in the surface of the wood.
It is necessary to clean the mould after each application and on taking it from
the furnace, and for this purpose I employ a jet of air, compressed to about 2 to
4 atmospheres, which is projected into the hollows of the mould.
The furnace for heating the moulds is reverberatory, and is furnished with hit
and miss gratings, or other means of readily regulating the draught, whereby the
temperature of all parts of the furnace can be equalised and regulated as required.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Augusto Guattari in the Great Seal Patent Office on the 30th June
1881.
AUGUSTO GUATTARI, of Paris, in the Republic of France, and temporarily of
Chancery Lane, in the County of Middlesex. "IMPROVEMENTS IN PRODUCING
DESIGNS OR FIGURES ON OR IN WOOD IN IMITATION OF CARVED WORK, AND
IN MEANS OR APPARATUS EMPLOYED IN CONNECTION THEREWITH."
My Invention relates, first, to improvements in the process of producing figures
or designs in or on wood in high or low relief, or otherwise, in imitation of carved
work, by the combined action of heat and pressure applied by heated metal moulds,
whereby the portions of the wood to be removed are charred or burnt away, as
described in the Specification of a Patent granted to Alexander Melville Clark,
dated March 1st, 1878, No. 843; and, secondly, to improvements in the moulds
used in connection with the said process.
Experience has since shown that if the mould be too hot at the commencement
of the operation (especially if the smoke vents with which it is furnished are
insufficient), the sap of the wood instead of being vaporised and escaping freely
becomes tarry, and forms with the carbonised fibres of the wood a black and
tenaceous crust, adhering to the surface of the wood, and which by obstructing the
transmission of the heat of the mould retards the charring or burning away of the

page_text: wood beneath it. Hence it is necessary to maintain the pressure of the hot mould
for a longer time, and consequently the details of the design most in relief which
enter farthest into the hollows of the mould are too much burnt, and the finished
work is not so sharp and durable at these parts of the design as it should be.
I have found that to produce the best results, especially when it is required to
execute work in high relief in which the hollows of the design are proportionately
deep, it is desirable to graduate not only the pressure, as stated in the aforesaid
Patent, but also to graduate the heat of the mould by employing for each successive
application of the mould successively higher degrees of heat and pressure for pro-
gressively shorter durations of time. It is also important to provide the mould
with vents, so arranged as to permit the free escape from all parts of the mould of
the vaporised moisture of the wood as fast as it is evolved by the heat, so as to
avoid injury to the details of the design. In practise, to economise time and heat,
it is preferable to roughly cut out the deepest hollows of the design with a gouge
or other hand tool in order to leave less wood to be charred or burnt away. This
done the process of charring is performed as follows to obtain the best results:-
The cast iron mould, which is the counterpart of the subject to be reproduced on
the wood, is heated in a furnace so constructed that the heat can be easily regulated
and provided with means for the introduction of a pyrometer by which the heat of
the moulds in the furnace can be readily ascertained. The proper degree of heat
for the mould depends upon the nature of the wood operated on, the height of the
relief, and consequently the number of pressures of the heated mould necessary for
the perfect execution of the work. For instance, for walnut, pear tree wood, or
other hard wood (which it is preferable to employ), the heat of the mould at the
first pressure or time of application to the wood should be about 900° F., and
should be increased progressively for each successive pressure or application of the
mould to 1450° F. at the last or finishing pressure. The mould must therefore be
reheated in the furnace after each pressure.
The number of pressures or applications of the mould will necessarily vary
according to the height of the relief to be produced. For small designs in low
relief, or figures in which the hollows are shallow, a single pressure may suffice,
while for larger subjects in higher relief, four or six successive pressures or
applications of the heated mould are generally sufficient.
The pressure of the mould should not be continued beyond a certain limit of
time, which limit depends on the nature of the wood, the heat of the mould, and
the height of the relief, and other circumstances. For the initial pressure about
15 seconds are usually sufficient, the length of time being gradually diminished at
each successive pressure down to about 2 seconds for the final or finishing pressure.
The degree of pressure with which the mould is applied should be progressively
more powerful at each successive pressure, the degree of power being regulated by
opening more or less the valve or cock that controls the communication between
the accumulator and the cylinder of the hydraulic press in which pressure is
effected, the said valve or cock being furnished with an index and dial to show the
extent to which it is opened. The degree of pressure depends on the nature of the
wood operated on, on the area of the mould, and also on the height of the relief to
be produced. For operating on hard wood, and supposing the mould to be about
40 inches long, 20 inches wide, and 6 inches deep, the pressure applied by the
press should be from 100 tons to 160 tons for the first pressure (equal to about
280 lbs. to 450 lbs. per square inch of area of the mould) in order to burn away
most of the useless portions of the wood. The second pressure should commence at
about 60 tons and gradually increase to about 80 tons before the pressure is removed.
The third and following pressures should commence each time at about 60 tons
and gradually increase to 100 tons before the pressure is removed. For designs in
low relief (say from 1/2 inch to 1%, inches) a single pressure is generally sufficient,
but in this case it should be gradually increased from about 60 tons to 80 tons,
and the temperature of the mould should be about 1200° F. The cast iron mould
should have vent holes cast through it, in number depending on the size of the

page_text: Figure 1 is an elevation, and Figure 2 a sectional plan of a couvenient arrange-
ment of furnace for heating the moulds. It is constructed of firebrick enclosed in
cast iron plates tied together longitudinally and transversely by tie bolts. A, A,
are the two fire places from which the products of combustion pass into two
reverberatory arches B, indicated by dotted lines in Figure 1, closed at both ends
by doors C. C. D are longitudinal iron bars upon which the moulds are placed to
be heated. E, E, are two flues leading downwards to the stack, and with which
the two arches respectively communicate by means of apertures F controlled by
dampers formed of sliding plates G, drawing out at the opposite sides of the
furnace, and having apertures so arranged with regard to those F, that by drawing
out the plates G more or less, as indicated by a scale upon the plates, the
apertures F may be opened more or less, except the two middle ones, which are
generally kept closed, in order that all parts of the arch may be equally heated.
The doors C are fitted to slide up and down in guides on the walls of the furnace,
and are hung from counterbalanced levers so as to be quickly and easily opened
and closed. Each door C has an oblong hole in it, shown by dotted lines in
Figure 1, covered by a plate c fitted to slide up and down in vertical guides on the
door, and this plate has a tubular guide c¹ closed by a pivoted cover. This guide c¹
is of a size to receive a pyrometer of suitable construction which is passed through
it and through the oblong hole before mentioned, and applied upon the moulds in
the furnace to ascertain their temperature, the oblong form of the said hole and the
movability of the guide enabling the pyrometer to be applied upon moulds of
different thicknesses. The moulds are readily pushed or drawn in or out along the
bars D, and on being removed from the furnace are received upon a truck running
on a railway before each front of the furnace by which they are conveyed to the
press, the truck corresponding in height to the level of the bars D, and of the
follower of the press when in its lowest position, so that the moulds may be quickly
transferred from the one to the other as required. Figure 3 is a section, and
Figure 4 a back or underside view of a mould, such as I employ. It is made of
cast iron cast in a sand, plaster, or copper mould obtained from a plaster model.
H is the cavity of any desired form, according to the design to be produced, and of
which it is the counterpart. I are the conical vent holes communicating with the
deepest parts of the cavity H by their smaller ends, and opening at their larger

page_text: 20
ths.
ends into the cross grooves or channels K running across the back of the mould
from side to side and end to end for the escape of the gases, those nearest the ends
and sides opening directly therethrough as shown. These vent holes should not be
larger than 30th of an inch diameter at their smaller ends, and about 3/the. of an
inch at their larger ends, the channels K into which they open being half round,
and about an inch or more in width. Moulds of ordinary size are about
20 inches to 30 inches in length, by 15 inches to 22 inches in width, and 4 inches
thick, but they may be as much as 40 inches long by 25 inches wide if preferred,
and thicker in proportion.
2
a
In order to control and regulate accurately the action of the press, a screw down
valve is employed to control the supply of water from the accumulator to the press,
said valve being worked by a hand wheel, having an index working over
graduated plate. To control the exhaust from the press a similar valve is used, and
when opened the water should escape quickly to permit of the press descending,
and the mould and work being rapidly removed after the pressure has been
applied.
The construction of the press requires no description, being an ordinary hydro-
static press worked by an accumulator of sufficient power in the usual way. The
heated mould is placed face uppermost upon the follower of the press, and upon
the mould is placed the wood to be ornamented, a cushion of wood being placed if
necessary upon the latter to come against the head of the press, and ensure an even
distribution of the pressure.
Having described the nature of my Invention, and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the herein-
before in part recited Letters Patent is,
1st. The improved process herein described of producing figures or designs in or
on wood in imitation of carved work by the combined action of heat and pressure
applied by means of metal moulds, such as herein described, both the heat and the
pressure being graduated or increased and applied for progressively shorter periods
of time at each successive application of the mould, substantially in the manner
and for the purpose herein set forth.
2nd. The employment in and for the purposes of the herein described process of
metal moulds constructed with conical vent holes, and with grooves or channels at
back, into which the vent holes lead from the cavity of the mould, substantially as
herein described and shown in the Drawing.
In witness whereof, I, the said Augusto Guattari, have hereunto set my band
and seal, this Twenty ninth day of June, A.D. 1881.
Witness,
W. CLARK,
53, Chancery Lane,
Patent Agent.
AUGº. GUATTARI. (L.S.)