Manufacture of Compound Plates or Slabs of Cement, Plaster, and like Material.
Year: 1890

page_text: Date of Application, 28th July, 1890
Complete Specification Left, 15th Apr. 1891-Accepted, 16th May, 1891
PROVISIONAL SPECIFICATION.
Manufacture of Compound Plates or Slabs of Cement, Plaster, and
like Material.
I, EMILE DUPONT of Brussels, Belgium, Engineer do hereby declare the nature
of this invention to be as follows:-
My invention has for its object, an improved manufacture of plates of cement
plaster and like plastic material whereby, while the said material itself is kept
thin, the plates are made to possess great rigidity and offer considerable resistance
to flexure.
The invention consists essentially in combining, according to the strength
required, one or more layers of plaster or cement with one or more thin
supporting plates, formning together a plate or slab of small thickness but of
great strength, such plates being applicable to all building purposes. For various
reasons the nature of the plates to be combined with the plaster or cement is not
indifferent, and practically there is only a single material that can be employed
with full advantage for this purpose.
The points which determine the use of a special material are more particularly
the questions of strength, solidity, weight, economy, and of the assimilability of the
support to the plaster or cement. The material constituting the support of which
the combination with the plaster or cement constitutes more particularly the
essential feature of my invention, is paper, or paper pulp, worked into various forms
such as papier maché, card board, or mill board. As a matter of fact strong card
board or mill board, of equal thickness with wood boards, is of greater strength
than these, and is lighter than metal, while at the same time it is less expensive
than either, and is capable of uniting perfectly with the plaster, or cement and at
the same time it permanently retains its dimensions, while other materials expand
and contract to an extent which prevents any permanent combination with the
plaster or material.
The said compound plates can be employed either for internal or external work
in building, according to the nature of the plastic material employed. If for
example plaster of paris or like plaster be used, very light plates or slabs are
produced, suitable for internal work. The manufacture of the plates is of a very
simple nature; it consists in spreading upon one or both surfaces of the mill board
or card board support a coating of plaster, after which the whole is subject to
suitable pressure in a mould between two polished plates of metal, marble or other
material. The surfaces of the compound plate after desiccation will be of so smooth
and fine an appearance as to be similar to polished alabaster.
During the operation the plaster is partly absorbed by the pores of the mill
board whereby it is made to adhere to the latter and to impart to it the rigidity of
the plaster itself. For increasing the adhesion, the supporting material may be
perforated with small holes at suitable distances apart, through which the plastic
material passes, thereby combining the layers on each side together.
According to another arrangement the mill board may have projecting metal or
wood pins driven into or through it, so that on applying the plaster, this will
penetrate between the pins and be securely held thereby. Plates so prepared can
be secured upon frame-work or other supports by screws, nails bolts or other
means, like ordinary boards, and may serve as coverings for walls, partitions & c.
Nails may be driven into the plates for fixing objects thereto, as they will hold
effectually when they penetrate the mill board or card board.
When manufacturing such plates for external work, the only difference consists in
replacing the plaster by cement. Plates impermeable to water and other liquids are
1

page_text: thus obtained, which can be used with advantage as an external covering for the
walls of buildings, roofs, cisterns, reservoirs conduits &c.
The plates can be ornamented at will with mouldings or other designs, according
to the purposes to which they are to be employed, and they may be made of any
desired configuration and be either flat, concave, convex curved or undulated.
On the accompanying drawing are shewn by way of example some of the modes
of making such plates.
Fig. 1 shews a section of a plate consisting merely of a middle layer of mill board
&c. Between two layers of plaster or cement, without any auxiliary means for
combining them ;
Fig. 2 shews a section in which the mill board &c. is perforated so that the
plaster or cement while in a plastic state will penetrate through the same and thus
unite the two outer layers;
Fig. 3 shews a plan of the mill board support.
Fig. 4 shews a section in which pins or studs are driven through into the mill
board so as to serve as a key for the plaster or cement.
Fig. 5 shews a modification in which there are two layers of millboard &c. between
three layers of plaster or cement.
The thickness of the plaster or cement layers may of course vary, but they are
generally made to correspond with the thickness of the mill board &c., or they may
even be thinner than this, according to circumstances.
Dated this 28th day of July 1890.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of Compound Plates or Slabs of Cement, Plaster, and
like Material.
1, EMILE DUPONT, of 45 Rue Albert de la Tour Brussels, Belgium, Engineer,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement-
My invention has for its object an improved manufacture of plates of cement,
plaster and like plastic material whereby, while the said material itself is kept
thin, the plates are made to possess great rigidity and offer considerable resistance
to flexure.
The invention consists essentially in combining according to the strength required,
one or more layers of plaster or cement with one or more thin supporting plates,
forming together a plate or slab of small thickness but of great strength, such plates
being applicable to all building purposes.
For various reasons the nature of the plates to be combined with the plaster or
cement is not indifferent, and practically there is only a single material that can be
employed with full advantage for this purpose.
The points which determine the use of a special material are more particularly
the questions of strength, solidity, weight, economy, and of the assimilability of the
support to the plaster or cement. The material constituting the support, of which
the combination with the plaster or cement constitutes more particularly the essential
feature of my invention, is paper, or paper pulp, worked into various forms such as
papier maché, card board, or mill board. As a matter of fact strong card board or
mill board, of equal thickness with wood boards, is of greater strength than these,
and is lighter than metal, while at the same time it is less expensive than either, and
is capable of uniting perfectly with the plaster or cement and at the same time it
permanently retains its dimensions, while other materials expand and contract
to an extent which prevents any permanent combination with the plaster or
material.
The said compound plates can be employed either for internal or external work

page_text: If for
in building, according to the nature of the plastic material employed.
example plaster of paris or like plaster be used, very light plates or slabs are
produced, suitable for internal work. The manufacture of the plates is of a very
simple nature it consists in spreading upon one or both surfaces of the mill board
or card board support a coating of plaster, after which the whole is subjected to
suitable pressure in a mould between two polished plates of metal, marble or other
material. The surfaces of the compound plate after desiccation will be of so smooth
and fine an appearance as to be similar to polished alabaster.
During the operation the plaster is partly absorbed by the pores of the mill
board whereby it is made to adhere to the latter and to impart to it the rigidity of
the plaster itself. For increasing the adhesion, the supporting material may be
perforated with small holes at suitable distances apart, through which the plastic
material passes, thereby combining the layers on each side together.
According to another arrangement the mill board may have projecting metal or
wood pins driven into or through it, so that on applying the plaster, this will
penetrate between the pins and be securely held thereby. Plates so prepared can
be secured upon framework or other supports by screws nails bolts or other means
like ordinary boards, and may serve as coverings for walls, partitions &c.
Nails may be driven into the plates for fixing objects thereto as they will hold
effectually when they penetrate the mill board or card board.
When manufacturing such plates for external work, the only difference consists
in replacing the plaster by cement. Plates impermeable to water and other liquids
are thus obtained, which can be used with advantage, as an external covering for
the walls of buildings, roofs, cisterns, reservoirs, conduits &c.
The plates can be ornamented at will with mouldings or other designs, according
to the purposes to which they are to be employed, and they may be made of any
desired configuration, and be either flat, concave, convex, curved or undulated.
On the drawing accompanying my Provisional Specification are shewn by way of
example some of the modes of making such plates.
Fig. 1 shews a section of a plate consisting merely of a middle layer of mill board
&c., between two layers of plaster or cement, without any auxiliary means for
combining them :
Fig. 2 shews a section in which the mill board &c. is perforated so that the
plaster or cement while in a plastic state will penetrate through the same and thus
unite the two outer layers;
Fig. 3 shews a plan of the mill board support,
Fig. 4 shews a section in which pins or studs are driven through or into the mill-
board so as to serve as a key for the plaster or cement.
Fig. 5 shews a modification in which there are two layers of mill board &c.
between three layers of plaster or cement.
The thickness of the plaster or cement layers may of course vary, but they are
generally made to correspond with the thickness of the mill board &c. or they may
even be thinner than this, according to circumstances.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is :-
The manufacture of thin light and strong plates or slabs of plaster, cement, or the
like, by uniting one or more layers of plaster, cement, and the like, with one or
more layers of cardboard or mill board, to which the plaster or cement is made to
adhere either by simple absorption or compression, or by perforation of the card
board or by forming projections thereon, substantially as described with reference
to the drawings.
ABEL & IMRAY,
Agents for the Applicant.