Improvements in the Manufacture of Artificial Marble.
Year: 1892

page_text: Date of Application, 1st Jan., 1892
Complete Specification Left, 29th Oct., 1892-Accepted, 3rd Dec., 1.892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Artificial Marble.
I PIERRE AIGNAU MOREAU, of Meung-sur-Loire, Loiret, in the Republic of
France, Marble Workman, do hereby declare the nature of this invention to be
as follows:-
This invention relates to improvements in the manufacture of artificial marble
and consists in working and sculping white soft porous stones in such a manner as
to bring them to the desired form of the object to be fashioned and then to trans-
form the stones so formed into marble.
This transformation of the soft stones into marble is effected in two operations,
that is to say, the first is the dyeing of the stone or, properly speaking, the
application thereto of colored stains of varied colour and appearance and which
penetrate the stone. The second is the hardening of the stones so colored.
The dye baths have for a base the sulphates of copper, of iron, of zinc, &c.,
which are dissolved to saturation separately in water, either hot or cold, by
preference at about 25° to 30°.
To colour the stone a colored spirit-varnish is prepared with Prussian red (rouge
de Prusse) or with another color, or with one of the coloring baths above described.
The varnish is dropped onto clear water contained in a vessel and forms on the
surface of the water marbling, veins, blended spots, variously coloured which may
be modified as desired by means of a wooden rod. The worked white stone is
then placed to take the colour; the stone is turned and its several faces dipped in
order that they may all be equally coloured. To obtain fine colored veins there is
dropped on the clear water in the vessel a small quantity of coloured varnish
which divides on the water; soap suds are then projected drop by drop on the
varnish and these drops split up the varnish whereby I obtain irregular fine lines
similar to the veins in natural marble.
In some cases in order to colour the stone I make use of a sponge soaked with
colour which is applied quickly and at random.
After being colored the stone is steeped in a bath of sulphate; as the varnish is
not dry the sulphate and the colours penetrate to a greater or less extent into the
mass of the stone and as some parts dry quicker than others I obtain varieties of
tinting or clouding.
The stones thus printed or marbled are then hardened by soaking in a metallic
bath, a saturated solution of sulphate of zinc by preference, at a temperature
varying from 25° to 50°.
For fixing the colours I have found it advantageous to soak the stones in warm
water at 60° to 70°.
These artificial marbles are polished in the same manner as natural marbles;
the polishing is rendered easier, quicker and more durable by providing the brush
with one or two layers of oil varnish or spirit varnish.
Dated the 1st day of January 1892.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Artificial Marble.
I, PIERRE AIGNAU MOREAU, of Meung-sur-Loire, Loiret, in the Republic of
France, Marble Workman, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to improvements in the manufacture of artificial marble.
According to my invention I employ white soft porous stones, such as chalk,
Portland stone, or other natural or artificial stone which is sufficiently porous.
These stones may be worked or sculped in such a manner as to bring them to the
desired form of the object to be fashioned whether in the form or approximately
in the form of a finished article or in the form of blocks, and then to transform
the stones so formed into artificial marble.
This transformation of the sofs stones is effected in two operations, that is to say,
the first is the dyeing of the stone or, properly speaking, the application thereto
of coloured stains of varied colour and appearance which penetrate the stone. The
second is the hardening of the stones so coloured.
The dye baths have for a base the sulphates of copper, of iron, of zinc, etc.,
which are dissolved separately in water, either hot or cold, by preference at about
25° to 30° C. The solutions should be about of a strength measured by 20 to
35 degrees on the Beaumé hydrometer according to the depth of colouring
required.
Before colouring the stone a coloured spirit-varnish is prepared with Prussian
red (rouge de Prusse) or other suitable colour, the purpose of the coloured varnish
being simply to serve as a protective coating to the requisite portions of the
stone. This varnish is dropped onto clear water contained in a vessel and forms
on the surface of the water marbling, veins, blended spots, irregularly arranged
which may be modified as desired by means of a wooden rod. The worked white
stone, after being dried by exposure under cover to a current of air for a few
days, or by artificially heated air, is then applied to the surface of the water to
take the colour. The stone is turned and its several faces dipped in order that
they may all be equally coloured. To obtain finely divided veins there may be
dropped on the clear water in the vessel a small quantity of coloured varnish
which divides on the water, and soap suds may be projected drop by drop on the
varnish so that these drops may split up the varnish. By this means may obtain
irregular fine lines similar to the veins in natural marble..
In some cases in order to coat the stone in the requisite parts with the varnish I
make use of a sponge soaked with colour which is applied quickly and at random,
or the varnish may be applied in any other suitable way.
After being thus treated the stone is steeped in a bath of sulphate. Where the
stone is uncoated or where the varnish is not dry the colour baths penetrate to a
greater or less extent into the mass of the stone. If the varnish is not allowed to
dry completely, then as some parts dry quicker than others I obtain varieties of
tinting or clouding. The different colour baths may be used successively in various
orders in order to give varied results.
After immersion in the colour baths the coating of varnish may be removed by
pumice stone or otherwise, and the stone is then steeped in a warm bath for half
an hour, (or more if the stone be more hard) in order to fix and develop the
colour.
For softer stones the temperature of this bath may be about 50° C., rising to
100° C. in the case of harder stones.
The above described process of colouring or dyeing the stone is more fully
described in the Complete Specification of an application for Letters Patent
numbered 19395 dated October 28th 1892 for "Improvements in the production of
5°

page_text: ornamental stones artificially coloured." This Complete Specification has been
already filed with such application, and I refer to such Specification for a more
detailed statement of the method of colouring which may be employed and the
modifications and variations of which the process of colouring permits. In this
present Specification I make no claim separately to the method of coloration,
because such method was in some respects incorrectly described in my Provisional
Specification and I have therefore taken the precaution of applying for a separate
Patent in respect of such method and of excluding from this present Specification
any claim to the mere colouring process.
After the stone has been treated as above mentioned or (if it is desired to produce
a plain marble without veining) after the stone has been coloured uniformly in any
suitable manner, or without any coloration whatever if none is required, the stone
is submitted to a drying process before immersion in the hardening bath. This I
prefer to do by placing the stone on a grid in a current of hot air of a temperature
of from 40° C. to 100° C. warmed by a heated flue beneath.
When the stone has been thoroughly dried it is hardened by soaking in a bath
consisting of a solution of sulphate of zinc of a strength of about 35 to 50 degrees
measured by the Beaumé hydrometer.
In order that the hardening process may thoroughly penetrate the interior of the
stone I remove the stone from the hardening bath after an immersion of, say, half
an hour and place it again for an hour in the hot water bath and dry it again on
the grid. If this precaution is not taken the surface of the stone becomes
hardened and prevents the hardening bath from having its proper effect upon the
interior.
After this the stone is again placed in the hardening bath for a period of
say 24 hours.
If the interior hardening is of no consequence it is unnecessary to interrupt the
hardening process by immersion in the hot bath, and the stone may be left for the
full period in the hardening bath.
The time required for hardening varies very much according to the nature and
thickness of the stone. For instance, for chalk slabs of about an inch and a
quarter in thickness, requiring to be hardened throughout, the periods above men-
tioned will suffice. For greater thicknesses the preliminary hardening may be
increased in duration and the final immersion may be increased to 48 hours
or more.
In some cases with very thick stones, I find it advantageous to place the stone
first in the hardening bath for say as much as two hours, and then to place the
stone for one or two hours in a cold bath, to assist the penetration into the interior,
before placing the block for an hour in the hot bath. It is then dried and replaced
in the hardening bath.
For slabs of Portland stone the time of the preliminary hardening may be
increased still more, say to 4 hours, and the final treatment in the hardening bath
to 48 hours.
The process of taking the stone from the hardening bath, immersing it in hot
water, drying and re-immersing in the hardening bath may be repeated with
advantage in some cases, where interior hardness is desired, as also may the alter-
native process for thicker stones of hardening, cold bath, hot bath, drying and
re-immersing.
After hardening the stone may be worked and polished in the same way as
natural marble.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. The method of manufacturing artificial marble from white porous stones, such
for instance as chalk, Portland stone or Bath stone, by hardening such stones
substantially in the manner hereinbefore described.

page_text: 2. Treating porous stones such as above mentioned after they have been coloured
in the manner, hereinbefore described or referred to, or in any equivalent way, by
the method of drying and immersing in a bath of sulphate of zinc substantially as
above described.
3. Hardening porous stones such as above mentioned interiorly by alternations
of hardening bath, hot water bath and drying repeated if necessary substantially
as herein before described.
4. Hardening porous stones such as above mentioned interiorly by alternations
of hardening bath, cold bath, hot bath and drying, repeated if necessary, sub-
stantially as hereinbefore described.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.