IMPROVEMENTS IN THE . MANUFACTURE OF ARTIFICIAL STONE AND CEMENT.
Year: 1883

page_text: LETTERS PATENT to Edward Sanger Shepherd, of Warwick Road, Paddington
in the County of Middlesex and James Leigh Aspinwall of the New Vronheulog
Slate Company Limited, Nantlle Vale in the County of Carnarvon for an
PROVISIONAL SPECIFICATION left by the said Edward Sanger Shepherd and
James Leigh Aspinwall at the Office of the Commissioners of Patents on the
9th May 1883.
EDWARD SANGER SHEPHERD of Warwick Road, Paddington, in the County of
Middlesex and JAMES LEIGH ASPINWALL of the New Vronheulog Slate Company
Limited Nantlle Vale in the County of Carnarvon "IMPROVEMENTS IN THE
.
MANUFACTURE OF ARTIFICIAL STONE AND CEMENT.
"
Our invention relates to the utilization of slate in the manufacture of artificial
stone and cement.
In the operation of quarrying slate there has hitherto been a large amount of
waste in some cases as much as ten tons being wasted in the production of one ton
of marketable slate.
The chief object of our said invention is to utilize this waste
Various materials have hitherto been used for making artificial stone, such as
coarse sand, comminuted granite, or the like. It is requisite in all such cases to
have an aggregate sufficiently rough, and at the same time porous and capable of
forming a thoroughly coherent mass, when mixed with Portland or other cement
We have discovered that slate answers all these purposes and we use slate debris
in the manufacture of artificial stone instead of the sand or granite hitherto used.
According to this part of our said invention we first reduce the slate and free it
from the dust, the portland or other cement is now added, and a hardening solution
is then added to the loose mass instead of, as has heretofore been the practice,
mixing the mass with water, and after it had been allowed to set immersing the
moulded stone into the hardening solution. In this manner the stone is acted upon
entirely, instead of upon the surface only as was formerly the case.

page_text: Another part of this invention relates to improvements in the production of
cements described in the specification of former Letters Patent granted to J. J Sachs
and dated July 8 1881 A D. N° 3012.
According to this part of our said invention we utilize slate dust and preferably
that separated from the slate during the process hereinbefore described for manu-
facturing artificial stone. The said dust is first dried and heated, it is then mixed
with a small quantity of sulphur; melted resin or asphalte is now added until the
mass has about the consistency of oil. The compound is then poured into moulds
and allowed to cool.
To render the cement plastic a small proportion of Russian or other suitable fat
is added
If asphalte has been used instead of resin, coal tar is substituted for Russian fat.
This cement which may be made hard or plastic as desired may be used for
coating electric cables, caulking ships decks, rendering materials water proof and
for many other purposes.
1

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Sanger Shepherd and James Leigh Aspinwall in the Great
Seal Patent Office on the 9th November 1883.
EDWARD SANGER SHEPHERD, of Warwick Road, Paddington, in the County of
Middlesex, and JAMES LEIGH ASPINWALL of the New Vronheulog Slate Company
Limited, Nantlle Vale, in the County of Carnarvon, "IMPROVEMENTS IN THE
MANUFACTURE OF ARTIFICIAL STONE AND CEMENT
"
Our invention relates to the utilization of slate in the manufacture of artificial
stone and cement.
In the production of marketable blocks or slabs of slate by cutting or trimming
and other operations, there is usually a large quantity of this material wasted; in
some cases only about ten per cent, of the slate brought from the quarries being
made use of.
Our invention is chiefly designed to utilize this waste material as hereinafter set
forth.
Artificial stone has heretofore been manufactured by combining various materials,
such as coarse sand or comminuted granite, with Portland or other cement. It is
requisite in this manufacture to employ an "aggregate" sufficiently rough and
porous to form a thoroughly coherent mass when mixed with the said cement, that
is to say, the sand or other material must be sufficiently rough for the cement to
properly adhere thereto, and sufficiently porous to absorb the said cement.
We have discovered that slate fulfils these conditions and we use this material in
the manufacture of artificial stone, instead of the sand, granite or similar material
hitherto used.
In carrying this part of our said invention into practice, we first reduce the slate
to small pieces, preferably of dimensions not exceeding one eighth or one quarter of
an inch in either direction. We then remove the slate-dust and mix the said pieces
with Portland or other cement, and with a hardening solution, such as a dilute
solution of silicate of soda, potash or alumina, or of aluminate of potash, or of
carbonate or chloride of magnesia. A suitable quantity of this hardening solution
is used to render the mass, while moist, sufficiently plastic to enable it to be pressed
into moulds, the quantity varying according to the dryness of the slate.
The
hardening effect of this solution is very perceptible after the mass has set.
Heretofore it has been usual to mix the sand or other material and the cement
with water, and then to place it in moulds and, after it has been allowed to set, to
immerse the moulded blocks in the hardening solution. But according to our
invention we add the hardening solution to the other ingredients before the mass
is moulded so that the said solution will act upon the whole of the mass, instead of
acting only upon the surface of the moulded block as was formerly the case.
The
mass is then tamped or pressed into moulds and allowed to set. The stone is ready
for use after exposure to the weather for three months.
The slate and cement are preferably mixed in about the following proportions,
viz-3 parts by weight of slate to 1 part by weight of cement, but these propor-
tions may be considerably varied according to the quality of stone desired.
We prefer to introduce the hardening solution during the mixing of the slate and
cement. Emery is sometimes added to these materials if it is desired to make
grindstones or polishing wheels thereof.
Another part of our invention relates to the production of an improved cement
of the class described in the specification of former Letters Patent granted to
J. J. Sachs, and dated 8th July A.D. 1881, Nº 3012.
According to this part of our invention we proceed as follows, that is to say :-We
take slate-dust, (for example that separated from the pieces of slate during the

page_text: .
manufacture of artificial stone as herein before described), this slate-dust is first
dried and heated; it is then mixed with sufficient melted resin or common pitch or
asphalte to form a mass having a consistency approximate to that of oil. The
compound thus obtained is poured into moulds and allowed to cool. In some cases
we add to the said mixture a small quantity of sulphur, and we sometimes add
thereto a small proportion of Russian tallow or other suitable fat, or of coal-tar.
If the cement is to be very hard we mix the following ingredients in about the
proportions named, that is to say :-
140 parts by weight of dry slate-dust
80 parts by weight of resin, and
1 part by weight of sulphur
We sometimes dispense with the sulphur; for example, when the cement is to
be used as a substitute for bottling wax, as the sulphur in this case would be liable
to act injuriously upon the contents of the bottles. If it is desired to render the
said cement plastic, we add thereto Russian tallow or other suitable fat in about
the proportions of 1 part by weight of fat to 12 parts by weight of the above
named ingredients, the sulphur being omitted if desired.
We also make hard cement, for paving and similar purposes, by mixing the
following ingredients in about the proportions named, that is to say :-
100 parts by weight of dry slate-dust
100 parts by weight of common pitch or asphalt, and
2 parts by weight of sulphur
:;
To render this cement plastic we sometimes add thereto coal-tar in about the
proportions of 1 part by weight of coal-tar to 12 parts of the other ingredients,
and, in some cases, we, for the same purpose, omit the sulphur from the said cement.
A larger proportion of coal-tar may be added if desired, and less pitch or asphalt
will then be required.
"
Our improved cement may be used for coating electric cables, for caulking ships'
decks, for lining tanks to render the same waterproof and for many other purposes,
some of which are mentioned in the said former specification.
The proportions of the ingredients forming our improved cement may be consider-
ably varied according to the purpose for which it is required.
Having thus fully described the nature of our said invention, and in what manner
the same may be conveniently and advantageously carried into practice, we wish it
understood that we Claim :-
First. The improved artificial stone manufactured of slate, Portland or other
cement; and a suitable hardening solution (with or without the emery), substan-
tially as, and for the purposes, set forth.
Second. The improved cement consisting of slate-dust and resin or pitch or
asphalt (with or without the sulphur or the fat or the coal-tar), substantially as,
and for the purposes, set forth.
In witness whereof we the said Edward Sanger Shepherd and James Leigh
Aspinwall have hereunto set our hands and seals this Ninth day of November in
the year of our Lord One thousand eight hundred and eighty three.