An Improved Process for Hardening, Preserving, and Preparing Oolitic and other Limestones.
Year: 1888

page_text: Date of Application, 19th Oct., 1888
Complete Specification Left, 17th July, 1889-Accepted, 19th Oct., 1889
PROVISIONAL SPECIFICATION.
An Improved Process for Hardening, Preserving, and Preparing
Oolitic and other Limestones.
I GEORGE JAMES RANDALL of Marbrier, Longley Road, Tooting Graveney, in the
County of Surrey, Stone and Marble Mason, do hereby declare the naturo of this
invention to be as follows:-
:―
This invention relates to an improved process for hardening, preserving and
preparing oolitic and other limestones, whereby a hardened face is produced upon
the softest limestones and particularly upon oolitic limestones, rendering them
impervious to atmospheric influences and enabling them to take and retain every
kind of enamel. The process is a very economical one, and limestones treated
according to this process possess all the durability, and are much more economical
than slate or marble.
According to this invention, the limestone to be treated, is first heated sufficiently
to destroy all vegetable germs to drive off all quarry damp, and to render it more
absorbent. It is then immersed for any suitable time in a solution of milk of lime,
acetic acid, and cane sugar or molasses, and when taken out is rubbed to a face
with fine grit and allowed to dry in the atmosphere, after which it is subjected
to a moderate dry heat, and allowed to cool slowly.
If intended for enamelling, the face is preferably rubbed whilst the stone is hot
with cotton waste saturated with vegetable or mineral oil.
Dated this 10th day of October 1800
"
CASTLE SMITH,
Per F. W. Golby,
Invention" Office, 54, Fleet Street, London, E.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Process for Hardening, Preserving, and Preparing
Oolitic and other Limestones.
I, GEORGE JAMES RANDALL, of Marbrier, Longley Road, Tooting Graveney, in the
County of Surrey, Stone and Marble Mason, 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 :-
This invention relates to an improved process for hardening, preserving and
preparing oolitic and other limestones whereby a hardened face is produced upon
the softest limestones and particularly upon oolitic limestones rendering them
impervious to atmospheric influences, and enabling them to take and retain enamel.
The process is a very economical one and limestones treated according to this
process possess all the durability of and are much more economical than slate or
marble.
According to this invention, I prepare a compound of milk of lime, acetic acid and
cane sugar in about the following proportions.
Milk of Lime 1 Gallon.
Ordinary Cane Sugar 1lb.
Acetic acid one twentieth part of the volume of the milk of lime and cane sugar.
The milk of lime, which I prefer to use when treating ordinary limestones, I make
by adding one pound and a half of lime to a gallon of water, I add rather more
water when treating fine stones. The lime is placed in a vat or pan and the water
added, when brought into a state of fusion I add the cane sugar and stir until the
ingredients have become perfectly fused and thoroughly incorporated with each other.

page_text: I then add the acetic acid and allow the whole to settle. Molasses may be substituted
for the cane sugar in the compound, when the proportions are about as follows:-
Milk of Lime 1 Gallon.
Molasses according to its consistency.
Acetic acid one twentieth part of the volume of the milk of lime and molasses.
The limestone to be treated is first. subjected to a temperature sufficient to destroy
all vegetable germs, to drive off all quarry damp and to render the stone more
absorbent.
After having removed all loose particles from the surface, the stone is immersed in
a bath of the compound of milk of lime, acetic acid, and cane sugar or molasses for
à time varying according to the size and density of the stone and the depth of
saturation required. Or the compound may be put on with a brush, if only a thin
coat or face is required. The stone is then taken out and after being rubbed to a face
with fine grit is allowed to dry in the atmosphere, after which it is subjected to a
diffused (not a direct) dry heat of from 130 to 160 F., such as the diffused dry heat
of a hot air oven. The stone is now ready for ordinary use, but for enamelling I
prefer to rub the face while the stone is hot with cotton waste moistened with linseed
or mineral oil, preferably kerosene, or I rub the face of the stone with cotton waste
moistened with any other vegetable oils.
The action in this process is as follows:-The acetic acid in the compound remains
in solution inactive until brought into contact with carbonate of lime, or limestones
when it instantly decomposes the face, generating carbonic acid gas, and by the time
the acetic acid has spent itself, sufficient of the carbonic acid so evolved has been
absorbed by the compound (any excess having been driven off). To perfect. the
process the requisite heat must be applied thus providing the stone with a face which
is proof against ordinary atmospheric influences and is impervious to moisture.
When the stone to be treated is fixed in position as on a building, then the
compound may be applied with a brush either with or without the application of
heat.
The action throughout is a chemical one, that part of the limestone which has
become impregnated with the compound forms after treatment material of a different
nature which is similar in its character to marble.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
First. The process employed for hardening preserving and preparing oolitic and
other limestones substantially as described.
Second. The use in the manner and for the purposes mentioned of the compound of
milk of lime acetic acid and cane sugar or molasses prepared substantially in the
manner herein before set forth.
Third. The production of a hardened face or of a hardened material from soft
oolitic and other limestones substantially in the manner hereinbefore set forth.
Dated this 17th day of July 1889
CASTLE SMITH,
Per F. W. Golby,
"Invention" Office, 54, Fleet Street, London, E.C., Agent for the Applicant.