New or Improved Manufacture of Material suitable for Wall Plaster and similar purposes.
Year: 1898

page_text: Date of Application, 7th Sept., 1898
Complete Specification Left, 28th Apr., 1899-Accepted, 29th July, 1899
New or Improved Manufacture of Material suitable for Wall Plaster
and similar purposes.
A communication from abroad from FEODOR Boas, of the Town of St. Hyacinthe,
Province of Quebec, Dominion of Canada, Gentleman.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention to be as follows;-
This invention has reference to a new or improved manufacture of a compound
or material suitable for use as wall plaster and for other similar purposes. The
said compound consists primarily of a mixture of crushed serpentine rock and
the fine short fibred asbestos naturally embedded therein, which I call asbestos
serpentine, all of which has been heretofore a waste product in asbestos mining.
With this mixture is incorporated a small percentage of lime. The preferred
proportion of parts is about 1 part of lime to from 6 to 12 parts of the crushed
rock and asbestos, by weight, according to the strength of the lime. The pro-
portions may be materially varied with advantage, however, when the product
is to be employed for different purposes.
In place of lime, Portland cement, clay, or other material which will render
the compound adhesive when mixed with water, may be used. In some cases,
sand may be added to the asbestos, lime and water.
The serpentine rock and fine short fibred asbestos, which together form the
main constituent of the improved .compound, are, as above stated, a waste pro-
duct of asbestos mines and asbestos factories. No use has been known for it
prior to this invention, and it could only be got rid of at great expense. By
reason of this invention, however, it becomes of great value and importance.
It is essential to the production of the best results, that the asbestos or crushed
serpentine rock, should be mixed with the lime while the same is hot in the
slacking."
process of hydration, or, as it is commonly termed "
When this is
done the silica and magnesia of the asbestos and serpentine rock become chemi-
cally combined with the lime and produce a double silicate of lime and magnesia.
Thus the resultant plaster, which is called "asbestic plaster" is not a mere
mechanical mixture or agglomeration of elements but it is a single integral
chemical compound, a substance which cannot be disintegrated except by chemical
action.
The preferred method of carrying out the invention is to add the crushed and
comminuted asbestos and serpentine rock to the lime in the process of hydra-
tion, or immediately thereafter. Thus, a certain amount of water may be added
to the lime to start the process of hydration, and then quantities of the com-
minuted asbestos and serpentine rock are added from time to time with addi-
tional quantities of water as needed. This saves the time and expense
of

page_text: comminuting the lime itself, as it is disintegrated by the water in the process
of hydration.
The advantages of the herein described compound over others heretofore pro-
duced for a similar purpose, are that the short-fibred asbestos gives lightness,
flexibility and strength to the compound, while at the same time its shortness
of fibre permits of the formation of a dense, homogeneous structure which is
fireproof and will not crack or curl under the action of heat and subsequent
application of water. As herein before explained the improved product differs
radically from any compounds of long fibred asbestos with other materials hereto-
fore suggested, in that it is a permanent chemical compound which not only is
not disintegrated by the action of the weather, but is actually hardened by expo-
sure to the atmosphere. Thus plaster made therefrom becomes harder at the
end of two or three years of use than it was when originally placed in position
on the wall. This result is probably due to the absorption of additional oxygen
from the atmosphere, or perhaps it is merely the result of the more complete
carrying out of the chemical combination originally set up in the making of the
plaster. But whatever the reason the above stated result is an observed fact.
The use of the short fibred asbestos permits the chemical action between it and
the lime and water to take place more completely, effectively and quickly, than
in the case where the long fibred asbestos is used.
The result is a fine wall plaster, which can be applied with a trowel in the
usual way. It is fireproof, very strong, hard, susceptible of a fine finish, and
is a non-conductor or bad conductor of sound. By reason of the crushed serpen-
tine rock and asbestos being a waste product, a perfectly fire-proof, non-absorbent,
antiseptic wall finish of this material of the usual thickness, can be supplied at
a lower price than is the case with other plaster, thus bringing it within the
reach of everyone. Furthermore, as the plaster produced by this invention is
much stronger than any plaster heretofore made, it is not necessary to apply
so thick a coating as usual, and additional economy, with a reduction of weight
on the building, results. It is of especial value in hospitals, sanitariums, etc.
Nails can be driven through it without the material splitting or crumbling. It
may be made into sheets, boards or slabs, and used like lumber, by nailing it
to the frame of a building.
Asbestic plaster being a non-conductor or bad conductor of heat, great
economy in fuel results in the heating of rooms whose walls are covered with
such material. On the other hand, in summer the same non-conductivity of the
plaster tends to keep the interior of the apartment cool to the extent of prevent-
ing the heat absorbed from the sun's rays by the roof and walls of the building,
from being conducted to the interior.
Dated this 7th day of September 1808
W LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.
New or improved Manufacture of Material suitable for Wall Plaster
and similar purposes.
A communication from abroad from FEODOR BOas, of the Town of St. Hyacinthe,
Province of Quebec, Dominion of Canada, Gentleman.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare

page_text: --
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 consists of an improved compound of matter to be used as wall
plaster and for other similar purposes.
The said compound results from a mixture of crushed chrysotile serpentine
rock, heretofore a waste product in asbestos mining, and a small proportion of
lime with a sufficient quantity of water. The mineral chrysotile finds applica-
tion in the arts as one of the forms of asbestos when it occurs of sufficient length
of fibre. In mining the commercial chrysotile a large quantity of serpentine
rock is of necessity removed and thrown upon the dump as waste material.
Chrysotile is essentially a hydrated basic silicate of magnesia and it generally
occurs in nature as fibrous layers in massive serpentine which chemical analysis
shows to be of practically the same chemical composition as the fibrous mineral.
The massive serpentine is then the gangue of the fibrous chrysotile. This mas-
sive serpentine gangue often contains small seams of chrysotile but they are too
short fibre to find use as ordinary asbestos.
This waste material accumulates at the mines and around the factories and it
is a trouble and expense to the industry. Many attempts have been made to
utilize this waste, but previous to my invention, without success. This invention
therefore provides a useful outlet for this waste material.
My correspondent has discovered that when this waste serpentine rock con-
taining short fibred chrysotile is crushed and mixed with quick lime in the
proper proportions and then a suitable amount of water added, the silicate of
magnesia and the quick lime react together chemically and a double silicate of
lime and magnesia is formed. This double silicate of lime and magnesia acts
as a cement and binds the mass of the material together, forming a light flexible
and strong structure which possesses particular advantages as a wall plaster and
for similar purposes.
In carrying out this invention it is essential to use only a moderate amount of
quick lime, in order to get the full benefit of the binding. properties of the
double silicate of lime and magnesia as a cement. If a large proportion of lime
is used then much carbonate of lime will be formed during the setting of the
plaster, and this dilutes and, weakens the silicate cement.
This plaster therefore differs from all other similar compounds in utilizing
a double silicate of lime and magnesia as the chief binding material and this
double silicate is formed by the chemical interaction of hydrated basic silicate
of magnesia and ordinary quick lime.
Although the massive serpentine and fibrous chrysotile differ so much in their
physical conditions yet chemically they are practically of the same composition.
The composition of the mass is about as follows; from 30 to 40 per cent. of
magnesia, 35 to 40 per cent. of silica, 9 to 12 per cent. of water, and small amounts
of impurities.
On crushing the rock the short fibred chrysotile is broken up into short fibres
and the massive serpentine becomes granular.
The preferred proportion of parts is one part of lime to from six to ten parts
of the crushed chrysotile serpentine rock, by weight, according to the purity of
the lime, the purer the lime the less the quantity required. The proportions may
be varied beyond these limits, however, in special cases.
In place of lime may be used other material which would chemically combine
to form a double silicate with the crushed chrysotile serpentine rock, in the
presence of water.
A sufficient quantity of water should be used to slake the lime and to reduce
the mixture of materials to a plastic mass.
One method of combining these constituents is to mix the crushed chrysotile
serpentine rock and lime or equivalent materials of the character mentioned,
and then add the necessary amount of water. The advantage of this method is

page_text: that it produces a dry plaster which may be shipped to consumers ignorant of
the necessary proportions of the constituent parts, and this prepared plaster can
be wet up for use by any plasterer who has skill enough to know when his materials
are of the right consistency to make a good job. The essential point, however,
is to ensure the mixing of the crushed chrysotile serpentine rock with the lime
while the same is hot in the process of hydration, or as it is commonly termed
"slaking," and this may be done with less labor and expense where it is to be
immediately applied to the wall by first slaking the line and then adding the
crushed chrysotile serpentine rock in excess to the lime during this process of
hydration, or immediately thereafter. This saves the time, labor and expense
which would be otherwise consumed in crushing and screening the lime to the
degree of fineness necessary to secure a perfectly even, dry mixture of the lime
with the crushed chrysotile serpentine rock.
When the slaking of the lime is thus done in the presence of the crushed
" slaked" lime
chrysotile serpentine rock, or when the latter is added while the
is still hot from the process of hydration, the silica and magnesia of the crushed
chrysotile serpentine rock become chemically combined with the lime, and as a
result a double silicate of lime and magnesia is formed. Thus the resultant
plaster, which I call "asbestic," is not a mere chemical mixture or aggregation
of elements, but it is largely the result of chemical interaction, producing a
stable, chemical compound. The wall plaster thus formed combines lightness
and flexibility with strength and density of structure. It is fireproof to the
highest degree and will not crack or curl under the action of the heat and sub-
sequent application of water. It is also susceptible of a fine surface finish and
is a bad conductor of sound. As it is stronger than any other plaster, it is not
necessary to have as thick a coating applied as usual, and additional economy,
with a reduction of weight on the building, result. The plaster does not dis-
integrate with age and the action of moisture, on the contrary it grows harder
with age and exposure. It is of especial value in hospitals, sanitariums, &c.
Nails can be driven through it without the material splitting or crumbling.
It may be made into sheets, boards, or slabs, and used like lumber, by nailing
it to the frame of a building.
Asbestic plaster being a bad conductor of heat, great economy of fuel results
in the heating of rooms whose walls are covered with asbestic plaster. On the
other hand, in summer the same non-conductivity of the plaster tends to keep
the interior of the apartment cool to the extent of preventing the heat absorbed
from the sun's rays on the roof and walls of the building, from being conducted
to the interior.
It is moreover, far more resistant to the action of acids than ordinary lime
plasters where the building material is carbonate of lime. In fact pieces of this
plaster have been immersed in hydrochloric acid for several days without being
entirely disintegrated; while such treatment applied to ordinary lime plasters
would dissolve out all the cementing carbonate of lime and the plaster would bé
entirely disintegrated.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:
1. A composition of matter comprising silicate of magnesia largely in excess,
mixed with quick lime and water, substantially as described.
2. A composition of matter comprising silicate of magnesia cemented together
by double silicate of lime and magnesia, substantially as described.
3. A composition of matter to form a wall plaster comprising granular and
fibrous silicate of magnesia cemented together by double silicate of lime and
magnesia, substantially as described.
4. A composition of matter in which a double silicate of lime and magnesia
is the chief binding agent.

page_text: 5. A composition of matter to form a dry wall plaster comprising comminuted
silicate of magnesia, largely in excess, mixed with quicklime, substantially as
described.
6. A slab of silicate of magnesia cemented together by double silicate of lime
and magnesia, substantially as described.
7. A composition of matter consisting of crushed chrysotile gangue mixed with
quick lime, substantially as described.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.