The Manufacture of an Improved Compound for Coating and Decorating Walls and other Surfaces, and for the Production of Casts or Mouldings, and for analogous purposes.
Year: 1895

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c. Act, 1883), as required by
the decision of the Comptroller General of the 5th day of February 1896.
Date of Application, 8th July, 1895-Accepted, 17th July, 1895
COME DELE DI MOLTIVATION (AMENDED).
The Manufacture of an Improved Compound for Coating and
Decorating Walls and other Surfaces, and for the Production of
Casts or Mouldings, and for analogous purposes.
1, MELVIN BATCHLOR CHURCH, of Grand Rapids, State of Michigan, U.S.A.,
Manufacturer, 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 relates to the manufacture of an improved adhesive compound for
coating walls and other surfaces and for the production of casts or mouldings, and
for relief decoration, modelling and the like.
The object of my said invention is to produce an adhesive compound somewhat
similar to that described in the Specification of my former English Letters Patent,
dated April 4th 1882, No. 1620, and known as "Alabastine," composed of animal
glue and calcined gypsum and sulphate of zinc in dry powdered form, but which
when mixed with cold water will make a practical adhesive coating for walls etc.,
while my alabastine made as described in said Patent No. 1620 required to be
mixed in hot water for such use.
The Specifications of a Patent issued to me in the United States of America,
April 6th 1875, No. 161,591 describes the compound of calcined gypsum and
glue, without sulphate of zinc, as applied with brushes and in plastic form, and
describes the retarding effect of glue on calcined gypsum.
In carrying out my invention I mix together in suitable proportions strongly
adhesive animal glue and a suitable base, such as calcined gypsum, and subject the
mixture to heat supplying moisture if necessary (using care to not overheat the
glue as will herein be more particularly described); by this treatment the glue
is brought to a condition to be readily ground extremely fine in company with
the base, and with which it is thus intimately mixed; a compound is thus formed
which can be readily reduced by thorough grinding in any mill suitable for fine
grinding without overheating by friction, to such a degree of fineness as to enable
the same to be advantageously prepared for use for the purposes specified by
adding cold water, or water at ordinary atmospheric temperatures.
I prefer to use calcined gypsum as the base, to make a compound adapted for
slow setting casts and for modelling in relief, and this also forms a durable adhesive
coating when reduced with sufficient amount of cold water to lay on with brushes, and
subsequent coats can be applied from time to time for many years without removing
the old coats, which harden with age, and the coating will not rub off or scale from
hard surfaces.

page_text: I describe this invention as adapted for using calcined gypsum as it requires
more care to properly use said base.
In carrying out my invention I mix and heat the materials in such quantities
that the mass
can be readily and thoroughly stirred and the moisture readily
evaporated.
It is important that the glue should be reduced to an extremely fine divided
condition to render the coating sufficiently adhesive when cold water is added for
reducing the dry compound to a condition to be spread with brushes, and to render
the glue effective as a retarding element when the base employed is calcined
gypsum. This retarding action is the preventing of the calcined gypsum from
re-taking its water of crystallization, for a sufficient time for practical use without
injuring its setting power, which setting or hardening usually begins to take place
in one to five hours, according to amount of water used for mixing; the setting
taking place quickest with least amount of water.
Prior to this invention it was necessary to use hot water for preparing such dry
compositions for use for adhesive coatings, as, the glue not being reduced to a
sufficient fineness (being ground separately and then mixed with the base), required
very hot water to divide and distribute it, and to make it available as an adhesive
agent as well as to control the setting when calcined gypsum was used, and
mistakes often occurred by using water not sufficiently hot for the purpose. By
this invention 1 avoid all such inconveniences, and much imperfect work, as well
as saving time and trouble in preparing the material for use.
It is advantageous to use a small proportion of salphate of zinc, or an equivalent
substance, with the glue and the gypsum or other base when it is desired to
neutralize to some extent the retarding effect of the glue upon the gypsum, and it
also helps to prevent the decomposition of animal glue.
In making my "alabastine" compound according to my present invention
I proceed as follows, that is to say I prefer to first calcine the gypsum and to
place it in a suitable receptacle, pan or kettle and apply heat thereto, the gypsum
being agitated by suitable means while the heating is continued, and I pour into
the gypsum, gradually, while it is being heated and agitated, the animal glue in
liquid form, maintaining sufficient heat to quickly drive off the moisture; after the
desired amount of glue is thus introduced I use care to see that the heat is reduced
or removed from the receptacle or the contents removed from it, as soon as the
moisture from the glue is driven off (that is the free moisture); this precaution is
necessary to avoid overheating the glue or heating it beyond the point required to
thoroughly dry it.
It is important that the moisture from the glue should be driven off as soon as
practicable from the calcined gypsum or other base, as the adhesive qualities of
the glue will be impaired if left too long in a wet condition mixed with the base
and when calcined gypsum is used it would partially or wholly absorb the water
from the liquid glue if left too long, and the glue would also be injured by being
absorbed by the gypsum.
Where uncalcined gypsum, or that partially calcined, is used, the glue should not
be added until the gypsum has been calcined, as otherwise the adhesive nature of the
glue will be injured or destroyed by the high degree of heat required to thoroughly
calcine the gypsum.
I have also accomplished the desired results by mixing the animal glue in dry
powdered form, with the gypsum or other base, by adding moisture to the mass
while it is being heated and agitated as above described; this can be done by
slowly stirring in water while the mass is being agitated, or by using a base which
contains sufficient moisture to soften the glue, thus rendering the glue in a condition
to be more readily ground to a sufficient fineness than if the base and the glue, as
ordinarily dried and ground, were simply mixed and ground together.
When the sulphate of zinc is used I either introduce it directly into the vessel
during the drying process described or add it to the compound at any time.
The proportions of the several ingredients I find it advantageous to use are as

page_text: follows, viz. To every hundred weight of the calcined gypsum I add from 5 to
8 lbs. of good animal glue (as in dry form) and from half to one pound of sulphate
of zinc, or its equivalent, when such substance is used. I use about one pound of
water to each lb. of dry glue.
The proportions will however be varied to some extent according to the purpose
for which the compound is required, and according to the strength or quality of
the glue employed, but a sufficient quantity of animal glue must be used in the
manufacture of my improved compound, to impart to the said compound the
requisite degree of adhesiveness for the purposes herein specified, and without
injuring the setting properties where a calcined gypsum base is used, when it is
desired to make a setting compound.
In order to ensure the most efficient working of the compound in respect of both
the adhesion and the setting thereof use the better qualities of animal glue, as
the cheaper qualities of glue such as are generally employed for merely retarding the
setting of calcined gypsum, even when used in or about in the proportions above
stated, will not impart the desired degree of adhesiveness for the compound, and
will retard the setting of the gypsum too much, or so much as to injure its setting
properties, that is, its power to re-crystallize, as it will do in time after it is applied,
when it obtains sufficient moisture from the air, and as the glue loses its strength;
the adhesion becomes more perfect with age, thus forming permanent coatings and
relief decoration.
I have found that the heating and drying can be advantageously and quickly
done with direct fire under the receptacle by using gas or oil burners, so as to
admit of regulating the heat and to shut it off wholly when the moisture has been
driven out as above explained; it can also be done in what is well known to
engineers as a jacket pan or receptacle, that is, having a space between the fire and
the material to contain water or steam to avoid burning while cooking or drying,
and such drying may be facilitated by adding vacuum appliance as known to
engineers, but I have found the method with direct heat above described practical
and expeditious.
The method I describe in my Specification with English Patents, June 13th 1882
(grinding mills) is well adapted for grinding the compound, either before or after
glue is added.
Suitable colors may if desired be added to the compound as it comes from the
kettle to produce tints, the said colors being perfectly ground in, or the coloring
matter may, in some instances, be put into the mixing and drying receptacle and
mixed with the compound therein, that is, such colors as will not be injured by the
heating or re-grinding.
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 improved process above described, consisting essentially of animal
glue and calcined gypsum or a similar base (and moisture) in or about in the
proportions above stated (with or without a small proportion of sulphate of zinc)
and applying heat, for the purpose of rendering the glue in a condition to be
readily ground sufficiently fine so that the resulting compound will work efficiently
and make an adhesive coating when mixed with cold water, and applied, as
described above.
Second. The improved process above described, consisting in heating calcined
gypsum, or a similar base, in a receptacle or pan, slowly pouring into the same
while in a heated, in or about in the above named proportions, animal glue, which
has been dissolved in water, and evaporating the water, and reducing the compound
to a very fine condition so that the resulting compound will work efficiently and
make an adhesive coating when mixed with cold water (with or without a small
percentage of sulphate of zinc) for the purpose specified herein.
Third. A dry compound such as above described, consisting essentially of

page_text: animal glue and a base, such as calcined gypsum or a similar base, in or about
in the above named proportions, in such a fine state of division that the said
compound will work efficiently and make an adhesive coating when mixed with cold
water, with or without a small percentage of sulphate of zinc.
MELVIN BATCHLOR CHURCH.