Improvements in the Production of Marble-like Stucco or Plaster- work suitable for Walls, Ceilings, and the like, and in Cement Mixtures therefor.
Year: 1895

page_text: Date of Application, 30th Dec., 1895
Complete Specification Left, 30:h Sept., 1896-Accepted, 12th Dec., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Production of Marble-like Stucco or Plaster-
work suitable for Walls, Ceilings, and the like, and in Cement
Mixtures therefor.
I, MAX HOEFT, of 75 Krausenstrasse, Berlin, Germany, Manufacturer, do
hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the production of stucco or plaster-
work resembling marble and suitable for walls, ceilings and the like. According
thereto a glossy and very durable stucco or plasterwork resembling marble, is
produced by applying to a suitable plaster foundation or ground by means of a
trowel, a mortar or cement (hereinafter called cement) that has been previously
well mixed with pure albumen or pure casein, or with a mixture of pure albumen
and pure casein. After this cement has set, the water exudation from the surface
thereof is repeatedly lightly rubbed off or lightly wiped off with a cloth. When
this has been done, the cement will be found to have a very glossy surface without
any further trouble, that is to say, there is no longer any necessity for ironing the
cement with hot irons, or for grinding or polishing the surface of the cement, or
for rubbing the same with polish or with wax composition, as has heretofore been
usual.
For carrying out my invention I proceed as follows:-
"
<<
I dissolve pure albumen (that is to say, for instance albumen of eggs, or the
albumen to be obtained in commerce) in water, or in a dilute solution of potash or
soda, and to this solution I add slaked lime in powder, or what is still better, in
the form of a lime paste or thick milk. I then work or stir the mass thoroughly,
and add to it a "lean or poor” substance, such as powdered gypsum, marble
dust, limestone dust, powdered quartz i.e., sand, or the like, or a mixture of such
substances. I then work or stir the mass again thoroughly so as to cause all the
substances contained in the said mass to become thoroughly mixed and inter-
mingled. To the cement thus obtained, I may also add other substances, for
example alum for increasing the hardness of the cement; or boric acid, for delaying
the setting of the cement; or colouring agents for colouring the cement.
When the cement is thoroughly and uniformly worked or intermingled, it is
ready for application to the plaster ground or backing for producing the desired.
stucco or plaster work. The plaster ground or backing may be composed of
ordinary grey or lime-mortar plaster, or of gypsum plaster, or of natural or
artificial limestone or sandstone, or of any other, preferably porous but sufficiently
durable material to form a suitable foundation. This ground or backing if it is
not sufficiently fresh or moist to receive the above mentioned cement, is moistened
by spraying it with water, or with other suitable liquid, such for instance as gluc
water, or dilute solution of potash, 1 apply the cement to the ground or backing by
means of a trowel, and distribute it thereby in as uniform a manner as practicable
and endeavour at the same time to render it as dense or close as possible by pressing
the trowel upon it with a suitable degree of pressure. This.object is best effected
by applying the cement in the manner described in the form of a number of super-
imposed thin layers, similarly to the manner of smearing or spreading an ointment
upon a textile fabric. When the cement has been applied to the requisite thickness

page_text: and has been smoothed by spreading and stroking it with the trowel, I then
generally prefer for fine work, to further render the surface of the cement very
close and smooth by the use of a thin solution of pure albumen and slaked lime.
This solution, which should have the consistency of say a water colour or of a glue
colour, is sprayed upon or applied in any other suitable manner to the cement by
means of a brush or other suitable means, and when this solution has become
absorbed by the cement, which takes place quickly, I smooth the surface of the
cement by going over it with the trowel. I repeat this operation until the cement
is quite close and has a perfectly smooth and almost glossy surface. When this
condition has been acquired, then-if the cement is to ornamental by painting-the
painting of the surface of the cement can be commenced. For this purpose I prefer
to use so called "body colours," but other suitable colours may be employed if
desired, such for instance as aniline colours. When the colours have sunk into the
cement and have become dry superficially, I impress them into the still plastic
cement by again going over the surface of the latter with the trowel in a suitable
manner with increased pressure. This operation of impressing the colours must be
done with extreme care so as not to smudge or blur the colours. When the
impressing of the colours is finished, the surface of the cement is left aloue until a
copious watery exudation or sweating is observed on the surface. This moisture
is wiped off with a cloth or removed in any other suitable manner, the wiping
being repeated several times and as soon as the moisture shows itself on the surface
of the cement.
In wiping, and also in smoothing the surface of the cement with the trowel,
I prefer to use powdered talc, which I rub upon the cement, and thereby produce
increased smoothness and cleanness of the cement I also find that the spreading or
smoothing with the trowel is very considerably facilitated thereby.
When the surface of the cement has become dry, the stucco or plastic-work is
finished. It acquires considerable hardness, which increases with the lapse of time,
also a high gloss and a fine marble-like appearance.
If the above mentioned wiping of the watery exudation is omitted, the exudation
dries up into an unsightly greyish white floury powder which disfigures the surface
of the cement. I have found however, that a very fine dull gloss can be imparted
to the cement, by rubbing off the dried-on exudation, and then washing the surface
of the cement with clean water or with soapy water, and then rubbing it dry.
Instead of pure albumen, pure casein can also be used which is dissolved in an
alkaline solution such as solution of caustic potash; or a mixture of albumen and
casein can be employed. But all impure albuminous substances such as blood &c.
are unsuitable for my process because a fine durable gloss cannot be obtained when
they are used, and the cement when mixed with such impure albuminous substances
acquires, even after setting, an unpleasant appearance and becomes injurious to
bealth in consequence of putrefaction of such substances setting in.
In order to entirely prevent such putrefaction when pure albuminous substances
are employed, it is necessary to employ them in the cement only in such small
doses that all the albumen is converted into albuminate of lime which is insoluble
in water.
Instead of mixing the requisite materials for preparing the cement, some time
previous to the commencement of producing the stucco or plaster work, I may
obviously also proceed by mixing the said materials in the dry state, and stirring up
the powder thus prepared, with the requisite water or dilute alkaline solution, just
before commencing to produce the desired stucco or plaster work.
66
I will now give by way of example, a few data as to the best composition of the
kinds of cement that I have in the preparation of my improved stucco or plaster-
work. The cement must always contain pure albuminous substance and lime,
and a substance acting as a poor" or "lean" material. As the "lean" material
I employ, as herein before stated, powdered gypsum, or marble dust, or limestone
dust, or quartz powder, i.e. sand, or a mixture of these materials. When I employ
gypsum as the lean material, the quantities of lime and gypsum should be present

page_text: in the cement approximately in the proportion of 2 to 1, that is to say, 2 kilos. of
lime to 1 kilo. of gypsum. Slight departures from this proportion, up to 20%.
are not of much importance, but are not advisable when it is desired that the
resulting stucco or plaster work shall be permanently free from cracks. With the
mixture of these amounts of lime and gypsum, the weight of which is 3 kilos. in
the example just given, 12 grammes of pure albumen are employed for producing
a smooth cement coating of medium gl ssiness. Half this amount, that is to say,
6 grammes of albumen to 3 kilos. of cement mixture, scarcely allows of successfully
carrying out my process. 20 grammes of pure albumen to 3 kilos. of cement
mixture may be considered to constitute a maximum quantity for a good cement
coating having very great smoothness.
If larger amounts of albumen are used, the cement is certainly rendered more
jelly-like, and can thus be spread smoothly with greater ease, but there is then
liability of putrefaction of that portion of the contained albumen which has not
been converted into albuminate of lime, whereby the cement is rendered injurious
to health.
Alum may be employed in various proportions up to 150 grammes with the
aforesaid mixtures of 3 kilos. of lime and gypsum but even amounts exceeding
100 grammes may give rise to the fear that the alum will subsequently crystallize
and thus tend to damage the surface of the stucco or plaster work. 80 grammes of
alum to 3 kilos. of cement mixture may be considered a suitable proportion for a
good cement of high gloss. Boric acid may be employed in various proportions up
to 50 grammes and even more to 3 kilos. of cement mixture. For medium cement,
generally not more than 15 grammes of boric acid should be employed with 3 kilos.
of cement mixture.
If in place of gypsum, another lean material be employed, such for example as
marble dust, then with 1 kilog. of lime, 2 kilos. of marble dust are to be employed
but here also the proportion may vary within wide limits, if no too great importance
be placed upon the durability of the cement.
Besides marble dust, one or more other lean materials such as powdered
limestone, or quartz powder, may be employed, as herein before mentioned.
In all these cases, where no gypsum, or at least only very small quantities of
gypsum, is or are employed in the cement mixture, the use of boric acid is super-
fluous, because there is no fear of the cement setting too quickly. Also in such
cases, alum
can be employed in smaller quantities than those hereinbefore mentioned,
but it is not advisable to omit it altogether.
Dated this 30th day of December 1905
COMPLETE SPECIFICATION.
Improvements in the Production of Marble-like Stucco or Plaster-
work suitable for Walls, Ceilings, and the like, and in Cement
Mixtures therefor.
I, MAX HOEFT, of 7 Krausenstrasse, Berlin, Germany, 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 :-
This invention relates to improvements in the production of stucco or plaster-
work resembling marble and suitable for walls, ceilings and the like. According
hereto a glossy and very durable stucco or plasterwork resembling marble, is

page_text: produced by applying to a suitable plaster foundation or ground by means of a
trowel, a mortar or cement (hereinafter called cement) that has been previously
well mixed with pure albumen or pure casein, or with a mixture of pure albumen
and pure casein. After this cement has set, the watery exudation from the surface
thereof is repeatedly lightly rubbed off or lightly wiped off with a cloth. When
this has been done, the cement will be found to have a very glossy surface without
any further trouble; that is to say, there is no longer any necessity for ironing the
cement with hot irons, or for grinding or polishing the surface of the cement,
or for rubbing the same with polish or with wax composition, as has heretofore
been usual.
For carrying out my invention I proceed as follows:-
"
I dissolve pure albumen (that is to say, the albumen obtainable in commerce
and called albumen of eggs or of serum) in water, or in a dilute solution of potash
or soda, and to this solution I add slaked lime (burnt lime slaked while hot) in
powder, or what is still better, in the form of a lime paste or thick milk. I then
work or stir the mass thoroughly, and add to it a
"lean or ❝ poor" substance,
such as powdered gypsum, (i.e. unburnt or over-burnt gypsum, not plaster of
Paris), finely powdered marble, or lime-stone, powdered quartz, i.e. sand or the like, or a
mixture of such substances. The quantity of water or dilute alkaline solution used
is such as to form with the added materials, a plastic mass of the consistency
ordinarily used for plaster. I then work or stir the mass again thoroughly so as
to cause all the substances contained in the said mass to become thoroughly mixed
aud intermingled. To the cement I may also add other substances, for increasing
the hardness of the cement; or boric acid for delaying the setting of the cement;
or colouring agents for colouring the cement, as well understood. When the
cement is thoroughly and uniformly worked or intermingled, it is ready for
application to a plaster ground or backing for producing the desired stucco or
plaster work. The plaster ground or backing may be composed of ordinary grey
or lime-mortar plaster, or of plaster of Paris, or of natural or artificial limestone
or sandstone, or of any other preferably porous but sufficiently durable material to
form a suitable foundation. This ground or backing, if it is not sufficiently fresh
or moist to receive the above mentioned cement, is moistened by spraying it with
water, or with other suitable liquid, such for instance as glue water, or dilute
solution of potash. I apply the cement to the ground or backing by means of a
trowel, and distribute it thereby in as uniform a manner as practicable, endeavouring
at the same time to render it as dense or close as possible by pressing the trowel
upon it with a ruitable degree of pressure. This object is best effected by applying
the cement in the manner described in the form of a number of superposed thin
layers, successively applied and each smoothed over similarly to the manner of
smearing or spreading an ointment upon a textile fabric. When the cement has
been applied to the requisite thickness and has been smoothed by spreading and
stroking it with the trowel, I then generally prefer for fine work, to further render
the surface of the cement very close and smooth by the use of a thin solution of
pure albumen and slaked lime prepared by mixing some of the cement prepared as
herein before described with water or with a dilute solution of potash. The
solution, which should have the consistency of say a water colour or of a glue
colour, usually the former, is sprayed upon or applied in any suitable manner to
the cement by means of a brush or other suitable means, and when it has become
absorbed by the cement which takes place quickly, I smooth the surface of the
cement by going over it with the trowel. I repeat this operation until the cement
is quite close and has a perfectly smooth and almost glossy surface. When this
condition has been acquired, then-if the cement is to be ornamented by painting-
the painting of the surface of the cement can be commenced. For this purpose
I prefer to use so called "body colours," but other suitable colours may be employed
if desired, such for instance as aniline colours.
When the colours have sunk into the cement and have become dry superficially,
Fimpress them into the still plastic cement by again going over the surface of the

page_text: latter with the trowel in a suitable manner with increased pressure. This operation
of impressing the colours must be done with extreme care so as not to smudge or
blur them.
When the impressing of the colours is finished, the surface of the cement is left
alone until a copious watery exudation or sweating is observed on the surface..
This moisture is then wiped off with a cloth, or removed in any other suitable
manner, the wiping being repeated several times and as soon as the moisture shows. -
itself on the surface of the cement.
In wiping, and also in smoothing the surface of the cement with the trowel,.
1 prefer to use powdered tale, which I rub upon the cement and thereby produce
an increased smoothness and clearness of the cement. I also find that the spreading
or smoothing with the trowel is very considerably facilitated thereby.
When the surface of the cement has become dry the stucco or plaster work is
finished. It requires considerable hardness which increases with the lapse of
time also a high gloss, and a fine marble-like appearance.
If the above mentioned removal of the watery exudation be omitted, the
exudation dries up into an unsightly greyish white floury powder which disfigures.
the surface of the cement. I have found however, that a very fine dull gloss can
be imparted to the cement, by rubbing off the dried-on exndation, and then.
washing the surface of the cement with clean water or with soapy water, and then
rubbing it dry.
Instead of using pure albumen as hereinbefore described, pure casein can also
be used which is dissolved in alkaline solution such as solution of caustic potash ;.
or a mixture of albumen and casein can be employed. But all impure albuminous
substances such as blood &c. are unsuitable for my process, because a fine durable
gloss cannot be obtained by their use, and the cement when mixed with such
impure albuminous substances acquires, even after setting, an unpleasant
appearance and becomes injurious to health in consequence of putrefaction of
such substances setting in.
In order to entirely prevent such putrefaction when pure albuminous substances.
are employed, it is necessary to employ them in the cement only in such small
doses that all the albumen is converted into albuminate of lime which is insoluble
in water.
Instead of mixing the requisite materials for preparing the moist cement, some-
time previous to the commencement of producing the required stucco or plaster
work, I may obviously also proceed by mixing or grinding the said materials in the
dry state, and stirring up the powder thus prepared with the requisite quantity of
water or dilute alkaline solution before commencing to produce the desired stucco.
or plaster work.
68
I will now give by way of example, a few data as to the best composition of the
kinds of cement that I have used in the preparation of my improved stucco or
plaster work. The cement must always contain a pure albuminous substance and
lime, and a substance acting as a poor' or "lean" material. As the "lean"
material I employ, as hereinbefore stated, finely powdered gypsum (unburnt or
overburut), or finely powdered marble or limestone, or quartz powder i.e. sand, or
a mixture of these materials. When I employ gypsum as the lean material, the
quantities of lime and gypsum should be present in the cement approximately in
the proportion of 1 to 2 that is to say, 1 kilo. of lime to 2 kilos. of gypsum. With
the mixture of these amounts of lime and gypsum, the weight of which is 3 kilos.
in the example just given, 12 grammes of pure albumen are employed for producing
a smooth cement coating of medium glossiness. 3 to 4 grammes of albumen
to 3 kilos. of cement mixture, scarcely allows of successfully carrying out my
process. 20 grammes of pure albumen to 3 kilos. of cement mixture may be
considered to constitute a maximum quantity for a good cement coating having
very great smoothness.
If larger amounts of albumen are used, the cement is rendered more jelly-like,
and can thus be spread smoothly with greater ease, but there is then liability of

page_text: putrefaction of that portion of the contained albumen which has not been
converted into albuminate of lime whereby the cement is rendered injurious to
health.
Alum may be employed in various proportions up to 150 grammes with the
aforesaid mixture of 3 kilos. of lime and gypsum but even amounts exceeding
100 grammes may give rise to the fear that the alum will subsequently crystallize
and thus tend to damage the surface of the stucco or plaster work: 80 grammes
of alum to 3 kilos. of cement mixture may be considered a suitable proportion for
a good cement of high gloss.
If in place of the gypsum, another lean material be employed, such for example
as powdered marble, then with 1 kilog. of lime, 2 kilos. of finely powdered marble
are to be employed, but here also the proportion may vary within wide limits, if no
too great importance be placed upon the durability of the cement.
Besides powdered marble, one or more other lean materials such as powdered
limestone, or quartz powder, may be employed, as hereinbefore mentioned.
In all these cases, where no gypsum, or at least only very small quantities of
gypsum, is or are employed in the cement mixture, the use of boric acid is
Buperfluous, because there is no liability of the cement setting too quickly. Also
in such cases, alum can be employed in smaller quantities than those hereinbefore
mentioned, but it seems not to be advisable to omit it altogether.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. For the production of stucco or plaster-work, a cement powder consisting of
an intimate mixture of pure albumen of the kind herein referred to, burnt lime
and a "lean" 66
or poor" substance such for example, as natural or unburnt gypsum,
overburnt gypsum, marble, limestone or sand, or a mixture of two or more of these
substances, as set forth.
"
2. For the production of stucco or plaster-work, cement consisting of a plastic
mixture of pure albumen of the kind herein referred to in aqueous or alkaline
solution, burnt lime, and a "lean $
or poor "substance such as for example, finely
divided natural or unburnt gypsum, over-burnt gypsum, marble, limestone and
sand, or a mixture of two or more of such substances, as set forth.
3. The herein described cement mixtures consisting of albumen of the kind
herein referred to, burnt lime and a lean or poor substance substantially in or about
the proportions specified for the purpose set forth.
4. The production of stucco or plaster work with a glossy surface by smoothly
spreading a cement of the kind specified in the preceding claims in thin layers and
by the aid of a trowel upon a plaster ground or backing, coating the surface of the
cement so applied with a thin solution of the cement and effecting a perfect closing
or condensation of the said surface by stroking it with a trowel, thereby imparting
a high polish to such surface, substantially as herein described.
Dated this 30th day of September 1896.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.