Improvements in the Manufacture of Plaster.
Year: 1891

page_text: Date of Application, 10th Nov., 1891
Complete Specification Left, 9th Aug., 1892-Accepted, 10th Sept., 1892
a
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Plaster.
I JOHN CALDWELL BLOOMFIELD, Cement Plaster Manufacturer of Bloom-
field & Co.'s Castle Caldwell Works, Leggs, County Fermanagh, Ireland, do
hereby declare the nature of this invention to be as follows:-
The object of this invention is to manufacture a plaster which is capable of
being enamelled or which dries with an enamelled face.
According to this invention I mix raw shale with hydraulic lime or other cement
in a dry and natural state. The shale is broken coarse when an ordinary plaster
only is required, which may-be-afterwards enamelled if so desired; but when
finely divided or ground the plaster so produced dries with an enamelled face.
Dated this 10th day of November 1891.
F. W. GOLBY,
36, Chancery Lane, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Plaster.
I JOHN CALDWELL BLOOMFIELD, Cement Plaster Manufacturer, of Bloom-
field & Co.'s Works, Castle Caldwell, Leggs, County of Fermanagh, Ireland, 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:-
The object of this invention is to manufacture plaster by using as one of the
ingredients and in its raw and natural state a material which at present is little
better than a waste product namely raw shale.
In manufacturing plaster in accordance with this invention, I mix raw shale
with hydraulic lime or other cement in a dry and natural state. The shale may be
broken coarse, or it may be finely divided or ground according to the finish required.
Plaster so produced will be less expensive than the ordinary plasters and will dry
with a fine smooth face; but when the shale has been ground previous to mixing,
the plaster dries with a glossy polished surface which may be described as an
enamel face.
As a base or first coat of a plaster covering for walls, ceilings etc., I use about
2 or 3 parts of broken shale (not ground) to 1 part of hydraulic lime or other
cement and pass the ingredients through a inch sieve. This compound when
mixed with water may be applied in the ordinary manner. When the coat has set,
a coat of finer materials may be added.
For a finer coat and one which when dry possesses an enamelled or polished face,
I use about 2 or 3 parts of shale, which has been finely divided or ground,
to one part of hydraulic lime or other cement. I use this compound when pre-
paring a fine stuff or top finishing coat for walls, ceilings &c., I mix it with water
and apply it in the ordinary manner, and when it has set it possesses a hardened
polished or enamelled face."
The herein described compound of hydraulic lime and ground or unground shale
may be used for making ornaments, figures, moldings. and the like purposes to
which plaster is applicable.
I am aware that it has been already proposed to make a plaster from Portland
cement and burnt shale, but with my invention, shale in its raw or unburnt state
is utilized and the time involved and expense consequent upon the calcining of the
Price 8d.1

page_text: shale is thereby saved. Moreover, raw or unburnt shale can be much more quickly
pulverized or ground to powder than burnt shale, and the latter dries with a dull
face whereas raw shale dries with a smooth or glossy face.
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 :-
The employment in the manufacture of plaster, of shale in its raw or unburnt
state mixed in about the proportions stated with hydraulic lime or other cement,
substantially as and for the purpose hereinbefore described.
Dated this 9th day of August 1892.
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicant.