Improvements in the Manufacture of Plaster.
Year: 1892

page_text: Date of Application, 26th July, 1892
Complete Specification Left. 25th Apr., 1893-Accepted, 27th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Plaster.
1 JOHN CALDWELL BLOOMFIELD of Castle Caldwell, Leggs, in the County of
Fermanagh, Ireland, Gentleman, do hereby declare the nature of this invention
to be as follows:-
The object of this invention is to manufacture plaster which is lighter in weight
In the manufacture of
and is less expensive, than the plasters at present in use.
my improved plaster I first prepare a special lime consisting of ordinary hydraulic
lime with about five per cent. of gypsum added. I then intimately mix equal
parts of this specially prepared lime and sawdust, and sift them through a sieve of
suitable mesh. This compound when mixed with water and applied in the ordinary
manner for coating walls and partitions of houses will set quickly and firmly and
will have a fine surface. The sawdust will serve to bind the particles of the lime
together in place of the hair and sand as ordinarily used, and, as the sawdust is
lighter in weight than the hair and sand, the finished product will be less heavy,
and therefore less likely to fall or crack than ordinary plaster coatings for ceilings
and will go over a greater area.
The compound may also be used for making ornaments, figures, moldings, and
the like.
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Plaster
I JOHN CALDWELL BLOOMFIELD of Castle Caldwell, Leggs, in the County of
Fermanagh, Ireland, Gentleman, 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 which is lighter in weight
and is less expensive than the plasters hitherto used.
I
In the manufacture of my improved plaster I first prepare a special lime
consisting of ordinary hydraulic lime with about 5 per cent. of gypsum added.
then intimately mix this specially prepared lime with about an equal part by
measure of sawdust, and sift them through a sieve of suitable mesh.
The percentage of the various ingredients in the compound is about as
follows
This compound when mixed with water and applied in the ordinary manner for
10 ceilings, walls and partitions of houses, will set quickly and firmly. The sawdust
will serve to bind the particles of the hydraulic lime and gypsum together in place
of the plastering hair usually employed for the binding in ordinary plasters. To
make a satisfactory plaster the plastering hair requires to be very carefully mixed

page_text: with the lime and sand or the plaster will crumble away after hardening and as I
entirely dispense with hair in my plaster, I avoid this trouble of mixing, and also
decrease the liability of the finished plaster to crumble or break away. Moreover,
as the sawdust is very cheap it is used in my plaster as a filling material in place
of sand and being lighter in weight than sand, the finished product will be less
heavy and therefore less likely to fall or crack from its own weight, than ordinary
plaster coatings for ceilings. It can also be spread out thinner and thus made to
cover a larger area. The compound may also be used for making ornaments,
figures, moldings, bricks or briquettes and the like purposes to which plaster is
applicable.
To render this plaster fireproof when so desired add a small quantity of
tungstate of soda to the water with which the special lime and sawdust are mixed,
say about 1 lb. of tungstate of soda to 100 gallons of water. In place of or in
addition to the tungstate of soda I may use sulphate of zinc or other fire resisting
material or materials for the same purpose and may incorporate the same with
the mixture of special lime and sawdust in any suitable and well known manner.
I am aware that it has been already proposed to make plastering compounds of
sawdust and plaster of Paris with the addition of hair or sand and some other
substance or substances, but the plaster compound made according to this invention
is confined to the mixture of hydraulic lime, gypsum and sawdust in about the
proportions stated.
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 :-
A plastering compound composed of about equal parts by volume of sawdust and
a special lime consisting of hydraulic lime with about 5 per cent. of gypsum added
thereto substantially as described.
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicant.