Tiles and Pottery
with Color Magnesite
Cement Work
[Illustration]
MAGNESITE CEMENT WORK is a mixture medium producing a hard marble-like
quality and does not contain any Portland cement, but is given in this
book in order to complete the possible plastic mediums for the worker
wishing to mold objects with permanent durable mediums.
MAGNESITE CEMENT IS A SUCCESSFUL INDUSTRIAL MATERIAL and is used by
builders in interior trimmings for floor tiles, in making of bath-room
surfaces and recently used in coating stairways and hallways, producing
a pleasing texture and durable surface. The material is fireproof,
cleanly and better than marble.
MAGNESITE IS A FORM OF LIMESTONE and is a carbonate of magnesia which is
produced by burning until all gases have been eliminated, leaving only
the oxide in the form of a pure white powder. It comes from Europe and
is found in Maryland, Massachusetts, New York, Vermont, California, and
Washington. It has been used extensively in Europe and when better known
will be used more generally in America.
MAGNESITE CEMENT AS AN ENAMEL has been used as a hardening surface on
concrete and cement surfaces and also on clay brick. The concrete or
cement or brick surfaces should be thoroughly moistened before the
magnesite mixture is placed upon it to avoid the moisture from the
magnesite being absorbed and improperly drying.
THE MATERIALS FOR PRODUCING MAGNESITE are calcined powdered magnesite,
chloride of magnesia, sulphate of magnesia, white sand, white talc and
fine sawdust.
The magnesite should be kept in a container, proof against exposure to
air and dampness, in order to preserve its full setting qualities.
Chloride of magnesia has the appearance of ice or alum and when exposed
has the tendency to dissolve but does not deteriorate. It is the
chemical which when united with the magnesite produces the binding or
cement qualities.
Sulphate of magnesia or epsom salts is an easily secured material and is
used in very small quantities in the formulae for producing magnesite
cement and which is given later in this chapter.
The white talc or soapstone used for giving a smooth and polished white
background is used as a filler.
White sand and the fine sawdust should be absolutely clean and are mixed
with the other ingredients to produce the composite mixture to produce
Magnesite Cement.
TO COMBINE THE INGREDIENTS proceed as follows:
FIRST MIXTURE. Two and one-half pounds of powdered magnesite and one
pound of white talc are mixed thoroughly with one quart of fine sawdust.
To this mineral, dry color similar to that used and described for color
cement should be added if a color tone is desired. About one-half as
much color should be used as there is magnesite. In other words, one
pound of color should be used with two and a half pounds of powdered
magnesite. A stone mortar should be used to grind the entire mixture
well together.
This first combination is a dry mixture and is then mixed with the
second mixture which is liquid.
SECOND MIXTURE. Take five parts by weight of chloride of magnesia
solution with a density of 25 tested with a Baumé hydrometer which is a
simple glass tube secured at any druggist for registering solutions. To
the chloride of magnesia solution add one-half part by weight of
sulphate of magnesia which is epsom salts and test with the hydrometer
until it records 15.
TO USE THE HYDROMETER, place water in a container and if the hydrometer
is placed in it, it will register “0” and when the chloride is placed in
it, and dissolves the hydrometer will commence registering the density
of the solution. When it records 25 no more chemical should be added.
More water should be added to correct the density if needed. The same
procedure is followed for registering the 15 for the epsom salts.
Chloride of magnesia will dissolve more rapidly if it is broken up, and
distilled water may be used if the usual available water contains lime,
iron or other injurious minerals. Some workers use rain water for many
purposes.
THE FINAL MIXTURE, or third step in the mixing, is to take the first dry
mixture and add enough of the second liquid combination to produce a
thick creamy mixture of the two. Strain this after it has been well
mixed.
TO PRODUCE TILES OR OTHER OBJECTS, THE MATERIAL is quickly poured into
the molds. A brush may be used for brushing the material well into the
edges and corners. A gentle jarring of the mold will remove the air
bubbles and the molds with the magnesite is permitted to dry for seven
to ten hours before the cast is removed from the mold.
FOR VARIOUS COLORS in the same design, the dry mixture can be mixed with
color and the liquid, or second mixture, added to it. This can be
applied to the mold in the same way as the color was used with cement,
and after it has set, can be backed with a general color of magnesite
cement or with plain magnesite mixture.
TO FINISH MAGNESITE let it remain drying for two or three days after
which it can be washed with slightly warmed water to remove the thin
scum on the surface. A thin coating of beeswax or floor wax well
polished will finish the article.
[Illustration: The Making of Magnesite Cement]
[Illustration: Magnesite Objects Cast from Molds]
[Illustration]