An Improved Moulding Material for the Production of Metal Castings.
Year: 1889

page_text: Date of Application, 28th May, 1889-Accepted, 20th July, 1889
COMPLETE SPECIFICATION.
An Improved Moulding Material for the Production of Metal
Castings.
I ALFRED CLAYTON COLE of the firm of W. H. Cole and Company of 85 Grace-
church Street in the City of London Merchants do hereby declare the nature of this
invention which has been communicated to me from abroad by Charles Henry
Wilder of Natick in the County of Middlesex and State of Massachusetts United
States of America Gentleman and in what manner the same is to be per-
formed to be particularly described and ascertained. in and by the following
statement:-
This Invention consists in an improved material or substance to be used for the
formation of moulds from which to cast articles of metal.
The object of this said invention is to produce a composition or material for this
purpose such that it will not be fused or fluxed by contact with the molten metal ;
but will, at all times, have, and preserve, a smooth and indestructible moulding face,
so that more perfect castings can be obtained from it than has heretofore been
possible by the use of the moulding sand or other materials commonly employed for
the purpose.
The improved moulding material constituting this Invention consists of a
mixture of pulverized coke and pulverized graphite or as it is commercially called
plumbago."
"
In preparing this mixture the said coke and graphite are ground to as fine a
powder as is readily practicable, the graphite, as is well known, being capable of being
reduced to a considerably finer degree than is the coke. After the two substances
have been thus ground they are united or incorporated with a suitable cokable binder
such as pitch. This binder is made plastic by heat and then it and the pulverized
coke and graphite are mixed together. The mass thus formed is then enclosed within
a suitable case and heated in a furnace to a sufficient temperature and for a sufficient
time to coke the binder. When this has been done and the mass has cooled it is
pulverized to the required degree of fineness substantially that of moulding sand.
The powder or sand thus obtained can be used like ordinary moulding sand but with
greatly improved results. The function of the coke in the mixture thus formed is
that which comes from its refractory and infusible character. The function of the
graphite is also that which comes from its refractory character, and, as is well known,
through its capacity, by reason of its relatively greater fineness of grain, to fill up
The function of
and permeate the interstices that occur among the grains of coke.
the binder is to bring about the union of the coke and graphite in a homogeneous
compound of equally refractory and infusible nature throughout, which, without the
use of such a binder, could not be practically united.
The said improved mixture possesses a more compact texture or grain and
consequently a greater capacity for exactly preserving and reproducing the form of
the article to be cast than would be possible if powdered coke alone were employed.
Inasmuch however, as the graphite is more costly than the coke, no more of it should,
in practice, be introduced into the mixte than is necessary to give to it the
improved qualities above set forth.
In practice it has been found that good results are obtained by using graphite in
the proportion of about one-fourth or one-fifth of the whole mass of the mixture, but
the proportion will be found to vary according to the class of work for the production
of which the moulding, material is to be used.
Enough of the binding material should be employed to thoroughly unite the mass.
It has been found in practice that it is desirable to employ the binder in such
proportion as to give to the whole mass, before coking, substantially the consistency
of mortar for brick laying.

page_text: The mixture of coke graphite and binder hereinbefore described may be used in
the same manner as common moulding sand is now employed and is intended to
serve as a substitute therefor.
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 :-
An improved moulding material consisting in a composition of matter comprising
coke, graphite and a coked binder in a loose granular form as hereinbefore set
forth.
J. H. JOHNSON & Co.,
Agents.