Improvements in the Manufacture of Moulds and the Taking of Matrices for Stereotype Plates.
Year: 1887

page_text: Date of Application, 7th June, 1887
Complete Left, 5th Apr., 1888
Complete Accepted, 11th May, 1888
Improvements in the Manufacture of Moulds and the Taking of
Matrices for Stereotype Plates.
[ GEORGE EASTWOOD, of 42 Whitefriargate, in the Town or Borough of Kingston
upon Hull, Newspaper Manager, do hereby declare the nature of this invention to be
as follows:
In the ordinary method of manufacturing moulds or taking matrices for stereotype
plates the moulds are made of a pulpy combination of adhesive substances with
blotting or other papers which absorb a large quantity of moisture. These moulds
are beaten or rolled into the type so as to take a matrix thereof; the type is then
heated in order to dry the mould. Much time is lost in the drying operation but it
cannot be avoided when this method is followed because if the mould is not sufficiently
wet the face is liable to crack or break and a perfect impression of the type is not
obtained.
Now according to my invention I follow what is practically a dry process, and the
heating of the type can be dispensed with. I make the mould of two parts, namely:
a facing and a backing. The facing is composed of a piece of muslin or other suitable.
thin textile material covered with a sheet or sheets of tissue paper or other like
material; the muslin is soaked with, and the paper (when more than one sheet is
used) is pasted with, a composition which will keep the muslin in a flexible state,
prevent the paper from drying hard before use, render it sensitive to moisture,
prevent contraction on application of heat and harden the facing when heated. The
composition which I use for this purpose is formed of glycerine and starch with or
without a small quantity of common salt, suitable proportions of which are about six
ounces starch, one ounce glycerine, and twenty grains salt.
The backing consists of a dry thick sheet of soft paper, blotting paper, felt or other
like suitable substance capable of receiving and retaining an impression.
The facing composed of the muslin and tissue paper is dried cold and when used
should contain only sufficient moisture to render the paper slightly soft.
The muslin
should be kept firm and wiped with a sponge containing the composition.
In taking the matrix the facing is placed upon the type, paper side downwards, and
the backing of dry paper is placed upon it. They are then covered with woollen or

page_text: india-rubber blanketting and rolled or pressed. The matrix is at once formed and
when removed from the type bas simply to be warmed through. The heat quickly
sets the composition and hardens the face.
The muslin, the dry backing and the composition constitute special features of my
invention. The muslin prevents the bursting or cracking of the paper when pressed;
the glycerine and starch keep the muslin in a flexible state, the glycerine prevents
the tissue paper from drying hard before use and makes the facing sensitive to
moisture and also prevents contraction on the application of heat while the starch
hardens the facing when heated, and the salt and glycerine prevent the liability of the
facing to curl.
TY
11
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1007
J. C. MEWBURN,
169, Fleet Street, London,
Agent.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Moulds and the Taking of
Matrices for Stereotype Plates.
I, GEORGE EASTWOOD, of 42 Whitefriargate, in the Town or Borough of Kingston
upon Hull, Newspaper Manager 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 :-
In the ordinary method of manufacturing moulds or taking matrices for stereotype
plates the moulds are made of a wet or pulpy mixture of adhesive substances with
blotting or other papers which absorb a large quantity of moisture. These moulds
are beaten or rolled into the type so as to make a matrix thereof; the type is then
heated in order to dry the mould; if the mould is not dried or partly driod while in
contact with the type the impression becomes distorted by contraction of the mould.
Time is lost in the drying operation but this cannot be avoided when this method is
followed because if the mould is not sufficiently wet the face is liable to crack or
break and the impression of the type is in such case unfit to take a casting from.
Now according to my invention I follow what is practically a dry process in the
manufacture of the moulds or matrices so that the heating of the type in order to
dry them can be dispensed with while they are ready for the casting box in a much
shorter time than when the ordinary or wet method is followed.
For the purpose of my invention I make the mould or matrix of 2 parts, viz.: a
facing and a backing. The facing is composed of 2 or more sheets of tissue paper

page_text: or other like thin paper united by means of a mixture of glycerine and a suitable
starchy material with or without gum; the mixture keeps the paper in a flexible and
elastic state, prevents it from becoming too hard before use, renders it sensitive to
moisture, greatly reduces the contraction on application of heat and hardens the
matrix or mould when heated. The mixture which I preferably use for this purpose
is formed of glycerine, starch and gum arabic or other gum suitable proportions of
which are:-1 lb. of starch, 2 fluid ounces of glycerine, and 2 or 3 oz. of gum, sufficient
water being of course used to make the mixture when boiled, into a thick paste; the
object of the gum is to give increased stiffness to the mould; its use although desirable
is not of great importance and is therefore optional. The facing should be dried cold
under a light pressure and when used should contain only sufficient moisture to render
the paper slightly soft.
The backing which forms the bulk of the mould consists of one or more dry thick
sheets of soft paper, blotting paper, felt or other like suitable substance capable of
receiving and retaining an impression, and one side of it is covered with a thin sheet
of soft paper which is thinly coated on both sides with an adhesive material preferably
of the nature and possessing the properties of the mixture herein before described.
Or the thin sheet of paper can be dispensed with and the mixture be applied directly
to the face of the backing. The mixture serves to unite the backing to the facing
when pressed together as hereinafter described.
In taking the matrix the facing which as already explained should contain only
sufficient moisture to render the paper slightly soft is placed upon the type and the
back of the facing is then covered, first, with a piece of muslin or other suitable thin
textile material and, next, with a woollen or india rubber blanketting which (except
when of indiarubber) is preferably used warm; the whole is then rolled or pressed.
This having been done the blanketting and the muslin are removed and then the dry
backing is placed upon the back of the tissue paper that forms the facing, that face of
the backing which bears the mixture being put in contact with the tissue paper; the
mixture on the backing should be nearly dry. The blanketting is placed upon the
backing and the whole is again rolled or pressed. The matrix is at once formed and
when removed from the type has simply to be warmed through to harden the
mixture. Instead of the 2 rollings or pressings above described one rolling or
pressing will suffice if the backing be placed upon the facing in the first instance with
the blanketting over them, but a good result is not so certain; the use of the muslin
may in this case be dispensed with. Further instead of using muslin or other thin
textile material as a separate or loose piece it may form the back of the facing by
being attached by means of the mixture to the back of the sheets of tissue paper.
In order to warm the matrix and render it quite dry and thereby harden the mixture
any suitable method or apparatus may be adopted. I have found it sufficient to place
the matrix upon hot sand for about a minute.
In some cases more particularly for small moulds or matrices. taken from solid
formes, that is to say, formes not containing large blanks I find that a single sheet
of tissue paper is sufficient for the facing that side of it which is not to come in
contact with the type being coated with the mixture and in such case the facing must
not be rolled or pressed without the backing. Or if the face of the backing be coated
with the mixture the tissue paper may be uncoated. Or the tissue paper which is to
form the facing may be united to the backing by means of the mixture with or without
a piece of muslin between before being placed on the type.
The use when containing little moisture of a facing of tissue paper in combination
with the mixture described, the mounting of this on a thick dry backing and the
use of muslin or other thin textile material in contact with the back of the facing
during the rolling or pressing process, constitute special features of my invention.
The glycerine and starch increase the strength of the facing and render it soft and
flexible the glycerine prevents contraction when the sheets are drying and on the
application of heat and causes the starch to adhere to the paper notwithstanding
the heat while the starch hardens the matrix when heated.
The muslin prevents
the bursting or cracking of the paper when being rolled or pressed.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
1. The use in the manufacture of moulds or taking of matrices for stereotype
plates, of a facing composed of one or more sheets of tissue paper or other like
thin paper, united together when there are two or more sheets by means of, or
coated at the back when there is only one sheet with, a mixture of glycerine and
a starchy material with or without gum the said facing containing at the time of
such use only sufficient moisture to render the paper slighly soft, substantially as and
for the purpose set forth.
2. The use in the manufacture of moulds or taking of matrices for stereotype
plates of a facing and a backing, the facing being composed of tissue paper or
other like thin paper, united together in the case of more than one sheet by means
of, or coated at the back in the case of a single sheet with, a mixture of glycerine
and a starchy material with or without gum the said facing containing at the time
of such use only sufficient moisture to render the paper slightly soft, and the
backing being composed of one or more dry thick sheets of soft paper, blotting
paper, felt or other suitable substance capable of receiving and retaining an
impression, all substantially as set forth.
3. In the manufacture of moulds or taking of matrices for stereotype plates, the
use of muslin or other suitable thin textile material in contact with the back of
the facing while the facing is being rolled or pressed, as and for the purpose set
forth.
4. In the manufacture of moulds or taking of matrices for stereotype plates, the
process herein before described which consists in laying upon the type a facing
composed of sheets of tissue paper or other like paper united by means of a mixture
containing glycerine and a starchy material the said facing containing only sufficient
moisture to render the paper slightly soft, in then covering the back of the facing with
a piece of muslin or other thin textile material and with a blanketting, in then
submitting the whole to rolling or pressing, in then removing the blanketting with
or without the muslin, in then placing upon the facing a backing consisting of one
or' more dry thick sheets of soft paper, blotting paper, felt or other suitable
substance capable of receiving and retaining an impression, that side of the backing
which is next the facing having a coating of adhesive material, in then laying
blanketting upon the backing, and in then submitting the whole to rolling or
pressing whereby a matrix is formed, all substantially as set forth.
5. My improvements in the manufacture of moulds or the taking of matrices for
stereotype plates, substantially as hereinbefore described.
Dated this Zih law of 1000
J. C. MEWBURN,
169, Fleet Street, London,
Agent.