CERTAIN IMPROVEMENTS IN MAKING STEREOTYPE PLATES
Year: 1820

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARC
ISAMBARD BRUNEL, of Chelsea, in the County of Middlesex, Engineer, send
greeting.
WHEREAS His late most Excellent Majesty King George the Third did,
by His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-fifth day of
January, in the sixtieth year of His reign, give and grant unto me, the said
Marc Isambard Brunel, my exors, admors, and assigns, His especial licence;
full power, sole privilege, and authority, that I, the said Marc Isambard
Brunel my exors, admors, and assigns, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, during the term of years therein mentioned, my Invention of "CERTAIN
IMPROVEMENTS IN MAKING STEREOTYPE PLATES;" in which said Letters Patent
there is contained a proviso that if I, the said Marc Isambard Brunél, shall
not particularly describe and ascertain the nature of my said Invention, and
in what manner the same is to be performed, by an instrument in writing
under my hand and seal, and cause the same to be inrolled in His Majesty's
High Court of Chancery within six calendar months next and immediately

page_text: after the date of the said Letters Patent, that then the said Letters Patent,
and all liberties and advantages whatsoever thereby granted, shall utterly
cease, determine, and become void, as in and by the same (relation being
thereunto had) will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Marc Isambard Brunel, do hereby declare that the nature of my said In-
vention, and the manner in which the same is to be performed, are described
and specified in manner following, that is to say:
It consists in the means and methods which 1 adopt,-
First, for taking moulds from the original plate of types or woodcuts; and,
secondly, for obtaining the cast, or the printing plate, from the said mould.
As the various processes which are commonly practised in manufacturing
stereotype plates could not be rendered sufficiently expeditious to answer the
object I had in view, namely, that of multiplying printing plates for the purpose
of accelerating the printing of daily papers, I have, in order to attain that
desideratum, adopted the following means and methods in which my improve-
ments consist, and which are equally applicable to the making of stereotype
plates in general in an easy and expeditious manner. By the method in
question the mould is made by compression somewhat in the way that an
impression might be taken from types or woodcats by means of wax, and for
that purpose I make use of a suitable composition, but that which I prefer
consists of pipe clay 7 parts, chalk or burnt clay pounded very fine 12 parts,
and starch one part in bulk, not by weight. The whole being mixed with
water is made into a paste of the consistency of thick putty. In that state it
is fit to take an impression from types. and I accordingly use it as follows:
that is, I spread it over a metal plate, the size of which ought to exceed the
plate of types by half an inch at least. I adopt in preference a steel plate as
thin as a common tenon saw, which plate is perforated with small holes, say
1 of an inch diameter, and about half an inch apart from each other. The
composition and plate being so prepared the next process is the spreading of
the composition over the steel plate in such a manner as to afford a pro-
portionate supply to the different sizes of types, as well as to the distances and
vacant spaces. This is done by the following means, that is, the original
plate of types or woodcuts, or both together, from which a mould is intended
to be taken, must previously be well secured in a chace or galley. The
instrument I use being in form and character like a galley, I shall denominate
it a galley. The bottom part of the galley in question should be very flat, and
the whole very strong. The upper edge of the sides should be nearly on a

page_text: level with the surface of the types. The steel plate should be connected with
and adjusted to the galley by means of two centers acting like a hinge. The
plate may in that way act as the lid of a box, and may be brought down over
the surface of the types. These implements being so disposed, I proceed by
laying a sufficient quantity of the composition over the inner surface of the
steel plate, which I denominate the mould plate. I then spread a piece of
skin or parchment in a wet state over the surface of the composition. I
further lay over the surface of the plate of types a covering consisting of
several folds of thin calico or other suitable stuff stretched in a very light
frame. The mould plate thus covered with the composition, and with the skin
or parchment, is then laid down upon the surface covered by the calico, and
pressed or rubbed with some degree of force, so as to effect the distribution
of the composition over the mould plate: a roller passed several times over the
back of the mould plate answers very well for the purpose. The use of the skin
and other covering is to prevent immediate contact with the type plate while
the composition is forced to diffuse itself over the surface of the mould plate.
The excess of the composition oozes out partly at the sides, and partly through
the small holes perforated all over the mould plate. After this first operation the
composition on the mould plate exhibits all the prominent features of the impres-
sion. The skin and calico covering are then taken off, and in lieu of them I
substitute two leaves of thin paper, both over the type plate. The pressure is
then repeated until the impression appears more distinct. One of the two
leaves is then taken off from the surface of the mould to which they have
adhered and the pressure repeated. The last leaf is, stripped off in its turn,
and before laying the mould down the face of the types should be rubbed over
with a brush which has been slightly touched with oil. The mould plate is
then turned down again, and the composition now being in immediate contact
with the types receive by a gentle action that finish which is requisite to
obtain a perfect impression. The flexibility of the mould plate contributes very
materially to facilitate the operations. The thinner the mould is reduced by
the last action of rubbing or pressing the better, provided the thickness of the
composition which remains at the bottom of the letters is even and uniform.
It cannot, indeed, be too thin; it would even be desirable that the steel
mould plate should come in contact with the force of the types. The use of
the roller in producing the mould by compression might be done away with, and
the operations might be effected by means of a press similar to a printing
press; on the other hand the mould plate being flexible instead of its being
connected with and adapted to the galley by means of two centers acting like
an hinge, as has been specified before, might be applied to and fastened round

page_text: a roller, say 12. diameter, and four or five inches broad (these dimensions
may be very arbitary), in which case the impression would be obtained by either
sliding the galley under the roller, or by carrying the roller over the types
contained in the galley; in the first of which cases the roller should revolve on
an axis bearing on two standards, fixed on a bed proportional in its dimensions
to those of the galley. These two standards should be at such a distance from
each other, and the center of the axis should have the means. of being adjusted
sufficiently high to, admit of the galley being moved to and fro under the said
roller. The parrallelism of this reciprocating action should be maintained by
lateral guides fixed to the bed in question. The parts being so disposed are
ready to operate. The steel mould plate having been previously coated with
the composition, and covered with the skin or parchment, and the calico or
stuff covering having been laid over the types, the galley may then be brought
into action under the roller until the surface of the composition, which now
assumes the character of a cylindrical mould, exhibits the prominent features
of the impression; the excess of the composition oozes out at the sides, or is
pressed out by the revolving action of the roller. The skin or parchment and the
other coverings are next to be removed, and replaced by the two leaves of thin
paper, as has been stated before, and when after repeating the action of the
galley, the impression appears as deep and as distinct as is required, the paper
leaves are stripped off in succession. The composition is now brought in contact
with the types, which are to be previously brushed over, as has been described.
before, and in that state the reciprocating movement of the galley is repeated,
and the roller adjusted at the same time, until the impression is as deep and as
perfect as is required. It is necessary to observe, that in order to insure the
whole effect, which should result from this mechanical arrangement, the roller
and galley are to be connected together by means of a wheel with teeth and
a rack. The wheel is to be fixed on one extremity of the roller, and the rack
fitted and adjusted to one of the edges of the galley, so as to com-
bine their respective action. It is easy matter to understand how the action
may be reversed, so as to effect that which is adverted to in the second case,
namely, that of carrying the roller over the types contained in the galley; the
axis of the roller should extend at both sides and terminate into two handles.
A tooth wheel of a fine pitch is to be adapted to each flat end of the roller,
and meet with a rack of a corresponding division, fastened, on each edge of the
galley. The lateral action of the roller is to be confined by means of two
flanches extending beyond the diameter of the tocthed wheels. The roller so
disposed may be rolled to and fro over the face of the types with ease and pre-
cision. The mould plates being fastened round it, as has been said before, every

page_text: other successive operation connected with the various coverings and with the
types being attended to, an impression may be obtained by this method in as per-
fect a manner as may be required. And after having effected it as directed in
this as well as in the first case, the mould plate is taken off from the roller, and
as it returns to a plain surface, it produces a flat mould, which was the object
anticipated from either of these two modes. A mould taken by, either of the
methods herein specified is easily dried by exposure to the air, or by a
moderate heat in a stove, which heat should in no instance exceed 500°. The
mould is by that means ready prepared in a very expeditious way to receive
the metallic composition of which the stereotype plate is intended to be made.
And in order to obtain the cast, I proceed as follows: that is to say, the mould
plate is placed with the face upwards in an instrument resembling a tray, which
I accordingly denominate a tray, of dimensions fit to hold the steel mould
plate. The sides of the tray are about one inch high, and the bottom
is open in holes of about one inch in diameter as close as possible. These
apertures are intended to admit water or other fluid, which is injected for the
purpose of cooling the mould plate. The metallic compound of which the
stereotype is to be made may be same as used in the ordinary way; but when
expedition is an essential point, I take in preference the well known alloy,
consisting of bismuth 10 pounds, lead 6 pounds, and tin 4 pounds, which
alloy is heated to about 400°. When the cast is to be obtained I proceed as
follows; that is, I place the mould plate in the tray with the face of the mould
upwards. I then apply above the surface of the mould plate a thick plate of
cast iron, say of an inch in thickness. This plate, which I intend to regulate
the thickness of the stereotype plate, is disposed in manner following:-First,
this regulating plate must be of dimensions corresponding exactly with the
size which the stereotype is to be. Its four sides must have prominent edges
projecting from the surface as much as the thickness which is to be given to
the stereotype plate. At each corner of the regulating plate there is an
adjusting screw intended to support it in its place. I then place this plate
with the prominent edges downwards over the mould plate, taking care that
it corresponds with its outlines both in breadth and length. This regulating
plate rests then upon the four adjusting screws. The tray being so disposed
requires to be heated to about 200° before the metal can be poured in.
now proceed by pouring a sufficient quantity of fluid metal into the tray. The
metal makes its way round and under the regulating plate, which may be
raised by hand if required. I immediately inject, by means of a flexible
pipe connected with a small reservoir of water or other fluid, a sufficient
quantity of such water or other fluid through the apertures at the bottom of
I

page_text: the tray, which strikes the bottom of the mould plate, and cools the metal
in it. This is productive of a good effect although the thickness of the
metal in fusion is but very inconsiderable. The cast is soon ready to be
removed, and while it is still hot the extra metal round the regulating plate
breaks off almost of itself, leaving the stereotype plate of its proper dimensions.
The composition is then washed off, and the plate may be considered to be
fit for the press, and it is blocked up as may be required. This I do by
having plates of proper sizes and thickness, over which the stereotype plates
are fixed by means of wax hardened with some rosin. As it is very desirable
to have a great pressure of metal when the finest casts are to be obtained,
in these cases I proceed in the following manner; that is, I place the
tray with the mould plate and regulating plate in a metal chamber which
can be hermetically closed. The chamber I make use of is a cast-iron
cylinder placed horizontally, closed at one end, and having a moveable door
plate so constructed as to be capable of instant application, and of great
resistance. On the upper part of the chamber there is a small orifice
destined to admit the metal into the chamber. The chamber is connected by
means of a pipe furnished with a stopcock to a vessel in which air has i
been condensed to a sufficient degree. I also adapt to this chamber a
small forcing pump intended to throw in through the under part water
or any other cooling fluid. The chamber being so disposed and fit to
receive the tray and mould plate, is prepared for ordinary use. I proceed
as follows; that is, I enclose the tray with its contents, which have been pre-
viously heated, in the chamber, which is immediately shut up, and I pour
the metal through the orifice, which should be instantaneously stopped herme-
tically. The metal soon makes its way under the regulating plate and
spreads itself over the surface of the mould. I immediately open the
communication with the condensed air, which produces the effect of a head
of metal, and I inject water, or other cooling fluid, for the purpose of
setting the metal in the cavities of the mould. Having the advantage of a
chamber, which admits of being hermetically closed, I can make use of it to
obtain first a vacuum, a method which has been, I understand, practised by
others, but not in connection with nor immediately followed by the expansive
power of condensed air, which is productive of the best effect, and which, when
coupled with the means of cooling the metal, must accelerate very materially
the manufacture of stereotype plates in general. As the mould plate retains,
even after it is completely dry, a sufficient degree of flexibility to admit of the
mould being shaped into segments or portions of a cylindrical form, and would
produce in this manner stereotype plates corresponding with that form, I

page_text: propose effecting this if it should be required by having a box of cast iron, of
a depth exceeding by at least one inch the breadth of the mould plate, the
sides of which would be formed to a given radius, and lay parallel with each
other, and no farther apart than is necessary for the stereotype plate. The
mould plate being placed in it edgewise, and the back being forced against the
concave side of the box, the metal may then be poured in, and the stereotype
plate will be found, when cooled and set, shaped to the given radius, or nearly
SO. It is necessary to heat the box before the metal is run in it.
It is an easy matter to conceive that the means and methods I have
herein described are susceptible of being modified, and may even be accom-
plished by a variety of ways; but as the nature and originality of my improve-
ments consist in, first, taking from the original plate of types moulds which
are calculated to answer my purpose, and, secondly, for obtaining a cast from
the said moulds, I have confined my Specification to a description of those
means and methods which I have found to answer best in practice, considering
that expedition is a most essential point to be attended to. I shall, however,
add, that a plate, possessing all the properties of a stereotype plate, may be
made in a very perfect manner by a kind of metal plating laid over a sub-
stance of the nature of japan or of thick varnish. And for this purpose I take
some shell-lac, and having melted it. I spread it over an iron plate of an inch,
or thereabouts. in thickness. This coating is hardened by exposure to heat,
until it acquires a consistency sufficient to oppose some resistance in the
mould. I immerse the plate so coated in type metal in fusion. just as is
practised in the operation of tinning. The plate comes out tinned as it were
all over the coated surface, and as this substance retains its heat for a sufficient
time, the metal coating remains also in a fluid state so long as the heat con-
tinues above the melting point. I then apply the metal plate to the mould
plate, and press both together. The mould piate should be previously heated
to a degree somewhat below the melting point of the type metal employed.
The plate and mould are left to cool under the press. The impression thus
obtained is remarkably perfect. The same plate may be made to take another
or several successive impressions, by repeating at each time the immersion
into, type metal, and proceeding as stated before. This mode of obtaining
stereotype plates is very expeditious, and may prove of great benefit.
In witness whereof, I, the said Marc Isambard Brunel, have hereunto
set my hand and seal, this Twenty-fifth day of July, in the year of our
Lord One thousand eight hundred and twenty.

page_text: AND BE IT REMEMBERED, that on the Twenty-fifth day of July, in the
year of our Lord 1820, the aforesaid Marc Isambard Brunel came before our
said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified,, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Inrolled the Twenty-fifth day of July, in the year of our Lord One
thousand eight hundred and twenty..