IMPROVEMENTS IN AND CONNECTED WITH THE MANUFACTURE OF ELECTRO-TYPES
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by James Noad at the Office of
the Commissioners of Patents, with his Petition, on the 18th
December 1872.
I, JAMES NOAD, of Hackney Wick, in the County of Middlesex,
Engineer, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN AND CONNECTED WITH THE MANUFACTURE OF ELECTRO-TYPES," to
be as follows:—
The first part of my Invention consists in the employment of a new
material or of a composition of materials which I use in connection with
the manufacture of electro-types as follows:-To a pound of lead when
melted and at a temperature of or about 720 degrees Fahrenheit, I stir
in with it about one quarter of a pound of roll sulphur, and continue to
stir the mass till it ceases to shew any sign of flame, afterwards when
cold it is ground by stones or in any other convenient manner and bolted
or sifted as fine as possible and to an impalpable powder, the residuė
being reground.
The above mixture is mixed by means of a masticator with about one
third of its weight of gutta percha, or india-rubber, or other similar or
equivalent suitable material such as gelatine or wax blended or mixed

page_text: up with oils or other suitable material, as may be found necessary, which
is kept soft by dry heat.
The above material is used to form the moulds on which the electro
deposition is made.
To render it available for copying type or wood cuts for example I
mill the material by passing it between rolls or by pressure until reduced
to about one sixteenth of an inch in thickness, I then brush it over
with black lead by means of an ordinary brush, black lead taking much
more readily to this prepared material than to gutta percha, it is then
warmed or softened by water or by any other means and is pressed on
the type in the ordinary way.
When cold the black lead causes the material prepared in the manner
before described to very readily leave the type both clean and true, it is
then ready to be wired and put into the copper or other bath or if it is
wished to hasten the process the mould as above prepared is then put
into a lead bath of sugar of lead and water as hereafter described, and
worked by the battery for about ten minutes in the ordinary way. The
lead in the moulds causes the lead to instantly take all over the mould,
and thus the deposition of the copper or other metal is materially
expedited. The mould is then washed and put into a copper bath
whereby the copper is deposited thereon in the ordinary way by a Bunsen
or Grove battery. As soon as the deposit of copper is thick enough,
which takes about an hour and a half, it is laid on a true slab solutioned
with chloride of zinc, and backed in the ordinary way with type metal..
for example, whereby no buckling takes place before it is stripped, it is
then mounted (after being stripped from the mould) in the ordinary way,
or if the greatest possible dispatch is required the prepared sheet is
slightly warmed by dry heat, and a sheet of tin foil preferably thin is
evenly laid on it and attached thereto by gentle rubbing. When
required for use the sheet thus tinned is softened as before described, laid
tin downwards on the work, and moulded as before described. This
having a thoroughly conducting surface needs no guiding wires but
becomes almost instantaneously coated with copper, the moulding com-
position at the back being also conducteous or of a conducting nature,
the electro copper not only attaches itself to the tin surface, but:
penetrates it, apparently cutting out the impurities of the tin foil, and
absorbing the pure tin. By this means the deposit is sufficiently thick
in about half an hour. to be backed as herein-before described..

page_text: The sugar of lead and water bath before mentioned is composed of a
saturated solution of sugar of lead, this gives a white fluid which is
filtered, the part filtered off being the white lead of commerce. This is
the lead solution of the Pharmacopeia.
My Invention further consists in giving a true face to electro-types
on both sides known as surfacing in the following manner:—I take
any mould but preferably prepared with the material before described,
and place it into a sulphate of copper bath containing of or about seven
per cent. of free acid, this bath is worked with a large "anode"
(dissolving plate preferably pierced) with a small low power battery, and
is rubbed continuously or intermittently during the deposition with a
fine camel hair brush, thereby preventing all roughness and makes the
work perfectly true.