An Improved Manufacture of Electrotype Printing Blocks.
Year: 1895

page_text: Date of Application, 5th July, 1895-Accepted, 17th Aug.;
1895
An Improved Manufacture of Electrotype Printing Blocks.
A communication from LOUIS BOUDREAUX, of 42 Boulevard Bonne Nouvelle,
Paris, in the Republic of France.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent; '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:-
Galvanoplastic reproductions for printing are generally made, from impressions
in wax, guttapercha or some other plastic matter the surface of which is made a
conductor by coating it, with pulverized graphite or plumbago.
As regards more especially galvanoplastic reproductions in nickel, the small
amount of adhesion of this metal. to the coating of plumbago often causes the nickel
to detach itself from the impressions.
"
In order to remedy this serious drawback the idea has been conceived of metal-
lizing the surface of the wax or other plastic material, before the impression is made
instead of coating it in the ordinary manner with a coating of graphite or
plumbago.
In order to metallize these surfaces of plastic material all suitably pulverized
metals may be employed. Practically a coating of pulverized bronze is applied on
the surface of the wax plates before the taking of the impression. The bronzing
of the wax plates may be effected in various ways; the important thing is to make
the powdered bronze adhere as perfectly as possible. This is easily done by rubbing
the surface of the wax by means of suitable brushes impregnated with the powdered
bronze. This friction causes a slight elevation of temperature which produces the
adhesion of the powdered bronze to the wax.
A more perfect result is obtained by sprinkling the wax surface with the
powdered bronze, but with the essential condition that this operation must be
performed immediately after the casting of the wax plate before its solidification.
The tenacity of the powdered bronze is so great that the grains of this powder
remaining on the surface of the liquid wax establish themselves thereon and almost
instantaneously cover the whole surface without interruption; when the wax has
become solid by cooling the excess of powdered bronze may be easily removed.
by any suitable means.
The plates of wax or any other plastic matter thus metallized are then applied
by pressure to the objects to be moulded by following the moulding processes
inherent to the materials employed.
In order to fix the metallic powders on the surfaces of plastic substances which
become soft without melting, as for example guttapercha, these surfaces must be
previously heated. The same result may be attained by means of repeated friction
by using harder brushes than for wax. The heat developed by this friction will
make the guttapercha adhesive and ensure the perfect fixing of the powdered metals.
The metallic powders may also be made to adhere to the surfaces of all plastic
substances by coating the latter with a suitable solvent and then projecting the
said metallic powders on to the surfaces thus prepared; after evaporation the
excess of powder is removed by any suitable means.
It follows from the experiments made with a view to obtaining this Patent that
as regards more especially nickel, the adhesion of this metal to the metallic coating

page_text: obtained in the manner above set forth is sufficiently great to prevent it from
becoming detached from the impression. Furthermore a surface of wax or any
other plastic matter thus metallized is a much better conductor than a plumbago
surface, and any metal whether nickel or other kind deposits itself thereon with
greater rapidity.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is;-
The above described process of metallization of the surfaces of plastic materials
such as wax guttapercha etc. used for galvanoplastic reproductions "clichés " or
the like in any kind of metal by applying to these surfaces before taking the
impression and by any suitable means metallic powders (powdered bronze or other
metals) this metallization being performed instead and in the place of the ordinary
application on the same surfaces of powdered graphite or plumbago substantially
as and for the purpose described.
Dated this 5th day of July 1895
BOULT & WADE,
Agents for the Applicant."