IMPROVEMENTS IN COATING COPPER PRINTING PLATES TO RENDER THEM MORE DURABLE
Year: 1885

page_text: "
I, HERBERT MINTON-SENHOUSE of Stoke-upon-Trent in the County of Stafford
Director of Mintons Limited of the same place Pottery Manufacturer do hereby
declare the nature of my Invention for IMPROVEMENTS IN COATING COPPER
PRINTING PLATES TO RENDER THEM MORE DURABLE (a cominunication to me
from abroad by Henri Capelle of 350 Rue Saint Jacques Paris) to be as
follows:-
"
This invention has for its object improvements in coating copper printing plates
to render them more durable.
The depositing of nickel upon copper plate engravings for the purpose of making
them more durable has been done by others previously but for the more easy
removal of the nickel from the copper plate when partly worn and renickeling is
necessary a coat of iron is first deposited upon the copper in the usual and well
known manner and then the nickel is similarly deposited on the iron.

page_text: improvements in Coating Copper Printing Plates to kender
them More Durable.
I HERBERT MINTON-SENHOUSE of Stoke upon Trent in the County of Stafford
Director of Mintons Limited of the same place Pottery Manufacturer (a commu-
nication to me from abroad by Henri Capelle of 350 Rue Saint Jacques Paris)
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 :—
This Invention has for its object improvements in coating copper printing plates
to render than more durable.
The depositing of nickel upon copper plate engravings for the purpose of making
them more durable has been done by others previously but for the more easy
removal of the nickel from the copper plate when partly worn and renickeling is
necessary a coat of iron is first deposited upon the copper in the usual and well
known manner and then the nickel is similarly deposited on the iron.
The same improvement is applicable when other metals than nickel which are
not readily oxidizible are used for coating the plates as for example silver or
platinum.
In carrying out the invention I proceed as follows.
The copper plates to be plated are first placed in boiling Caustic Potash to loosen
the dirt from the face and out of the engraved parts of the plates, then scrubbed..
with a paste of tripoli mixed with nitric and sulphuric acid. They are then
suspended in a steel bath, opposite to a steel anode and with the ordinary
Bunson's Batteries, the steel is deposited on the plates.
The composition of the steel bath is as follows 1 lb of Sulphate of iron dissolved
in Gallon of hot water and 1 lb of Chloride of ammonium dissolved in Gallon
of cold water and mixed together. The plates should be removed from the bath
about every three quarters of an hour, and cleaned with a little flour of emery and
whitening. The time for leaving the plates in the steel bath varies according to
the class of work to be done; finely etched plates for example, would remain in
about three quarters of an hour, whereas a coarsely cut engraving would be in over
three hours, and it is purely a matter of judgment. When sufficient steel is
deposited on the copper plates, they are suspended in a nickel bath, and nickel
deposited on the steel by Bunson's Battery as before. The composition of the
nickel bath is as follows.
Double sulphate of nickel and ammonium 17 oz 13 dwts 16 grains.
Sulphate of Nickel
12
20
"
"
Boracic Acid
Sulphate of Magnesia
12
">
201
"
12
201
"
"
Carbonate
Liquid Ammonia
Water
12
"
201
"
1 oz 12
3
"
"
-
1 Gallons.

page_text: of Magnesia after being dissolved separately in hot water, should be added last.
When the mixture is withdrawn from the fire, the liquid ammonia is added. It is
most important that this bath should be filtered with filter paper. The length of
time the plates remain in the nickel bath is also a matter of judgment varying
from 20 minutes to 2 hours, according to the amount of nickel it is desirable to
have on the plates. It is of course particularly important that when the plates
require re-facing all the old nickel and iron should be removed, and for this
purpose all that is necessary is to place the plates in a pan containing a mixture of
Diluted Nitric acid in the proportions of 21 oz of nitric acid to 8 pints of water.
The acid works its way under the nickel dissolving the iron and shelling the
nickel off in flakes. This strength of acid readily dissolves the iron without in
anyway damaging the copper plate.
When the plates after being coated with iron are to be coated with silver or
platinum or other such like metal not readily oxidizable the composition of the
bath used for depositing such metal is varied according to the nature of the metal
to be deposited as will be readily understood by persons acquainted with the
means used for depositing such metals.
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. Coating engraved copper plates first with a coating of iron and then with a
metal not readily oxidizable substantially as described.
2. Coating engraved copper plates first with a coating of iron and then with
Nickel substantially as described.