AN IMPROVED PROCESS FOR COATING METAL WITH TIN
Year: 1878

page_text: LETTERS PATENT to Edward Parry, of New Bridge Street, in the City of
London, Iron Merchant, for the Invention of "AN IMPROVED PROCESS FOR
COATING METAL WITH TIN." A. communication from abroad by Ignaz
Neuburg, Josef Neuburg, and Moritz Böhm, all of the Firm of Neuburg & Co.,
of Vienna, Austria, and Berlin, Germany.
Sealed the 13th September 1878, and dated the 16th March 1878
PROVISIONAL SPECIFICATION left by the said Edward Parry at the
Office of the Commissioners of Patents on the 16th March 1878.
EDWARD PARRY, of New Bridge Street, in the City of London, Iron Merchant.
"AN IMPROVED PROCESS FOR COATING METAL WITH TIN." [A communication from
abroad by Ignaz Neuburg, Josef Neuburg, and Moritz Böhm, all of the Firm of
Neuburg & Co., of Vienna, Austria, and Berlin, Germany.]
The coating of metal plates or sheets with tin has hitherto been commonly
effected by dipping black sheets (sheet iron) of various dimensions and thickness
first into boiling grease or palin oil and afterwards into molten tin; but according
to my Invention the black plates are tinned without grease and without .molten
tio.
Tin plates made according to this Invention will not produce the injurious effects
resulting from the grease on ordinary tin plate, and which in many cases has led
to their disuse by manufacturers of potted provisions and others, and has caused
great inconvenience in cases where no convenient substitute can be found for such
tin plates, as in the manufacture of cans or tins for containing condensed milk.
In practising my Invention the black iron sheets of any desired dimension and
thickness are first well pickled by dipping them into a tank containing water, with
which is mingled sufficient sulphuric acid to give the liquid a density of 15 degrees
Baumé. If with the liquid of this degree the black surface of the said plates is
not readily removed, more sulphuric acid can be added to bring the pickle to a
density of about 20° Baumé. After this operation the black sheets are dipped into
clean water to remove all the acid therefrom, and are then scrubbed with the

page_text: ordinary brushes, sand mixed with dissolved quicklime being used to facilitate the
removal of dirt and acid from the surface of the plates. When this operation has
been thoroughly performed the sheets or plates are again washed with clean
water.
"
The next operation in my improved process is the subjecting of the sheets or
plates to a galvanic current produced either by "Bunsen or other batteries, or by
a magneto-electric machine.
The cleaned black sheets are suspended between tin anodes in a bath herein-after
described, and left under the influence of the batteries and bath for such time as
may be found necessary to deposit sufficient tin on the surface of the sheets. This
time will depend upon the quantity or thickness of tin to be deposited on each
sheet, and can be varied as to the quantity to be produced.
Great care must be taken in the preparation of the bath, which is composed of
distilled water, pyrophosphate of soda, protochloride of tin, and cream of tartar.
These materials are used in the following proportions, that is to say:-10 litres of
distilled water, in which are dissolved in the manner herein-after described 1 kilo-
gramme of pyrophosphate of soda and 125 gramines of protochloride of tin.
The dissolving of these ingredients is effected as follows:-The 10 litres of
distilled water are allowed to boil; then I pour into the same about a handfull of
the pyrophosphate of soda and dissolve it by continuous stirring with a glass rod.
As soon as the pyrophosphate of soda is dissolved.a part of the 125 grammes of
protochloride of tin is put into a fine brass sieve and suspended in the solution
of pyrophosphate of soda. The sieve must remain in the boiling water until the
protochloride of tin is thoroughly dissolved. This operation must be continued
until the whole of the 1 kilogramme of pyrophosphate of soda and the 125 grammes
of protochloride of tin are dissolved. This solution is emptied into the 100 litres
of distilled water in a wooden or earthenware vessel of square or oblong shape,
suitable for holding five or six sheets of black plates and the necessary anodes. If
larger quantities are to be tinned at the same time the bath must be enlarged in.
capacity, according to the quantity of liquid required therein.
Great care must be taken that the bath is always kept very clean, as dirt or dust
will spoil the effect of the deposit.
Cream of tartar is used only when the deposits shew a greyish instead of a
white color. In using the same I take 10 litres of the solution of chemicals above
described, and when the pyrophosphate of soda and protochloride of tin are dis-
solved I add the cream of tartar by dissolving the same through the brass sieve.
This solution is also poured into the bath.
'The black plates when dipped or immersed in the bath and connected with the
battery will readily coat with tin. After a few minutes the coated sheets are
removed from the bath and rubbed with brass wire brushes to give them a bright
appearance; then they are again dipped in clean water and placed in an oven.
If a very bright appearance is desired the sheets are subjected to the bath a
second time, and again rubbed with brass wire brushes, and when dry they can be
polished..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Parry in the Great Seal Patent Office on the 16th.
September 1878.
EDWARD PARRY, of New Bridge Street, in the City of London, Iron Merchant.
"AN IMPROVED PROCESS FOR COATING METAL WITH TIN." A communication from
abroad by Ignaz Neuburg, Josef Neuburg, and Moritz Böhm, all of the Firm of
Neuburg and Co., of Vienna, Austria, and Berlin, Germany.
The coating of metal plates or sheets with tin has hitherto been commonly"
effected by dipping black sheets (sheet iron) of various dimensions and thickness
first into boiling grease or palm oil and afterwards into molten tin; but according:
to my Invention the black plates are tinned without grease and without molteni
tin.
Tin plates made according to this Invention will not produce the injurious effect.
resulting from the grease on ordinary tin plate, and which in many cases has led
to their disuse by manufacturers of potted provisions and others, and has caused.
great inconvenience in cases where no convenient substitute can be found for such;
tin plates, as in the manufacture of cans or tins for containing condensed milk.
In practising my Invention the black iron sheets of any desired dimension and :
thickness are first well pickled by dipping them into a tank containing water, with:
which is mingled sufficient sulphuric acid to give the liquid a density of 15° Baumé.
If with the liquid of this degree the black surface of the said plates is not readily:
removed more sulphuric acid can be added to bring the pickle to a density of about
20° Baumé. After this operation the black sheets are dipped into clean water to
remove all the acid therefrom, and are then scrubbed with the ordinary brushes,
sand mixed with dissolved quicklime being used to facilitate the removal of dirt
and acid from the surface of the plates. When this operation has been thoroughly
performed the sheets or plates are again washed with clean water.
The next operation in my improved process is the subjecting of the sheets or
plates to a galvanic current, produced either by "Bunsen" or other batteries, or by
a magneto-electric machine.
The cleaned black sheets are suspended between tin anodes in a bath herein-after
described, and left under the influence of the batteries and bath for such time as
may be found necessary to deposit sufficient tin on the surface of the sheets. This
time will depend upon the quantity or thickness of tin to be deposited on each
sheet, and can be varied according to the quantity to be produced.
Great care must be taken in the preparation of the bath, which is composed of
distilled water, pyrophosphate of soda, protochloride of tin, and in some instances
cream of tartar. These materials are used in the following proportions, that is to
say: 10 litres of distilled water, in which are dissolved in the manner herein-after
described 1 kilogramme of pyrophosphate of soda and 125 grammes of protochloride
of tin.
The dissolving of these ingredients is effected as follows:-The 10 litres of
distilled water are allowed to boil; then I pour into the same about a handfull of
the pyrophosphate of soda and dissolve it by continuous stirring with a glass rod.
As soon as the pyrophosphate of soda is dissolved a part of the 125 grammes of
protochloride of tin is put into a fine brass sieve and suspended in the solution
of pyrophosphate of soda. The sieve must remain in the boiling water until the
protochloride of tin is thoroughly dissolved. This operation must be continued
until the whole of the 1 kilogramme of pyrophosphate of soda and the 125 grammes
of protochloride of tin are dissolved. This solution is poured into about 100 litres
of distilled water in a wooden or earthenware vessel of square or oblong shape,
suitable for holding five or six sheets of black plates and the necessary anodes. If
larger quantities are to be tinned at the same time the bath must be enlarged in
capacity, according to the quantity of liquid required therein.

page_text: Great care must be taken that the bath is always kept very clean, as dirt or dust
will spoil the effect of the deposit.
Cream of tartar is used only when the deposits shew a greyish instead of a white
color. In using the same I take 10 litres of the solution of chemicals above
described, and when the pyrophosphate of soda and protochloride of tin are dis-
solved I add about 125 grammes (more or less) of cream of tartar by dissolving the
same through the brass sieve. This solution is also poured into the bath.
The black plates when dipped or immersed in the bath and connected with the
battery will readily receive a coat of tin. After a few minutes the coated sheets
are removed from the bath and rubbed with brass wire brushes to give them a
bright appearance; then they are again dipped in clean water and placed in an
oven. If a very bright appearance is desired the sheets are subjected to the bath
a second time and again rubbed with brass wire brushes, and when dry they can
be polished.
By this improved process a uniform layer or thickness of tin can be deposited on
the tin plates.
Having thus fully described the said Invention as communicated to me by my
foreign correspondents, and the manner of performing the same, I wish it understood
that I claim,
First. The herein described method or process of tinning black iron plates, con-
sisting in first pickling the said plates, then removing the acid therefrom by
washing and scrubbing, then subjecting the said plates when suspended between
tin anodes in a bath or solution to a galvanic current, as and for the purposes
specified.
Second. The solution or compound consisting of distilled water, pyrophosphate
of soda, and protochloride of tin, with or without cream of tartar, these ingredients
being mixed or combined in or substantially in the proportions above specified.
In witness whereof, I, the said Edward Parry, have hereunto set my hand
and seal, this Twelfth day of September, in the year of our Lord One
thousand eight hundred and seventy-eight.
EDWARD PARRY