IMPROVEMENTS IN THE MANUFACTURE OF TIN PLATE, AND IN THE TINNING AND FINISHING OF SUCH PLATES OR OF TINNED ARTICLES, AND IN MACHINERY OR APPARATUS TO BE USED THEREWITH
Year: 1881

page_text: LETTERS PATENT to William Elmore, of 91, Blackfriars Road, in the County
of Surrey, Electrical Engineer, for an Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF TIN PLATE, AND IN THE TINNING AND FINISHING OF
SUCH PLATES OR OF TINNED ARTICLES, AND IN MACHINERY OR APPARATUS
TO BE USED THEREWITH,”
PROVISIONAL SPECIFICATION left by the said William Elmore at the
Office of the Commissioners of Patents on the 8th June 1881.
WILLIAM ELMORE, of 91, Blackfriars Road, in the County of Surrey, Electrical
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF "TIN PLATE,' AND IN THE
TINNING AND FINISHING OF SUCH PLATES OR OF TINNED ARTICLES,' AND IN
MACHINERY OR APPARATUS TO BE USED THEREWITH.”
.
This Invention relates to improvements in the manufacture of "tin plate," as
such is known in the "tin plate trade," that is, the tinning or coating with tin of
the body plates of sheet fron, and in finishing such plates with a lustrous and
polished surface, and in machinery to be employed in such improved manufacture,
the Invention being also applicable for use in tinning or coating with tin other
metallic articles (other than sheets), the object of the Invention being to reduce to
practice the tinning of the plates or articles by electro-deposition of the metal in
contra distinction to the old process of dipping the plates into cauldrons of molten
metal for tinning the same.
a
In carrying out the Invention I take what are known as "black plates” which
have been pickled," annealed, cold rolled, and finally "pickled" preparatorily to
being tinned. These plates having been freed from oxide in the final pickling and
Scouring and present a chemically clean surface, are now immersed and rinsed in a
tub of clean water or which may contain a little potash or cyanide of potassium, it
is desirable that the plates should be handled only by operators wearing cotton
gloves or hand coverings, as spots of grease or finger marks are liable to show

page_text: imperfections in the finished plate; the plates are now passed into the depositing
bath by being suspended in a rack frame or dipping apparatus made as follows:-
At the four corners of the tank are secured upright standards or supports
of strong angle iron, tied together at the top also with angle iron. At one end
of the tank is provided a rack bar in connection with a pinion and winding
shaft and wheel, which is carried upon a sliding frame guided in the angles
of the supports by friction wheels or runners.
The counter poise of the sliding frame is effected by weight ropes or chains
carried over grooved pullies at the heads of the stationary frame.
The sliding frame consists of bars of brass or copper, of rectangular form, and
from one end of such rectangular frame depend four copper rods (of half inch
round section) six inches apart (for the case which I shall particularize); and these
rods are bent at about twenty two inches from the top at right angles and carried
longitudinally over the tank to the opposite end, and thence bent upward to join
the rectangular frame. Transversely in this sliding frame rods are arranged at
five inch distance at the top, and attached to said transverse rods are hinged
pieces which may be called "butterfly pieces," arranged so as to bear upon the
top edges of the plates to hold same against and upon the longitudinal bottom rods,
so as to hold the plate in vertical position without touching or covering any part
of the faces thereof whilst the deposition is going on. This movable frame with
its charge of plates is raised and lowered into and from position by the rack and
pinion as desired in course of the operation.
The racks may be made to hold any number of plates, but it is preferable that
they should not be made to hold a larger number than, say, 28 (fourth of a "box"
for convenience), as it is found in practice that the time, although short, occupied
in loading the rack with an excessive number of plates, is sufficient to allow of
their becoming oxidized by the action of the air, which should at all times be
avoided. When the rack has been loaded or charged with the plates prepared as
before described, they are lowered into the depositing solution contained in the
tank or vat. This depositing solution I prepare by adding 192 parts (by weight)
pyro-phosphate of soda, and 70 parts of proto-chloride of tin, to five thousand parts
of water which has been previously boiled, and then these substances are added to
the water and stirred until nothing more will dissolve. A slight milky appearance
of the solution will nearly always be apparent, owing to the oxidation of the
chloride of tin by exposure to the air, this oxide should be filtered off, and when
the solution is clear there is to be added 45 parts by weight of cyanide of potassium,
and a few drops to each gallon of solution of a "brightening mixture," herein after
described, the quantity of which must be regulated very cautiously and added
drop by drop per gal of the depositing solution contained in the tank, allowing
some hours to pass between each addition, as too little will not give the desired
deposit of bright tin, whilst too much will make the deposit brittle, somewhat
resembling glass in appearance; but in making up the solution with a careful hand
and testing the character of the deposited tin a few hours after the addition of
the "brightening mixture," the exact quantity to be added will be arrived at, which
will impart to the solution the property of yielding a beautifully bright deposit of
tin when acted upon by a current of electricity of proper tension and quantity.
I make the brightening mixture in the following manner :-Distilled water or
boiled water is saturated with cyanide of potassium; to this I add an equal quantity
of ether, P. B. sp. gr. 0-735; to this I add a quantity of bisulphuret of carbon,
which after a few days will become dissolved by the aforesaid mixture, and any
excess of bisulphuret of carbon will remain at the bottom of the bottle containing
the mixture; this brightening mixture requires or is the better for several days' repose
before being used. I have made a brightening mixture by dissolving bi-sulphuret
of carbon in a saturated solution of cyanide of potassium above, and in a mixture
of a solution of cyanide of potassium and methylated alcohol in varying proportions,
as also in ether alone, and in various proportions of ether and cyanide of potassium,

page_text: but in practice I find the first directions herein set forth for making the brightening
solution give the best result.
I have deposited tin upon prepared black plates from solutions of chloride of tin
and from solutions of pyrophosphate of potash with and without cyanide of
potassium added in widely various proportions, also in solutions of pyro-phosphate
of soda with and without cyanide of potassium added; and in the large majority of
these cases I have found a very great improvement in the brightness of the tin
deposit by the use of the "brightening mixture" herein before named. Whilst
any solution of soda, potash, or cyanide of potassium and protochloride of tin,
having the brightening mixture added in the manner herein before described, may
be used with very good results, I prefer the one particularized. The baths intended
to contain the tin depositing solution should be made of black iron or slate, and of
suitable size to take in the plates intended to be tinned, the most convenient size
will be found to be six feet long, twenty four inches deep, and thirty inches wide,
which will contain twenty eight plates, twenty inches by fourteen, each to be
deposited upon at one time; any smaller size plates can be tinned in same bath as
a matter of convenience.
Lengthwise of the tank along the top of the sides are placed the copper con-
ducting anode and cathode rods (which should not be less than three quarters of an
inch in section) from the dynamo electric machine, the anode rod being connected
at regular distance by transverse rods (five inches apart in this particular case),
from which are hung and depending into the solution by copper books sheets or
cakes of tin metal, which may be roughly cast of any convenient thickness and
have a surface of about twenty one inches by fifteen, and the cathode rod is put in
connection with the plates to be tinned arranged in the rack as before described by
the whole length of the edge of the rack resting thereupon, when said rack is
lowered in such manner as to present a large surface of perfect contact with the
cathode rod.
The dynamo-electric machine preferred to be used in carrying this Invention
into practice is that made according to the Specifications of Letters Patent bearing
date and numbered respectively the 4th September 1879, No. 3565, and
22nd September 1880, No. 3882, granted to the present applicant.
The bath being charged with platea, the dynamo-electric machine is set to work
and the tin will be deposited upon the plates, and according to the strength of
current relatively to the surface exposed, and to the time of subjecting such plates
to the electric action, so will the deposit of tin be more or less, and a resistance
coil is put in circuit to regulate the strength of the current to the surface upon
which it is desired to operate.
I also put in circuit one of the Elmore automatio reverse current preventors,
described in the Specification of Letters Patent, No. 8565, dated 4th September
1879, before referred to.
When sufficient tin has been deposited, the plates are removed from the bath,
rinsed in bot or boiling water, and passed into bot (hardwood) sawdust to dry the
surface, and for most practical purposes these plates are bright and lustrous
enough without further treatment; but to give a fine finish I treat the plates as
and by the means following:-If it is desired only to give the appearance to the
plates of fine frosted silver, they are passed through fine wire scratch brushes; but
for giving a burnished surface I employ a burnishing tool in the machine between
the first and last sets of scratch brushes, or of a set of scratch brushes and final
buffing rolls.
The apparatus for this polishing or finishing purpose consists of a bed plate
mounted upon suitable standards or framing. At the head of the machine are
bearings for carrying and gear for driving a pair of cross shafts to be fitted with
fine wire scratch brushes, and at the opposite end of the machine a second pair of
shafts for scratch brushes with corresponding gearing may be fitted or not according
to the finish to be given to the plates.

page_text: After the first pair of scratch brushes, the plate in its passage through the
machine comes on to the bed plate, which is of polished steel surface, and above
this is arranged in reciprocating slide bearings a burnishing steel bar of rounded
surface form, to which a rapid to and fro motion is imparted across and upon the
surface of the plate under treatment, and strong lye, water, beer, or other emulsive
or softening liquor to facilitate the burnishing action is dropped upon the plate
during progress of the work.
Plates having a deposit of so small a quantity of ten ounces of tin to the "box,"
that is, a box of 112 sheets, 20 x 14, treated by this scratch brushing and burnishing
machine receives a surface and finish of brilliant lustrous and continuous metal,
that is, the action of the burnishing tool upon the deposited surface presses out and
together any infinitesimal pores in the deposited metal of the coating, so as that
the fibre of the metal is perfect in its continuity whilst the lustre is perfect.
Instead of this mode of treatment a fair result can be obtained by passing the
tinned plates through polished steel or chilled iron rollers running at speed in
opposite direction or at differential speeds, also the tinning of the plates may have
a certain finish given to them by subjecting them to surface heat so as just to float
the metal on the plates.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Elmore in the Great Seal Patent Office on the
8th December 1881.
WILLIAM ELMORE, of 91, Blackfriars Road, in the County of Surrey, Electrical
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF TIN-PLATE,' AND IN THE
TINNING AND FINISHING OF SUCH PLATES, OR OF TINNED ARTICLES' AND IN
MACHINERY OR APPARATUS TO BE USED THEREWITH.”
'
"
This Invention relates to improvements in the manufacture of "tin plate" as
such is known in the tin plate trade, that is, the tinning or coating with tin of
the body plates of sheet irop, and in finishing such plates with a lustrous and
polished surface, and in machinery to be employed in such improved manufacture.
The Invention being also applicable for use in tinning or coating with tin other
metallic articles (other than sheets), the object of the Invention being to reduce to-
practice the tinning of the plates or articles by electro-deposition of the metal in
contradistinction to the old process of dipping the plates into cauldrons of molten
metal for tinning the same.
"
In carrying out the Invention I take what are known as black plates which
have been pickled," annealed, cold rolled, and finally pickled preparatorily to
being tinned. These plates having been freed from oxide in the final pickling and
Scouring, and present a chemically clean surface, are now immersed and rinsed in a
tub of clear water, or which may contain a little potash or cyanide of potassium,
it is desirable that the plates should be handled only by operators wearing cotton
gloves or band coverings, as spots of grease or finger marks are liable to show
imperfection in the finished plate. The plates are now passed into the depositing
baths by being suspended in a rack frame or dipping apparatus made as follows:-
This is shown in section in Figs. 1 and 2, and plan, Fig. 3, showing at the four
corners of the tank A upright standards or supports B of strong angle iron, tied
together at the top also with angle iron. At one or both end or ends of the tank
is provided rack bars C in connection with a pinion and winding shaft D, and
winch handle or wheel which is carried upon a sliding frame E guided in the
angles of the supports by friction wheels or runners. The counter poise of the
sliding frame is effected by weight ropes or chains F carried over grooved pullles Fª
at the beads of the standards B of the stationary frame.
The sliding frame F consists of bars of brass or copper of rectangular form, and
from each end of such rectangular frames depend copper rods G (of half inch round or
square section) and these rods are bent at about twenty-two inches from the top at
right angles, and carried longitudinally at G' over the tank to the opposite end, and
thenes bent upward to join the rectangular frame E. Transversely in this sliding
frame E at the top thereof are arranged rods E at five inch distance, and attached
to said transverse rods are hinged pieces H, which may be called "butterfly pieces,"
arranged so as to bear upon the top edges of the plates to be treated to hold same
against and upon the longitudinal bottom rods C, so as to hold the plate in vertical
position without touching or covering any part of the faces thereof whilst the
deposition is going on. The hinged arms of the butterfly pieces H act by their
own weight to retain the plates in position, or may be weighted additionally.
This movable frame E with its charge of plates is raised and lowered into and
from position, as desired in course of the operation.
The movable frame E may be made to hold any number of plates, but it is
preferable that they should not be made to hold a larger number than, say, 28
(one fourth of a "box" for convenience), as it is found in practice that the time,
although short, occupied in loading the rack with an excessive number of plates is

page_text: sufficient to allow of their becoming oxidized by the action of the air which should
at all times be avoided.
When the frame has been loaded or charged with the plates prepared, as before
described, they are lowered into the depositing solution contained in the tank or
vat A. This depositing solution I prepare by adding 192 parts by weight pyro-
phosphate of soda and 70 parts of protochloride of tin to five thousand parts of
water which has been previously boiled, and then these substances are added to
the water and stirred until nothing more will dissolve. A slight milky appearance
of the solution will nearly always be apparent owing to the oxidation of the
chloride of tin by exposure to the air. This oxide should be filtered off, and when
the solution is clear there is to be added 45 parts by weight of cyanide of
potassium, and a few drops to each gallon of solution of a brightening mixture,
hereinafter described, the quantity of which must be regulated very cautiously
and added drop by drop per gal. of the depositing solution contained in the tank,
allowing some hours to pass between each addition, as too little will not give the
desired deposit of bright tin, whilst too much will make the deposit brittle,
somewhat resembling glass in appearance; but in making up the solution with a
careful hand and testing the character of the deposited tin a few hours after the
addition of the "brightening mixture," the exact quantity to be added will be
arrived at which will impart to the solution the property of yielding a beautifully
bright deposit of tin when acted upon by a current of electricity of proper tension
and quantity.
I make the brightening mixture in the following manner: -Distilled water or
boiled water is saturated with cyanide of potassium; to this I add an equal quantity
of ether, P. B. sp. gr. 0-735; to this I add a quantity of bisulphuret of carbon,
which after a few days will become dissolved by the aforesaid mixture, and any
excess of bisulphuret of carbon will remain at the botom of the bottle containing
the mixture; this brightening mixture requires, or is the better for several days'
repose before being used. I have made a brightening mixture by dissolving
bisulphuret of carbon in a saturated solution of cyanide of potassium alone, aud in
a mixture of a solution of cyanide of potassium and methylated alcohol in varying
proportions, as also in ether alone, and in various proportions of ether and
cyanide of potassium, but in practice I find the first directions herein set forth for
making the brightening solution give the best result. I have deposited tin upon
prepared black plates from solutions of chloride of tin and from solutions of pyro-
phosphate of potash with and without cyanide of potassium added in widely
various proportions, also in solutions of pyro-phosphate of potash with and without
cyanide of potassium added, and in the large majority of these cases I have found
a very great improvement in the brightness of the tin deposited by the use of the
brightening mixture" herein before named. Whilst any solution of soda, potash,
or cyanide of potassium and protochloride of tin having the brightening mixture
added in the manner herein before described may be used with very good results,
I prefer the one particularized. The baths intended to contain the tin depositing
solution should be made of black iron or slate, and of suitable size to take in the
plates intended to be tinned, the most convenient size will be found to six feet
long, twenty four inches deep, and 30 inc. wide, which will contain 28 plates,
20 inc. by 14, each to be deposited upon at one time. Any smaller sized plates
can be tinned in same bath as a matter of convenience.
u
Lengthwise of the tank along the top of the sides are placed the copper
conducting anode and cathode rods which should not be less than three quarters of
an inch in section) from the dynamo electric machine; the anode rod will be
connected at regular distances by transverse rods (five inches apart in this particular
case), from which are hung and depending into the solution by copper books sheets
or cakes I of tin metal, which may be roughly cast at any convenient thickness and
have a surface of about 24 in. in depth by four in. wide. The cathode rod is put in
connection with the plates to be tinned, arranged in the frame E before described,
by the whole length of the edge of the frame E resting upon said cathode rod,

page_text: when said frame E is lowered in such manner as to present a large surface of
perfect contact with the cathode rod. The anodes I are to hang upon their rods
and hooks betwen the longtudinal bottom rods G₁ of the frame E, and arranged
so that when the frame with its load of plates to be treated is lowered into the
tank the anodes cannot by any possibility touch the longtudinall bottom rods of
the frame E, which slide up and down between them in order to prevent short
circuit being set up.
The dynamo electric machine preferred to be used in carrying this Invention
into practice is that made according to the Specification of Letters Patent, bearing
date and numbered respectively the 4th September 1879, No. 3565, and
22nd September 1880, No. 3832, granted to the present applicant. The bath being
charged with plates, the dynamo-electric machine is set to work and the tin will be
deposited upon the plates, and according to the strength of current relatively to
the surface exposed and to the time of subjecting such plates to the electric action,
so will the deposit of tin be more or less, and a resistance coil is put in circuit to
regulate the strength of the current to the surface upon which it is desired to
operate.
I also put in circuit one of Elmore's automatic reverse current preventors
described in the Specification of Letters Patent, No. 3565, dated 4th Sept.
1879. When sufficient tin has been deposited the plates are removed from
the bath, rinsed in hot or boiling water, and passed into hot hardwood sawdust
to dry the surface, and for most practical purposes these plates are bright and
lustrous enough without further treatment; but to give a fine finish I treet the
plates as and by the means following:-It is desired only to give the appearance
to the plates of fine frosted silver, they are passed through fine wire scratch brushes;
but for giving a burnished surface I employ a burnishing tool in the machine
between the first and last sets of scratch brushes or of a set of scratch brushes and
final buffing rolls. Apparatus for this polishing or finishing purpose is shown in
longitudinal section, Fig. 5, and plan, Fig. 6, and consists of a bed plate K mounted
upon suitable standards or framing. At the head of the machine are bearings for
carrying and gear for driving a pair of cross shafts to be fitted with fine wire
scratch brushes, with corresponding gearing fitted or not according to the finish
to be given to the plates, not shown in the Drawings.
After the first pair of scratch brushes M the plate in its passage through the
machine comes into the bed plate K, which is of polished steel surface, and above
this is arranged in reciprocating slide bearings N a burnishing steel bar O of rounded
surface form, to which a rapid to and fro motion is imparted across and upon the
surface of the plate under treatment, and strong lye, water, beer, or other emulsive
or softening liquor to facilitate the burnishing action is dropped upon the plate
during progress of the work, as from tank P, see Fig. 5.
Plates having a deposit of so small a quantity as ten ounces of tin to the
"box," that is, a box of 112 sheets 20 x 14, treated by this scratch brushing and
burnishing machine, receives a surface of brilliant, lustrous, and continuous metal,
that is, the action of the burnishing tool upon the deposited surface presses out
and together any infinitisimal pores in the deposited metal of the coating, so as
that the fibre of the metal is perfect in its continuity whilst the lustre is perfect.
Instead of this mode of treatment a fair result can be obtained by passing the
tin plates through polished steel or chilled iron or surfaced rollers running at speed
in opposite direction or at differential speeds, also the tinning of the plates may
have a certain finish giving to them by subjecting them to surface heat, so as just
to float the metal on the plates. For surfacing or finishing in articles of irregular
form known means may be employed.
Having now described the nature and particulars of the said Invention,
I claim,-
First. The process herein specified for the manufacture, tinning, and surfacing of
tin plates, and for tinning metal articles, consisting of the employment of the tin
solutions, the tin anodes, and the electric current, and in combination with the

page_text: cathode holder or dipping frame E of the plating tank, as and for the purpose
herein set forth and described in reference to the accompanying Drawing.
Secondly. The tank and dipping or holding frame E, constructed and operating
for the purpose of the manufacture of tin plates in manner and for the purpose
herein set forth and described in reference to Figs. 1, 2, 3, and 4 of the
Drawings.
Thirdly. The butterfly holder H in combination with the rods G, C, for holding
the plates in the frame E, as and for the purpose set forth and shown by the
Drawing.
Fourthly. The machinery or apparatus for the purpose of finishing or surfacing
the tin plates, consisting of the scratch brushes and burnishing bar O traversing
across bed R, operating together with or without further scratch brush or finishing
rollers, constructed and operating as and for the purpose set forth.
In witness whereof, I, the said William Elmore, have hereunto set my hand
and seal, this Eighth day of December 1881.
YARD