IMPROVEMENTS IN PREPARING CERTAIN METALS APPLICABLE TO THE SHEATHING OF THE BOTTOMS OF SHIPS AND OTHER PURPOSES
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
WILLIAMS, of Pembrey House, near Llanelly, in the County of Carmarthen,
Gentleman, for myself and for THOMAS HAY, of Kidwelly Tin Works, in the
said County of Carmarthen, Gentleman, send greeting.
WHEREAS we did, by Petition, humbly represent unto His most Excellent
Majesty King William the Fourth that we had invented "IMPROVEMENTS IN
PREPARING CERTAIN METALS APPLICABLE TO THE SHEATHING OF THE BOTTOMS OF
SHIPS AND OTHER PURPOSES," which we believed would be of general benefit and
advantage, and that we were the true and first Inventors thereof; and there-
upon His said Majesty, being willing to give encouragement to all arts and
inventions which may be for the public good, is graciously pleased to issue
His Royal Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Seventeenth day of April last, in the fourth year of His
reign; and by those Letters Patent- His said Majesty did, for Himself, His
heirs and successors, give and grant unto us, the said William Williams
and Thomas Hay, our exors, adñiors, and assigns, His especial licence, sole
privilege and authority, that we or they, by ourselves or themselves, or by
our or their deputies, servants or agents, or such others as we or they
should at any time agree with, and no others, from time to time and at
all times during the term of fourteen years from the date of the sealing
of the said Letters Patent, should and lawfully might make, use, exercise,
and vend our said Invention within England, Wales, and the Town of
Berwick-upon-Tweed; and whereas the said Letters Patent also contain a
proviso obliging us, the said William Williams and Thomas Ilay, particularly

page_text: to describe and ascertain the nature of our said Invention, and in what
manner the same is to be performed, by an instrument in writing under
our hands and seals (or the hand and seal of one of us), and to cause the same
to be inrolled in His said Majesty's High Court of Chancery within six
calendar months after the date of the said Letters Patent, as in and by
the same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Williams, for myself and for the said Thomay Hay, do hereby declare
that the nature of our said Invention, and the manner in which the same is
to be performed, is described and ascertained in manner following, that is
to say :-
Our Improvements in Preparing certain Metals applicable to the Sheathing
of the Bottoms of Ships and other Purposes consists in preparing the metal
commonly called zinc or spelter, and the metal called tin, by coating thin flat
plates of laminated zine or spelter with a very thin superficial covering of tin,
which may be effected by a mode of proceedure analogous to that whereby
plates of iron are commonly tinned; and the plates of laminated zinc so pre-
pared by tinning (on one or both sides, as may be thought most suitable), will
be applicable to the sheathing of the bottoms of ships in lieu of the copper
plates hitherto commonly used for that purpose; or such plates of zinc pre-
pared by tinning will be also applicable to the purposes of covering roofs in
lieu of plates of lead or of copper or otherwise for gutters, or for spouts of roofs
for receiving and conducting the rain water therefrom, in any of which applica-
tions the preparation of the zinc by the coating of tin will preserve the zinc
from oxydation by the corrosive effects of sea water upon the sheathing for
the bottoms of ships, or by the effect of tho weather upon roofs and gutters.
And our said improvements in preparing laminated zinc by covering the
same with a superficial coating of tin for the purpose of rendering such
tinned plates of zinc applicable to the purposes of sheathing, roofing, and
guttering, are carried into effect in the following manner:-The plates
of laminated zine which we prepare by our said improvements are now
commonly imported into this country from abroad rolled to various thick-
nesses, and of different dimensions. Formerly such rolled zinc was manu-
factured in England under a Patent which was granted by King George
the Third to Charles Hobson and Charles Sylvester, bearing date the
Twenty-ninth day of April, One thousand eight hundred and five; whereforo
the mode of manufacturing the zinc into thin plates is well known, and,
being no part of our present improvements, does not require to be described
in this Specification. The tin which we use for preparing zinc by our said

page_text: improvements is of the same kind as is commonly used for tinning plates
of iron.
And our improvements in preparing laminated zinc plates by covering them
with tin is performed as follows:--The zinc plates, in the state in which they
come from abroad, have a very smooth and even surface left by the operation
of rolling or laminating. They are first to be slightly pickled in a weak
solution of muriatic acid and water (or sulphuric acid will do, though not
quite so well. The strength of the solution is not very important; but
about one measure of acid diffused in sixteen measures of water will generally
answer the purpose; but the solution may be made as strong as one of acid to
twelve of water, or as weak as one twentieth, and will in either of those
proportions answer the purpose of cleaning the plates by keeping them
immersed a suitable time in the solution, which will be from two to five
minutes, according to the strength of the acid solution, and according to the
state of the plates as to cleanliness of surface when they are immersed therein.
Immediately after the plates of laminated zinc are withdrawn from the acid
pickle they are laid flat upon a work bench, and the surface scoured very
clean by rubbing briskly with a wisp of hemp and coarse sand. This should be
done on both sides of each plate, in order to clean both sides, even although it
may be intended to prepare only one of those sides by tinning; and after being
so scoured, the bright plates of zinc are well washed with water to remove all
the grains of sand or any remnant of the acid solution, and after wiping away
the water the scoured plates are then immersed (either edgeways upwards or
flatways) in a vessel of heated palm oil or hot melted tallow. The vessel is a
rectangular trough or cistern of cast iron or of iron plate, which is set in
brickwork, with a furnace beneath it suitably constructed for burning coals or
coke in order to give heat to the contained oil, and with a sliding damper in
the flue or passage from the fireplace to the chimney suitably for regulating
the draft or current of air through the fire, and consequently the heat, which
beat should be kept very uniform and steady, but at a lower temperature than
that at which pure block tin will melt. The size of the vessel is to be adapted
to that of the zinc plates; and after they have remained in the heated oil or
melted tallow during from two to five minutes they will have become heated,
and the oil or melted tallow will get into very close contact with the recently
scoured surface of the zinc, which is a requisite condition for causing the tin
to adhere firmly. We resort to two different modes of applying the tin to the
said plates of zine which have been thus prepared for receiving the tin, and by
either of those modes the sine may be prepared with tin on both sides, or only
on one side of each plate of zinc, as may be required.

page_text: One of these modes is by dipping the plates of zinc into melted tin in a
manner very similar to the process whereby iron plates are commonly tinned,
and the persons accustomed to the manufacture of tinned iron plates will find
no difficulty in practising that part of our improvements in preparing laminated
zine by tinning the surface thereof by taking the following directions in aid of
their previous knowledge:-The block tin must be of a good quality, and
must be kept melted in a rectangular dipping trough or cistern of cast iron or
iron plate set in brick work, with a furnace beneath it suitably constructed for
burning coals or coke in order to give heat to the cistern and to the contained
tin, and with a sliding damper in the flue or passage from the fireplace to the
chimney suitable for regulating the draft or current of air through the fire,
and consequently the heat, which heat should be kept very uniform at a tempe-
rature which will keep block tin in complete fusion, but not at a much higher.
temperature than that fusion. The surface of the melted tin in the dipping
trough should have as much palm oil or melted tallow floating upon it as will
fill the trough about three inches deep. The depth of the dipping trough must
be sufficient to contain as much melted tin as will permit the plates of zinc to
be wholly immersed therein edgeways upwards, the length of the dipping
trough being adapted to the length of the plates of laminated zinc, which, if
they are intended to be applicable to the sheathing of the bottoms of ships, may
be of the usual size of copper sheathing plates; or, if the plates of laminated
zine are intended to be applicable for roofing or guttering purposes, the plates
may be of any other more convenient size, and the dipping trough, as well as the
trough in which they are previously cleaned and heated in hot palm oil or melted
tallow (as herein-before described), may be made of corresponding dimensions.
The dipping of the plates of laminated zinc into the melted tin is to be per-
formed in the same manner as is commonly practised for tinning plates of
iron, with the precaution to put the zine plate gradually down into the melted
tin with a steady descending motion, and then to draw it up again imme-
diately with a similar motion without allowing it to remain any longer in the
melted tin than is absolutely necessary for the surface of the zine to become
completely covered with a coating of tin firmly adhering thereto, because the
temperature of the melted tin is so near to that at which zinc will melt that
the zinc would become melted if it were left long enough in the melted tin;
and even although the zinc might not become melted if it were dipped and
withdrawn too slowly, nevertheless the tin which adheres to the zinc might
become partially intermelted into and alloyed therewith, in which case the
tinned surface would not be so brilliant in appearance, nor would it be so well
qualified to resist corrosion, as a surface of pure block tin would be, which

page_text: surface of pure block tin may be obtained with very perfect covering over the
zinc surface, and a very firm adhesion thereto, if the previous pickling with
acid and scouring with sand has in the first place rendered the surface of the
zinc perfectly clean and free from all remains of oxydation; and if the washing
with water has completely removed the acid and the sand, and then if the
immersion in hot oil or melted tallow has given the cleaned zinc a proper
temperature, and produced a perfect adherence of the hot oil or melted
tallow to the recently cleaned surface of the sine, all which preparations
being suitably and effectually performed previously to the dipping into the
melted tin, and that melted tin being of a suitable temperature, the time
during which the zine should remain immersed in undergoing the action of
dipping must be proportioned thereto by the discretion of the workman who,
if he has been accustomed to the dipping of iron plates, and is skilful in that
art, he will, after a short time find out how to suit the time of immersion of
the zine in the melted tin to that particular state into which the zinc has been
brought to the treatment which it has previously undergone, so that when the
zine is withdrawn from the melted tin its surface will be completely covered
with a perfectly continuous coating of bright tin of a suitable thickness, neither
thicker nor thinner than is intended to remain thereon, which circumstance
constitutes the principal difference from the usual management of the ordinary
manipulation of dipping iron plates for tinning the same, because these iron
plates are allowed to continue immersed in the melted tin so long as to acquire
a thicker coating of tin than is intended to remain upon the surface of the
iron, and the surplus tin is afterwards removed by immersing the newly tinned
iron plate in hot palm oil or melted tallow contained in a trough, which is
kept heated so hot as to melt tin, and by continuing immersed therein for a
suitable length of time, the surplus thickness of tin is drained off, and collects
at the bottom of the trongh, leaving only such a thickness of tin upon the
surface of the iron plate as it is desired to have; but this mode cannot be
followed in practising our improvement of preparing zinc by tinning the same,
because that metal will not bear a sufficient continuance of the heat of melted
tin to effect such draining off. Note, in dipping the plates of zinc into the
melted tin if they are of large size, such as the usual size of copper sheathing
plates, they will require to be held by two pairs of tongs, one pair applied near
to each end of each sheet, in order to support it steadily without straining or
bending the zinc. In the usual mode of dipping iron plates, one pair of tongs
is found suflicient, because of the smaller size and greater rigidity of the iron
plates; and one pair of tongs will also be sufficient for dipping small-sized
plates of zinc. Immediately after the plate of zinc is withdrawn from the

page_text: melted tin with its coating of tin upon its surface, it is to be immersed in
another trough of hot palm oil or melted tallow exactly similar to that first
mentioned trough in which the plates of zinc were immersed previously to
dipping them in the melted tin, and the temperature of the oil or tallow in
that other trough is kept very near to the temperature of melted tin, being
rather of a higher temperature than the hot oil or melted tallow in which the
zine plates were immersed before they were dipped into the melted tin. The
recently-tinned plate of zinc being left in the heated oil or melted tallow about
one minute or less, the coating of tin will fix itself upon the zinc and retain a
permanently brilliant and even appearance. As soon as the plate of tinned zinc
is finally withdrawn from the last-mentioned trough of hot oil or tallow, it is
laid flat upon a table or bench in order to cool, and its surface is rubbed over
whilst cooling with dry bran applied with a wisp of hemp, in order to remove
all the superfluous oil or grease from the tinned surface first from one side and
then from the other, so as to leave the surfaces perfectly clean and bright, in
which state the plates of zinc so prepared with a coating of tin are ready for
use to be applied in lieu of or in every respect as substitutes for copper plates
for sheathing the bottoms of ships, or for covering roofs or for gutters or
spouts. And in case it should be required to tin the plates of laminated zinc
on one side only, then that side which is not intended to receive the tin should
be brushed over with a thin coating of hot quicklime slacked, and then mixed
with water to the consistency of cream, or else with lamp black and size
mixed to the consistency of thin paint, the coating being in either case spread
on with a painter's brush, so as to cover the whole surface evenly; such a
coating is to be applied to one side of each place of zinc when the same has
been rubbed dry from the water with which it was washed after the scouring
with sand as herein-before described, and so soon as the coating of lime wash or
lamp blank and size is dried upon the surface of the zinc, the same may be
immersed in the hot oil or melted tallow, as herein-before stated, in prepara-
tion for dipping into melted tin, and when that is done the coating of lime
wash or lamp black and size with which one side of the plate of zinc is covered
will effectually repel the tin therefrom, so as to prevent any adhesion of the tin
to that coated side at the same time that the other or bright side of the zine
will become completely tinned, in the manner herein-before explained. And
note, after the dipping of the zine plate, when it is drawn up out of the melted
tin in the dipping trough, covered with tin either on one or on both sides, that
coating of tin may be smoothed and rendered even by drawing a soft hemp
brush along the recently tinned surface, which may be done either in lieu of
immersing the tinned plate of zinc in a second trough of hot oil or melted

page_text: tallow, as herein-before described; or such smoothing with a soft hemp brush
may be used as a preparation to the said second immersion.
The other mode of performing our said improvements in preparing laminated
zinc by coating the same with tin, either on one or on both sides, is as follows:
Immediately after the plate of scoured zinc is withdrawn from its immersion
in a trough of hot palm oil or melted tallow, when, according to the descrip-
tion herein-before given, it would be dipped into the melted tin, instead of so
dipping, it is to be laid flat upon a cast or wrought iron table or plate, which
is heated by means of a fire of coke or of coals made in a fireplace situated
beneath the table, with a sliding damper in the flue leading from the fireplace
to the chimney to enable the heat to be regulated with discretion, so that when
the plate of zinc is laid flat upon the table it shall thereby become heated
sufficiently to melt tin, but very little hotter than that. The said heated table
is nearly of the size of the plate of zinc which is to be laid upon it, with a
shallow gutter extending all round the border or margin of the heated table
to receive the overflow of oil or melted tallow and melted tin, which is
intended to be poured over the upper surface of the zinc plate as it lays
upon the heated table. The melted tin for this purpose is contained in
an iron trough situated at one end of the heated table, having a fire beneath
it similar to the dipping trough before described for dipping, and the
melted tin which it contains is covered over with a suitable depth of
palm oil or melted tallow. The tin is kept melted to a steady heat, and the
operation of applying the tin to the bright surface of the zinc is begun by
taking up a ladleful of the hot palm oil or melted tallow which floats upon
the surface of the melted tin, and which, therefore, has the same temperature
therewith, and pouring out that oil or tallow upon the surface of the zinc, so
as to wash over and bathe that surface therewith, and the oil or tallow, flowing
off on all sides into the gutter which surrounds the heated table, is conducted
thereby back again into the trough from which it was taken up. Another
ladleful of hot oil or tallow is then taken up and poured out over the sinc,
and that mode of washing or bathing the zinc is continued until the zinc
plate is become heated thereby to a proper temperature, and then a ladleful
of the melted tin is taken up out of the trough along with more of the hot
oil and the tin poured out upon the zine. And as the melted tin flows thereon
it is rubbed about with a brush or swab made of hemp, in order to distribute
the tin and cause it to adhere to the surface of the zinc. The surplus tin
which flows off around the border of the zinc is returned to the melting
trough by the gutter around the heated table. The pouring out of the ladles
full of melted tin and the rubbing thereof into the surface of the zinc by the

page_text: hemp brush is continued until the whole surface is perfectly covered or tinned
on one side, and then the zinc is to be turned over, in order that the other
side may
be treated in exactly the same manner, after which the tinning on
both sides is laid smooth by drawing the newly tinned plate horizontally end-
ways between two soft hemp brushes, one applied to the upper and the other
to the under surface, so as to act upon both sides at once, and render the
surfaces of the tinning very even and smooth. In order to perform the
brushing at both sides at once, a wooden plank or flat table, of the same width
as the plate of zinc which is to be tinned, is to be placed at one end of the
heated table in continuation of the length thereof. One of the hemp brushes
is fixed across the end of that plank, so as to rise up above its surface. And
as soon as the tinning of the plate of zine is finished, that plate is taken in
tongs by one of its ends, and lifted up off the heated table and lifted over
the hemp brush which is fixed across the end of the wooden table, so as to
rest on that brush with its weight, and whilst so resting the plate is drawn
horizontally endways over the brush with its lowermost tinned surface in
contact therewith, at the same time that another similar brush is held firm
by a man across the uppermost tinned surface and in contact therewith, so
that the motion wherewith the plate is drawn endways will cause both the
tinned surfaces to be brushed and laid smooth. And when all the length of
the plate has been drawn endways over the fixed brush, the plate will fall
flat upon the wooden table, and is left there in order to cool; and after the
tin is become fixed and whilst it is cooling it is removed into a trough of dry
bran, where its surface is rubbed with dry bran, first on side and then on the
other, in order to remove the grease and render both the tinned surfaces
perfectly clean and bright. If the tinning is required to be only on one
side of the plate of zinc, the other side thereof may be covered with a
coating of thin lime wash or of lamp black and size, and that side being
laid downwards no tin can attach thereto, then the plate is applied upon
hte heated table, and only the uppermost side is to be turned by the process
above described. And note, fine powdered resin may be dusted over the
bright surface of the plate of zinc when it is laid upon the heated table, and
after it has become properly heated by bathing it by pouring out ladles full of
hot oil or melted tallow in preparation for receiving the melted tin. The
resin being applied upon the surface of the zinc immediately before the tin is
poured on will facilitate the adhesion of the tin to the zinc, but it is not
necessary to use resin. And note, after the plate of zine has been tinned upen
the heated table by the above process of pouring melted tin on it and spreading
with a hemp brush, the recently-tinned plate may be immersed in a trough of

page_text: heated oil or melted tallow in order that the coating of tin may fix itself upon
the zinc in the manner herein-before described for the treatment which is to
follow after the tinning by dipping into a trough of melted tin.
Having now described the nature of our said improvements, I, the said
William Williams, for myself and for the said Thomas Hay, do hereby declare
that the new Invention whereof the exclusive use is granted to us by the said
Letters Patent, consists in the improvements herein-before described in pre-
paring zinc and tin so as to cover the surface of laminated zine on one or both
sides with a complete coating of tin in order to render such tinned zinc
applicable to the sheathing of the bottoms of ships, and to the covering of
roofs, and to the making of gutters and spouts for roofs.
In witness whereof, I, the said William Williams, for myself and for the
said Thomas Hay, have hereunto set my hand and seal, this Seven-
teenth day of October, in the year of our Lord One thousand eight
hundred and thirty-four.
in the year of our Lord 1834, the aforesaid William Williams came before
our said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Inrolled the Seventeenth day of October, in the year of our Lord One
thousand eight hundred and thirty-four.