, 1884-09-09
MAKING TIN PLATES.
The Iron Several Times Doubled, Re-
heated and Rolled.
The BLACK Plate" Put In the
"sPiekIe, OF Acid-How the
TIN Coating Il APP
piled.


lScientihc Americana
The following Is the process at the Dyffryn
Tin Plate works. Morristou, near Swansea.
Wales:
In the first place We have what Is termed
bar iron. several feet long, about seven inches
wide, and from one-half to five-eighths OF All
Inch in thickness, rolled according 10 the
plates required at 50 many pounds per foot
1t Is cut in h may be termed Il jack-in the
hox or steam shear, say about nineteen
pounds, b a piece which will eventually 10
rolled into sixteen sheets OF twenty inches
long by fourteen inches vide. III Of such
sheets forming Il box. and weighing when
timed nearly 100 pounds.
This piece Of iron Is dnt placed in a IL
verberatory furnace, heated to redness, put
through the chilled rolls. and rollod in what
is formed thlcks five times; relocated, and
rolled in singles twice. doubled, rehoased,
and rolled three times, doubled, roheated,
ans rolled twice; doubled, reheated, and
rolled Ia cighths twice. until they are stretched
out to tho required length and Thickness
The length OF the bar crceods by about one
inch the width Of tho sheet 10 DO made, ~ a.
TO allow for tho sheaTing process. aud the
bar is therefors rolled with its axis parallel
20 that OF the rolls. Great attention is nee
es.ary in the construction and management
OF the mill furnaces, 20 that the heating Of
tho bar and sheet for rolling may DO
affected with tho utmost regularity, and
without the formation OF ~cale ON tho sur
face or the bars or sheets; for whom scaling
takes place from the draught in the fur
mace being too koen or the heat raised too
high, the quality VI the iron is injured the
scale. II subsequently rolled into the iron.
leaves n rough surface ON the plates in the
after process Of separating and picking.
The plates aro then sheared. and the rough
edges taken of. The iron Of nineteen
pounds or thoreabouts makes sixteen sheets,
which, being cut in halves. leaves eight
sheets in 4 piece closely wedged- Girls with
small iron hatchets opon or separate them.
ThOy ara termed black plate. From one ton Of
bar iron about 1,G75 pounds u black plate Is
made; the loss Is termed ~shearings, and Is
worked up again in the forge fneries The
plates are next sent 10 be picked, l. O., inn
mersed In heated dilute %sulphuric acid, known
as oil OF vitriol.
The plates are placed in n cradleo or rocep-
tacle, lifted by a hydraulic, then dropped
into a round wooden or lead tank containing
the acid: the crndle is then made to rovolvo
by means " steam power. 10 enable the
liquid TO rush between the sheets, which rev
olutiun Is retained. They nra lifted again by
the hydraulic. dropped into IA tub, n little
apart from the last, containing water only,
tho cradle revolving rs ia last tub, 80 that
the water may rush between the sheets to
cleanse or wash away all trace OF the acid
when taken up ngain the plates are clean aud
bright as silver.
The plates are next subjected to a bright
redleat. which lasts from twelve TO twenty
four hours, In closed iron annealing pots in n
roverberatory furnace; they ane well covered
90. -. 49, .. -.~.u a.. B. -. N.G.-
burnt. the heat Is kept ms high as 1t can DO
without softening thom TO such n degree as
10 cause them to stick so fast together ns 10
prevent their separation whom cold
They next pass singly through cold rolls,
three, four, or more times. as may be deemed
requisite. These rolls are highly polished,
and must DO SGT in accurate order TO give tho
plates a perfectly fat sot and well polished
surface. Again they are nnnealed or softened
at a lower temperature than the first, as their
surfaces would be damaged by being in any
degree stuck together. Picked again, as be-
fore, excepting that the liquid is considerably
weaker than previously, placed in c~ast-iron
truughs containing clean water renewed by a
stream constantly flowing through-they are
then taken in hand singly. and secured II nee
essary with sand and hompon pads before be
ing delivered TO the tin-man.
Now comes the last process. The shoets are
iron only so far. They next reach the tim
house, and are placed In a trough containing
clean water, ready for the tinman, as he is
termed, who then picks them up and puts
them singly in a grease pan containing palm
oil, TO soak, and after being there for Il short
timo, the tinmhn places the sheets In n large
iron pot containing molten tin, with a cover
ing OF palm oil. Here II unitos with the tin.
TO which it has II strong affinity when he has
performed his part the plates are handed over
10 the next man, called a washman. whose
pot contains pure molten tin; after they nave
soaked in his pot a little, he raises them with
n tongs on TO the hob ne he 10
quires them, brushes the surfaces Of
both sides OF each sheet. and after dipping
them into another pot containing molten
tin again, they ms sent through rolls which
work In n large pot containing palm oil, and
the speed at which the rolls move regulates
the quantity Of tin TO be put on each sheet
They are afterward raised from the rolls
under which they have been passingl by a
youth called n riser, handed to two young
women who rub them IN bins or boxes con-
tanning bran, one after the other, which
takes of the grease; another girl. called "A
buster, gives them a further polish with q
skin duster, and takes them TO the assorting
room, where every plate passes inspection,
and II not up to the mark Is sent back for
reetiflcation. After passing through that
ordeal, they are counted and weighed and
made up into boxes.