Tinplate - The Process
Tinplate is a thinly rolled sheet of iron or steel coated with tin. Tin resists corrosion, which makes tinplate suitable for containers of food and drink, tobacco, cooking utensils and many other uses.
Bars of wrought iron or steel were cut to the required size in the cutting shed. These cut lengths were taken to the Hot Rolling mill for rolling to reduce the bars too wafer thickness. |
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The bars were heated to 'blood-red' in the furnace. The FURNACEMAN then took a pair of them out with tongs and dipped them into a bosh(tank) of water. |
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The ROLLERMAN seized one bar with tongs and inserted it between the rolls, which were continually turning, powered by steam. |
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The man on the other size of the rolls, the BEHINDER, caught the bar with his tongs and passed it over the top, back to the rollerman, who meantime inserted the second bar into the rolls. |
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The bar, after repeated rolling and furnace heating had now become an eight-fold pack, with the help of the DOUBLER, whose job it was to fold over the plates and squeeze the folds in the squeezer. The pack was trimmed and cut into the black-plates in the shears. |
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The SHEARER trimmed and cut the pack to the size of the customer's order, using the shears. First and second HELPERS completed the team. |
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The eight blackplates in the pack were separated by OPENERS. From the Hot Rolling Mill the blackplates went to various other processes to prepare them for tinning. |
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In the pickling section the blackplates were loaded into cradles, plunged into two tanks, the first of dilute hot sulphuric acid to dissolve the scale on the plates, the second of water to wash off the acid. |
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To counteract the hardening of the metal during the hot-rolling process, the ANNEALER stacked plates on a cast iron stand and placed a cast iron pot over them. The them charged them into the furnace so that with heating the metal became 'workable'. |
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In the Cold Rolls the plates were rolled without heating to correct the unevenness and burnish the surface. The hardened plates were returned to the annealing house and then to the pickling section. |
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The plates were stored in a lightly acid water to prevent rusting. The TINMAN fed the plates into the tinpot which contained molten tin. They were then cleaned and polished. |
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The plates were sorted and graded. Any plate which had been touched or soiled by accident was rejected, along with any other faulty plates. The plates were then packed in boxes to be dispatched to the customer. |
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