Tinplate consists of sheets of steel coated with a thin layer of tin to impede rusting.
Before the advent of cheap mild steel, the backing metal (known as "backplate") was wrought iron.
Formerly, tinplate was used for tin ceiling, and holloware (cheap pots and pans), also known as tinware.
For many purposes, tinplate has been replaced by galvanised metal, the base being treated with a zinc coating.
It is suitable in many applications where tinplate was formerly used, although not for cooking vessels, or in other high temperature situations—when heated, fumes from zinc oxide are given off; exposure to such gases can produce toxicity syndromes such as metal fume fever.
Tinplate was apparently produced in the 1620s at a mill of (or under the patronage of) the Earl of Southampton, but it is not clear how long this continued.
In doing so, they were sponsored by various local ironmasters and people connected with the project to make the river Stour navigable.
In Saxony, the plates were forged, but when they conducted experiments on their return to England, they tried rolling the iron.
It is likely that the intention was to roll the plates and then finish them under a hammer, but the plan was frustrated by William Chamberlaine renewing a patent granted to him and Dud Dudley in 1662.
Another Thomas Cooke, perhaps his son, moved to Pontypool and worked there for John Hanbury.
This caused a great retrenchment in the British industry and the emigration to America of many of those were no longer employed in the surviving tinplate works.
In the pickling department, the plates were immersed in baths of acid (to remove scale, i.e., oxide), then in water (washing them).
They were then washed and stored in slightly acid water (where they would not rust) awaiting tinning.
This is followed by the grease pot (containing an oil), removing the excess tin.
This provided a continuous process, eliminating the need to pass the plates over the rolls and to double them.