The process of tinning sheets follows very much the same lines as galvanising, the molten metal in this case being tin, and the flux generally a solution of chloride of zinc. The plates are run through several pairs of rolls, and ultimately up out through a "grease-pot" filled with palm oil.
Tinplate is of no use for outside purposes on account of the readiness with which it rusts. This is probably due to the fact that iron and tin have very little affinity to each other, causing the surface of the iron to be imperfectly coated. The miscroscopic points on the sheet left uncoated quickly rust when placed in a damp atmosphere, this being, no doubt, assisted by some electric action.
Tin and copper have a very much greater liking for each other than tin and iron; therefore copper can be more readily and firmly tinned than iron. Its surface should be well cleaned, and then sprinkled with salammoniac, small pieces of tin placed on it, heated, and run over the surface, and finally wiped off with a wisp of tow. Any greasy parts on black iron or other metal that has to be tinned or galvanised, should first be either burned off or removed by a solution of soda. In tinning copper, if there are any parts that require to be left untinned, these should be first brushed over with whitening paste.
Tinned copper vessels make excellent cooking utensils where a quick heat is required, on account of the good conducting power for heat of copper, and also the cleanliness of a properly tinned copper vessel. Tin is not easily dissolved by vegetable or meat juices; but as copper quickly forms a poisonous verdigris, care should be taken to see that saucepans, etc., are kept properly tinned.