Tin

A white metal, with a yellowish tinge, very malleable; takes a good polish. Can be cleaned by immersion in hydrochloric acid and water. With care it may be soft soldered. It is little affected by air at ordinary temperatures, and is therefore used largely for coating sheet iron to protect it from rust, as in culinary vessels.

Tin Plate

This is small thin sheets of wrought iron or mild steel, which have been annealed, pickled, scoured bright, and dipped in molten tin on the top of which there is a quantity of melted tallow so that the sheets of metal pass through the melted tallow before entering the molten tin. The tallow is a flux and causes the tin to adhere to the metal sheets. The metal is then passed through rollers which squeeze off the excess tin, and they are then dried in clean sawdust.

Block tin, as it is called, or doubles, are iron or steel sheets that have been dipped twice, so having a thicker coat of tin on them, then planished with a polished hammer on a polished anvil. They are usually from 20-25 I.S.W.G.

Terne plates, which are duller in appearance than tinned plates, are plates dipped in a mixture of lead and tin.

The commercial names of tinned plates are very confusing, and the sizes vary. They are named by the size of the sheet, the quality, and thickness. For example, Common No. 1 is marked I.C. and the size is 14 x 10 in., and there are 225 sheets in a box weighing 108 lb.; the thickness is No. 30 I.S.W.G. Another DXXXX, called four cross doubles, is No. 22 I.S.W.G.; size of sheet is 17 x 12 1/2 in., or 17 x 25 in.

Tool Steel

A greyish white metal, malleable, very strong and tough; takes a high polish. Can be cleaned by immersion in a mixture of nitric acid and lamp black. Oxidizes on exposure to the atmosphere. Is annealed by heating slowly to a dull red and cooling in hot sand or lime very gradually. May be soft soldered, silver soldered, and brazed. With care can be welded. Sometimes called crucible steel, cast steel, carbon tool steel.

Tungsten

A grey metal, very rare, very hard. Used for alloying with steel to produce what are known as self-hardening steels.

Tungsten Steel

A very hard steel. Used for cutting tools in engineering shops. Can be forged at a red heat and is hardened by bringing cutting edges to a white melting heat and cooling in a cold blast of air. Cutting edges last much longer and do more work than carbon tool steels.

Type Metal

A grey metal, fairly soft. Used only for casting type for printing; expands on solidifying.

Zinc

Sometimes called spelter. A bluish metal, fairly malleable at certain temperatures; takes a fair polish. May be cleaned by immersion in equal parts of nitric and sulphuric acids. Is annealed by warming with a bunsen burner, and can be soft soldered. Used largely for alloying with other metals and for the protection of iron from rust as in galvanizing.