Uses

Tin is used in building for lining lead pipes, occasionally as a protective covering for iron plates, and for small gas tubing.

Ores

The metal is obtained from an ore called "tin-stone" - the bin-oxide, and also from tin pyrites. The ore is stamped; roasted to expel sulphur and arsenic; washed, mixed with flux, and smelted in a reverberatory furnace, whence the liquid metal is run into a basin, and thence into moulds. The ingots thus produced are refined and boiled.

Properties

Tin is very soft, more easily fused than any other metal, very malleable, and very slowly oxidised, but its tensile strength and ductility are very low.

Tin may be distinguished from other metals by its crackling when bent. Its purity is tested by its extreme brittleness at high temperatures.

Tin Tubing is made of diameters varying from 1/4 to 1 inch, and of light section, for the conveyance of gas, but is now not much used, having been superseded by the composition tubing described below. The cost of the metal makes it too expensive, if made strong enough, for water supply.

Composition Tubing is made from a mixture of tin, lead, and antimony. It is extensively used for the smaller branches of gas supply, being much less expensive than tin tubing, is easily bent to suit any position, and can be attached to connections by soldering.

1 Bloxam.

Weight In Ounces Per Yard Run Of Tin And Of Composition Tubing

Internal Diameter.

Weight per Yard in ounces.

Tin.

Composition.

1/8

. . .

5

3/16

..

8

1/4

7 to 8

11 to 13

5/16

9 to 91/2

14 to 16

3/8

11

18 to 21

7/16

14

23 to 26

Internal Diameter.

Weight per Yard in ounces.

Tin.

Composition.

1/2

17

29 to 34

9/16

...

36

5/8

23

44 to 52

3/4

30

52 to 68

7/8

38

64 to 76

1

47 to 48

80 to 88

Tin Plate is iron plate covered with a coating of tin by a process similar to that of galvanising, described at page 335, molten tin being used instead of zinc.

Sucb plates are durable until once a hole is made in the covering, after which galvanic action sets up between the tin and iron, and the former is rapidly eaten away.

There are two kinds of tin plate, charcoal plate and coke plate, so called from the plate iron being made with charcoal and coke respectively.

Terne Plate is described at page 287.

Block Tin or Doubles consists of tin plate with a much thicker coating of tin upon it. It is used for the best tin ware.

Crystallised Tin Plate is made by heating the surface of ordinary tin plate with hydrochloric and nitric acids, which gives it a variegated appearance. This is sometimes known as Moire metallinue.

Tinned Copper is often used for kitchen utensils. The surface of the copper is cleaned before tinning with sal-ammoniac.