Delta Metal

A yellow malleable alloy; takes a fine polish. Can be cleaned by immersion in dipping acid; does not tarnish in moist air. Can be annealed by bringing to a red heat and cooling in air. Can be soft soldered, silver soldered, and brazed; can be forged at a red heat and is non-magnetic. Used largely in shipbuilding and marine engineering. Can be extruded.

Dutch Metal

A bright yellow very malleable alloy; takes a high polish, and can be cleaned by immersion in dipping acid; turns black by exposure to the atmosphere. Can beannealed by bringing to a red heat and cooling in air. Can be soft soldered, silver soldered, and brazed. Used largely for imitation gilding, either in leaf or powder. Can be easily distinguished from real gold, as it is readily soluble in nitric acid.

German Silver

A white or yellowish-white malleable alloy; takes a high polish. Can be cleaned by immersion in nitric acid and water and then in dipping acid, but tarnishes on exposure to the atmosphere. Can be annealed by bringing to a red heat and. cooling in air. Can be soft-soldered, silver soldered, and brazed. Has a high electrical resistance.

Gilding Metal

A light brown alloy. Used largely for articles that are afterwards gilt. Similar in properties to Dutch metal but not quite so malleable.

Gold

A bright yellow metal extremely malleable; takes a bright polish. and is cleaned by immersion in a dip consisting of 2 parts by weight of hydrochloric acid and 1 part of nitric acid; this is called "aqua regia". Gold is not affected by the atmosphere. Can be annealed by bringing to a red heat and cooling in the air; must not be moved when at a red heat as it is liable to break. Can be soft soldered,and silver or gold soldered.

Gunmetal

A light brown alloy. Generally used in the form of castings; takes a high polish. Can be cleaned by immersion in dipping acid; turns black by exposure to air. Is annealed by bringing to a red heat and cooling in air. May be soft soldered, silver soldered, and brazed. Used largely for engineering purposes. Gilding metal matches this in colour, and can be bought in sheets, rods, etc.

Iridium

A very hard, white, brittle metal, is very rare and difficult to fuse. Used mostly for scientific apparatus, and for objects to withstand very high temperatures. Cannot be crushed.

Iron, Wrought

A greyish-white metal, malleable at all temperatures; takes a good polish. The scale can be removed by immersion in sulphuric acid 1 part, water 15 parts; rusts on exposure to the atmosphere and is eventually destroyed. Is annealed by bringing to a red heat and cooling in water. May be soft soldered, silver soldered, brazed, and welded either by the blacksmith's method or by the oxy-acetylene method; the former is the stronger.

Iron, Cast

A grey metal very brittle and hard. Used only in the form of castings, is really the crude iron used largely for machinery. When cast iron is deprived of some of its carbon, thereby leaving it much softer and less brittle, it is called "malleable cast iron,and in this form it is often used instead of forgings, as it is cheaper.