This section is from the book "Soldering For Workshop, Farm And Home", by John Bonert. Also available from Amazon: Soldering For Workshop, Farm And Home - Information On Soft And Hard Soldering - Projects For The Workshop Explained And Illustrated.
Copper is about the most useful of all metals. Without copper our communication systems and electric supply systems would hardly be possible in their present proficiency. It is one of the best conductors of electricity and a very good conductor of heat. It is used for too many purposes to mention at this time. It is used in many alloys. Our silver coins contain about 10% copper. The different grades of bronze including bell-metal contain some copper. It is used in brass, German silver, and in many hard solders used for brazing. It tins very easily.
Brass is a composition of copper and zinc. There are many uses for it such as plumber's fittings and pipes, fittings for boats and ships, wood and machine screws, hardware for building, electrical devices and for many more articles where a non-corrosive metal is required. Brass comes in different qualities depending on the composition. With only a little zinc it is almost red and becomes lighter in color with the addition of more zinc. The higher quality of brass depends on the greater amount of copper used in its composition. Some brass is sold under the name of bronze but genuine bronze is a composition of copper and tin. Brass tins easily but must not be overheated. There is no danger of overheating it with a soldering copper, but when it is heated by a flame the zinc in the composition can be burned by overheating and this will spoil the tinning.
Bronze is an alloy of copper and tin. For different purposes the amount of tin varies. It is used for making bells, for expensive ornamental hardware and fittings, fixtures and partitions such as are used in offices and banks where artistic metal doors and door frames are needed. It is an easy metal to solder.
Galvanized iron is ordinary iron or steel coated with zinc just as some other metals are coated with tin. The iron is cleaned and fluxed and then dipped into a bath of hot zinc. The quality of the product depends on this coating. Some articles are made after the iron or steel is galvanized such as cans, pails, wire fencing and many others. This is a very bad practice because in bending and seaming the metal, the coating of zinc may be loosened or cracked. This means that rust will begin action at these points. When buying articles made of galvanized iron always be sure they have been galvanized after bending or in the case of fencing, after weaving. This can be detected by examining the seams and twists to see if the zinc has filled all such places. For work where the cost of brass would be prohibitive especially in plumbing, galvanized iron is usually used. Galvanized fencing has been known to last as long as fifteen years exposed to the elements before any rust appeared. One of the easiest metals to tin.