In the ordinary strip-work nothing is used to connect the bands except riveting and clamps. But to unite portions of frames there must often be if not positive welding at least an union of metal to metal by means of soldering or "soddering," which is a kind of welding, as it joins iron by heating and using a flux or another substance which serves to soften it.

Soldering can be learned by any boy with great ease from any smith, or even from the first tinker - the latter class having probably by far the most pupils, as there are few village boys who have not watched them at work. And as it is to the last degree improbable that any of the readers of this book will live where they cannot see soldering, - for I have heard of a gypsy tinker being found at work in a remote place by the Great Wall of China, - I might dismiss this subject by advising them to go to the nearest worker in metal of any kind.

Solder (Latin solidare, to make solid), is a compound of extremely fusible metal, yet which sets hard, and which, used in connection with certain other substances, as for instance the spirits of salts and zinc or resin, will, with a very moderate heat, at once unite iron with iron. There are different kinds of solder for different metals, as, for instance, silver solder. Spelter is another combination of metals, in different proportions, used for the same purpose but in a different way. For ordinary soldering, file the parts to be united quite clean, sprinkle them with powdered resin, and put on this a small piece or pieces of solder. Having a spirit lamp at hand, turn the blaze on the resin, which will burn and melt the solder, which will unite the iron.

For larger work use spirits of salts to rub the surface, and melt the solder with a hot iron or on a brazier. The spirits of salts here serves to draw or flux the solder. Where broad surfaces are thus treated and are brought together by clamping or pressure, the process is known as binding or sweating on.

Brazing is another variety of the same work. It requires greater heat, that is, a fire generally with bellows, or a blow-pipe. For this spelter is employed, being first powdered. This is mixed with borax and water, and passed between the portions which are to be united. When the heat is sufficiently high the spelter and borax will fuse and unite the iron. This is rougher work than the former, and is such as is generally practised by smiths.