Mixtures of Solders for Soldering Iron and Wiping.
Care of Solders. Melting Points of
Metals and Alloys
The importance of good solder, that is, solder correctly mixed and thoroughly cleaned, should not be overlooked. Work is more quickly and neatly done and the job presents a more finished appearance when solder that is correctly made is used.
The solder used in the following work with the soldering iron is called 1⁄2 and 1⁄2. This means 1⁄2 (50 per cent.) lead and 1⁄2 (50 per cent.) tin.
In the mixture of solder, only pure metals should be used. The lead should be melted first and all the dross cleaned off. The tin should then be added and mixed.
The solder to be used in wiping the joints in the following chapter is a mixture of 37 per cent. tin and 63 per cent. lead. This is called wiping solder.
The following table gives the melting points, etc.:
| Metal | Melting point | Mixture |
|---|---|---|
| Sulphur............. | 228 | Pure |
| Tin.................... | 446 | Pure |
| Lead................. | 626 | Pure |
| Zinc.................. | 680 | Pure |
| Fine solder........ | 400 | 50 per cent. tin, 50 per cent. lead (wt.) |
| Wiping solder.... | 370 | 37 per cent. tin, 63 per cent. lead (wt.) |
To recognize fine solder, run off a bar into a mold and let it cool. If there is a frosted streak in the center, the metal has not enough tin. The surface should be bright. To recognize wiping solder, pour some on a brick. When this is cool, the top should be frosty and the under side should have four or five bright spots. The amount poured on the brick should be about the size of a half dollar. If poured on iron, the metal will cool too quickly and show bright all over the under side.
To Make 1⁄2 and 1⁄2 Solder or Plumber's Fine Solder.—The possibility of getting pure clean metals to mix solder is very remote. Old pieces of lead pipe, lead trap, old block tin pipe are used to make solder when pure metals are not at hand.
- First, in a cast-iron pot melt the lead to about 800°, or a dull red.
- Second, clean off the dross.
- Third, add (to a 15-pound pot) 1⁄2 pound of sulphur in three applications. Each time mix the sulphur thoroughly with the metal with a long stick.
- Fourth, add tin before the last application of sulphur. Mix thoroughly.
- Fifth, pour off two bars and look for the frosty streak in the center. Add a little more tin, if necessary.