It is necessary when soldering or wiping a joint to cover the parts of pipe adjoining the portion that is to be soldered or wiped so that the solder will not stick to it. There are a number of preparations for this. The one used by the best mechanics today is paste, made as follows:

  • 8 teaspoons of flour.
  • 1 teaspoon of salt.
  • 1 teaspoon of sugar.
  • Mix with water and boil down to a thick paste.

The advantages of paste as a soil are many:

  1. First, it is made of materials easily obtained.
  2. Second, solder will not stick to it.
  3. Third, if pipe is thoroughly cleaned, the paste will not rub off easily.
  4. Fourth, poor workmanship cannot be covered up.
  5. Fifth, when the work is completed, a wet cloth will wipe it off and leave the work clean.

Another soil used is lampblack and glue. A quantity of glue is melted and then lampblack is added. This needs to be heated and water added each time it is used. This soil is put on pipes with a short stubby brush. The work when completed with the silvery joint and jet black borders appears to the uninitiated very artistic and neat, but when the black soil is worn away the uneven edges of the joint appear, disclosing the reason for using a black soil that covers all defects. The mechanic of today who takes pride in his ability for good workmanship will not cover his work with black soil.

It can readily be seen that the use of lampblack soil encourages poor workmanship, while the use of paste forces, to a certain extent, good workmanship on the part of the mechanic.

Before soil or paste is applied, the pipe needs to be cleansed. Grease and dirt accumulate on the pipe. The methods employed to remove all foreign matter are simply to scrape the surface with fine sand or emery paper; sand and water will also answer for this purpose. This cleans the surface and allows the soil or paste to stick to the pipe.