The question that naturally comes up is, can the ordinary battery man
make good lead castings? We will answer “Yes,” very emphatically. There
is nothing mysterious about the work and all the talk of alloys,
compounds and formulae does not mean a great deal.
Pure lead is not hard or rigid enough to make good battery parts,
therefore, it is necessary to add some other metal that will provide the
strength, not be affected by the acid and not increase the resistance
electrically. Antimony has all the necessary qualities, and is,
therefore, commonly used by mixing it with the pure lead.
[Illustration: Figure 4]
The various manufacturers recommend from 2 to 12 percent antimony, as
the proper combination, but in buying new pig lead for castings, a 4
percent antimony compound is very satisfactory.
In using old battery lead, however, due to chemical action the
proportion of antimony is apt to be too high to produce perfect
castings. This usually shows up by cracks or shrinkage, as in Figure 4.
To overcome this trouble, pure lead is added, until a perfect casting is
made. Pure lead can be purchased (in the form of bars, lead pipe, or
sheet lead) from a manufacturer such as the National Lead Company—your
accessory jobber, the local plumber, or the junk dealer. When buying
from a junk dealer, however, care =must= be taken that there is no
solder or tin present.