to 2000° F. The higher the solder melts, the stronger
the joint it produces will be, and vice versa. For model
boiler work, a solder with a comparatively high melting
point should be used. There are other cases where a
mixture with a low melting point can be used to advan-
tage. One thing must be kept in mind, however, and
this is the necessity of using a solder that is not too close





Fig. 52 — The end of a boiler wired in place ready for silver soldering



to the melting point of the metals that it is to be used
upon. A good solder to use in connection with copper
consists of two parts silver to one part of brass in the
form of brazing spelter. A good mixture for work with
brass consists of seven parts of silver to two parts of
brazing spelter. Silver solder in sheet form can gen-
erally be purchased from large jewelers^ supply houses.
The mechanic can melt up his own ingredients and roll
it out into a sheet if he desires. This is the most suitable



80 Model Engineering

form to use it in, as it does not require such a great length
of time to melt.
