rning outfit]

8. Carbon Arc. This is a very simple method, and requires only a spare
6 volt battery, a 1/4 inch carbon rod, carbon holder, cable, and clamp
for attaching to battery. This outfit is shown in Fig. 80. It may be
bought from the American Bureau of Engineering, Inc., Chicago, Ill.
This outfit is intended to be used only when gas is not available, and
not where considerable burning is to be done.

In using this outfit, one terminal of an extra 6 volt battery is
connected by a piece of cable with the connectors to be burned. The
contact between cable and connector should be clean and tight. The
cable which is attached to the carbon rod is then connected to the
other terminal of the extra battery, if the battery is not fully
charged, or to the connector on the next cell if the battery is fully
charged. The number of cells used should be such that the carbon is
heated to at least a bright cherry red color when it is touching the
joint which is to be burned together.

Sharpen the carbon to a pencil point, and adjust its position so that
it projects from the holder about one inch. Occasionally plunge the
holder and hot carbon in a pail of water to prevent carbon from
overheating. After a short time, a scale will form on the surface of
the carbon, and this should be scraped off with a knife or file.

In burning in a connector, first melt the lead of the post and
connector before adding the burning lead. Keep the carbon point moving
over all parts to be joined, in order to insure a perfectly welded
joint.

9. Illuminating Gas and Compressed Air. This is the slowest method of
any. Pump equipment is required, and this method should not be used
unless none of the other methods is available.

The selection of the burning apparatus will depend upon individual
conditions as well as prices, and the apparatus selected should be one
as near the beginning of the foregoing list as possible. Directions
for the manipulation of the apparatus are given by the manufacturers.

The most convenient arrangement for the lead burning outfit is to run
pipes from one end of the work bench to the other, just below the
center shelf. Then set the gas tanks at one end of the bench and
connect them to the pipes. At convenient intervals have outlets for
attaching the hoses leading to the torch.

EQUIPMENT FOR HANDLING SEALING COMPOUND

(a) Stove. Where city gas is available, a two or three burner gas
stove or hot-plate should be u