The Chemistry of Powder and Explosives - Sciencemadness Dot Org

102 PYROTECHNICS
bundle of stiff 2-inch pieces of black match is inserted into this
space and is held in position by a rolled wrapper of paper, glued
to the fuse case and tied with a string near the ends of the
match, in order that it may not be dislodged by the shock of
setback. The match serves to bring the fire more satisfactorily
to the bursting charge within the shell.
The preparation of the bombshell is hand work which requires
much skill and deserves a fairly full description. We describe the
construction of a 4-inch shell to produce a single burst of stars.
A strip of bogus or news board paper is cut to the desired length
and is rolled tightly on a form without paste. When it is nearly
all rolled, a strip of medium-weight kraft paper, 4 inches wider
than the other strip, is rolled in and is rolled around the tube
several times and is pasted to hold it in position. Three circular
discs of pasteboard of the same diameter as the bogus tube (3y2
inches) are taken, and a %-inch hole is punched in the center
of two of them. The fuse is inserted through the hole in one of
them and glued heavily on the inside. When this is thoroughly
dry, the disc is glued to one end of the bogus tube, the matched
end of the fuse being outside; the outer wrapper of kraft paper
is folded over carefully onto the disc, glued, and rubbed down
smoothly; and the second perforated disc is placed on top of it.
The shell case is now turned over, there being a hole in the
bench to receive the fuse, and it is filled with as many stars
(^-inch diameter, V2 inch long) as it will contain. A mixture of
2F gunpowder and candle comp is then added, shaken in, and
settled among the stars until the case is absolutely full. A disc
of pasteboard is placed over the stars and powder, pressed down
against the end of the bogus body and glued, and the outer
kraft paper wrapper is folded and glued over the end.
At this point the shell is allowed to dry thoroughly before it
is wound with strong jute twine. It is first wound lengthwise;
the twine is wrapped as tightly as possible and as firmly against
the fuse as may be; each time that it passes the fuse the plane
of the winding is advanced by about 10° until 36 turns have
been laid on, and then 36 turns are wound around the sides of
the cylinder at right angles to the first winding. The shell is now
ready to be "pasted in." For this purpose, 50-pound kraft paper
is cut into strips of the desired dimensions, the length of the
strips being across the grain of the paper. A strip of this paper