MAKING A TOY AUTO TRUCK (_Continued_)
MAKING THE HOOD AND RADIATOR—CUTTING THE VENTS—SOLDERING ON THE
FILLER CAP
The hood and radiator may be made from a cocoa tin, a small olive oil or
cooking oil can, provided that the can is shaped as shown in Fig. 58,
which shows the bottom and sides of a cocoa tin.
The can is first cut down to the dotted line _A_. Then the can is cut
at the dotted line _B_. Then some holes are punched in regular rows in
the bottom of the can to produce the radiator. Slits are cut in the side
of the can to form vents and a cap from a tooth-paste or paint tube is
soldered on near the rolled rim for a filler cap and the hood is complete
as shown in Fig. 59.
The rectangular can selected for the hood is marked and cut to shape as
follows: Open the dividers to 2⅝ inches and mark the line _A_ around the
can, Fig. 58. Before cutting the can down to this line set the dividers
to 2¼ inches and mark the line _B_ horizontally around the can. To do
this, rest the can flat on the bench and on the side that is to form
the top of the hood. Rest one point of the dividers on the bench and
let the other point rest against the side of the can where the dotted
line _B_ is indicated. Still holding the can flat on the bench, move it
against the divider point in such a manner that the line _B_ is scribed
horizontally around the sides and bottom of the can.
[Illustration: FIG. 58.]
[Illustration: FIG. 59.]
Cut the can down to the line _A_, then take up a small sharp-cornered
file and file completely through the rolled rim at the corners marked _C_
and _C_ on the line _B_. Use the edge of the file and make a triangular
cut. This filing will greatly simplify cutting the rolled rim which is
hard to cut through with the shears.
Then cut into the rim on the line _B_, cutting from the line _A_. Bend
the two halves of the can open far enough to admit the shears and cut
across the bottom of the can on the dotted line _B_. Cut very carefully
so that the part of the can at the line _B_, forming the bottom of the
hood, will rest flat on the bench all around. If it rests flat on the
bench, it will rest flat on the tin frame of the truck where it is to be
soldered in place.
The next thing to do is to punch the holes to form the radiator. The
front of the hood is rested on a block of wood and a very sharp punch
should be used for punching the holes, such as an ice pick or a very
sharp-pointed nail.
First mark off the radiator in regular squares, using the depressed line
usually found in the bottom of this type of can as a boundary line for
the squares. Divide up the space into squares as indicated in Fig. 60,
_A_, leaving a clear border of tin all around the space to be punched.
Find a block of wood that will fit inside the hood as shown in Fig. 60,
_C_, and place one end of this in the vise. See that the end is sawn off
square before placing the hood over it in the position shown.
Take up the punch and carefully punch the holes as they are marked by the
dots in Fig. 60, _A_, at each line intersection. Then punch a hole in the
center of each square and then a hole should be punched between every
other hole on all the lines forming the squares, see Fig. 60, _B_.
Care should be taken to punch all the holes of the same size and to get
them in regular rows. This makes a neat and workman-like job.
=Cutting the Vents.=—Vents may be cut in each side of the hood with a
sharp chisel. An old wood or carpenter’s chisel about an inch wide will
do very well or a sharp cold chisel may be used.
[Illustration: FIG. 60.]
Use the same wooden block that you used to punch out the radiator on
and place it horizontally in the vise jaws so that enough of it projects
beyond them to support the hood as shown in Fig. 61.
[Illustration: FIG. 61.]
Use the dividers to mark off four or five vents and see to it that they
are laid out square with the hood. Try to find a chisel that is as wide
as the vent is long, a 1-inch cutting edge is about right. Place the edge
of the chisel squarely on the mark and hammer it through the tin with
several blows from the mallet. Make these cuts very straight and parallel
with each other. Cut the vents in both sides of the hood and the hood is
then ready to have the filler cap soldered on.
=Soldering on the Filler Cap.=—Use a large sized screw cap of a
tooth-paste tube or the cap from a paste or paint tube for the filler
cap. Some of these caps are octagonal in shape and have various initials
stamped on the top and these look very much like the filler caps used on
the radiators of real automobiles.
Clean away all paste or paint from the inside of the cap and then
scrape the lower edge bright and clean. These caps are usually made
of a combination of metals that is very much like the solder used for
soldering tin and they will melt very easily if brought in contact with
a soldering copper, so that the cap must be soldered to the hood by an
indirect heating method.
Soldering paste is first applied to the top of the hood where the cap is
to be soldered and then a small puddle of solder is applied to the tin at
this place with a hot soldering copper. The solder is allowed to cool and
then the cap is placed in position on the solder after applying a bit of
soldering paste to its lower edge.
Heat the soldering copper very hot and apply it _inside_ the hood so that
as much of the point as possible rests _directly under the puddle of
solder on which the cap rests_, Fig. 62.
[Illustration: FIG. 62.]
Hold it in this position until the puddle of solder melts and a bright
line of solder is seen to run around the base of the cap where it rests
on the hood. Remove the copper just as soon as the solder melts and runs
around the cap and let the solder harden before moving the hood about.
If the cap moves out of place while the solder is molten, owing to the
bubbling of the soldering paste, it may immediately be pushed back into
place with a matchstick before the solder hardens.
The hood will become very hot before the solder melts under the cap, but
it may be easily held to the bench by wrapping a rag around it to protect
the hand.
A thick square bar of iron may be heated to a dull red at the end and
used in place of the soldering copper for soldering on the cap. Either
the copper or the bar of iron must be very hot. They must be heated to a
much greater temperature than ordinarily used for soldering.
When the filler cap is soldered in place the hood is ready to be soldered
to the frame, but the dash-board and seat should be made before this is
done.