because the tube tends to cave in on the inside of the bend (2)
or flatten on the outside (3), or both.
Make the bend as follows: Heat a piece
of No. 2 tube about 2 inches from one end in the lamp flame, turn
FIG. 42
A DRINKING TUBE
|
it constantly and move it back and forth endwise to heat a length
of about 2½ inches. When soft, take the tube out of the
flame, and bend the ends upward until the angle is 90°.
If the bend is flat on the inside or
outside, close one end of the tube in the blowpipe flame,
smooth the other end and allow them to cool, then heat the flat
side of the bend in the blowpipe flame and blow it out slightly.
This makes the diameter of the tube at the bend equal to that
of the remainder of the tube. Cut off the closed end, smooth the
edge, and your bend is complete.
Make bends with No. 4 tube.
Experiment 30. To make a drinking tube.
FIG. 43
A SIPHON
|
Many times when there is sickness in the
house, it is convenient to have a glass drinking tube (Fig. 42),
through which the patient can drink without raising his head.
Make such a tube from a piece of No. 4
tubing. The short arm is equal in length to the depth of the
tumbler; the long arm, or mouthpiece, is about 1 inch longer than
this.
Experiment 31. To make a siphon.
Cut off a piece of No. 4 tubing 8 inches
long, make
|
