Experimental glass blowing for boys

by Carleton John Lynde

Experiment 2. To cut glass tubing.

FIG. 7
BREAKING THE TUBE

Cut off a six-inch length of No. 2 as follows: Lay the tube flat on the table, mark the six-inch length and draw the file across the tube at this point, pressing hard enough to make a good scratch (Fig. 6). Grasp the tube with both hands near the scratch, as in Fig. 7, pull apart and bend slightly. Do you find that the tube breaks across easily?

Repeat this with No. 4 and No. 6 tubes.