—First make a hole in the side of the tube in the manner already described and then cork up both ends; heat the tube around the hole and one end of the other tube as shown at [B, in Fig. 91]. When they are soft press them together hard enough to make a good joint.
It is a good scheme to wrap cotton around the joint while it is still hot to anneal the glass, which means to make it less brittle by letting it get cold slowly.
Fig. 92b. cross section of a home made blow-pipe
To Blow a Bulb on the End of a Tube.
—How to Make a Blow-Pipe.
—For blowing bulbs on tubes, for flasks and the like, you need a regular glassblower’s blow-pipe in order to get a hotter flame than a Bunsen burner gives.
You can buy a blow-pipe as shown at [A in Fig. 92] for $1.50,[101] or you can easily make one as follows: get a brass tube ³⁄₄ inch in diameter and 10 inches long and drill a ¹⁄₂ inch hole in it 3 inches from one end; fit another pipe of the same size and length at an angle of about 30 degrees to the first one; put a stopcock in the latter pipe and solder it to the first pipe over the hole as shown at [B in Fig. 92].
[101] Blowpipes and bellows can be bought of Hammacher, Schlemmer and Co., Fourth Ave. and 13th St., New York.
Next take a glass tube ¹⁄₄ inch in diameter and 14 inches long and make a bend in it 3 inches from one end. Make a hole through a cork and push it over the glass tube; slip the tube into the brass pipe and force the cork into the end of the latter tight enough to hold the glass tube exactly in the middle of it.