Practicing the Blowing.
Now, for practice, take two pieces of ¼-inch lead tubing and prepare them as for a cup joint, by spreading one end with the bending iron and rasping the other end to fit the cup, as shown in a, Fig. 33. Support them as you best can in an upright position. Flux the joint with rosin. Then take the solder in the left hand, set the lighted candle at the right hight and distance from the joint, as shown at B, Fig. 47, which leaves the right hand free to manage the blow pipe. Then heat the joint with the flame, and, as it gets hot, touch the joint with the solder, and when it reaches the melting temperature of the solder a drop of it will detach itself and flow clear around the joint, making a smooth, clean joint that is stronger than the pipe itself.
Joints made in this manner present a handsome and workmanlike appearance to the mechanical eye. Practice diligently on the lead pipe until you have become so proficient that you can flow the solder all through the joint without withdrawing the flame. Then procure some ⅜-inch block tin pipe, and, when that can be soldered perfectly, the beginner can consider himself sufficiently proficient to practice on flat seams on Britannia metal.