To light the heater, close the air inlet tightly, turn the gas on full and apply a lighted match to the burner. A yellow flame will result. Now open the air vent slowly, by pushing the slide forward a little way. The flame will change from yellow to blue and purple as air is admitted. When the flame is blue, it is giving out the most heat and is in the best condition to heat the copper.
If the flame fires back and lights the gas at the brass nozzle over the air inlet, the gas should be turned off until the flame disappears. The air inlet is then closed, and the gas turned on and lighted, and then the air inlet is slowly opened until the flame turns blue. When the furnace is in use, it should be looked at occasionally to see that the flame has not fired back to the nozzle. Once satisfactorily lighted, the heater may be turned up or down as needed. If the flame is turned down very low the air inlet may have to be closed a bit to prevent the flame from firing back. The copper is placed on the rest provided for it over the flame. After the copper is heated to the flowing point of solder, the flame may be turned down or the copper placed to one side of the flame, so that it does not get too hot.
Charcoal and Wood Fires.—When using a charcoal or a wood fire, the copper should be placed at the bottom among the embers. Small charcoal furnaces used for heating soldering coppers may be bought from the dealer in plumbers’ supplies. Charcoal should not be burned in a closed room as the fumes are deadly unless allowed plenty of constantly changing air. These furnaces may be connected with a chimney or burned in a room with windows opened, without danger.
A soldering copper may be heated in the glowing embers of a camp fire or in the embers in a fireplace.
Electrical Soldering Coppers.—The electrically heated copper is ideal for soldering as the heating coil is enclosed within the copper itself, the wire running out through the handle and connecting with an ordinary electric light socket. The heat is maintained at a proper degree for melting the solder; hence it is an ideal equipment for those who can afford it and where electric current is available. The doctors of certain hospitals have recommended electrical coppers for the use of patients in making tin can toys.
An electric soldering copper costs about $7.50 at the present time.
The Common Soldering Copper.—A suitable soldering copper or “iron” may be purchased at any good tool dealer’s or hardware store; it should weigh about one pound for work with the tin cans.
Almost everyone has purchased a small soldering outfit at one time or another and tried to solder the family wash-boiler or some leaky tinware; usually without success. Such outfits are invariably too small for large work or for the tin can toys.
It must be well remembered that the heat flows from the copper into the work, and that the copper has to heat up the work to the melting point of the solder; hence a large copper weighing several pounds is used to solder wash-boilers, tin roofs, etc., and a small copper weighing a few ounces is used for soldering jewelry, etc.
A large copper in expert hands may be used to solder very small work but a small copper may never be used to solder large work together, because the copper not only has to keep the solder melted to the flowing point, but also has to heat the work itself at the joint to the flowing point of the solder before the solder will leave the copper and adhere to the work.