The Soldering Bit.
—The average temperature required to make a satisfactory and thoroughly sweated joint in aluminium is from 650° F. to 680° F., according to the size of the article. A blowpipe or blowlamp will be of great value, and is frequently preferable to a bit. Should a bit be used, see that it is of aluminium or nickel instead of copper, the point and the soldered joint being kept much cleaner whilst removing the film of oxide during the soldering operation. Another advantage is that the point or “face” of the bit can be “tinned” with the same flux as that which is used for the joint. More care must be taken in the manipulation of the aluminium soldering bit owing to its lower melting temperature than the copper and nickel bits.