Brazing-lamps.
—These lamps are constructed to burn benzoline or paraffin, and the more powerful types are fitted with pumps so that air pressure may be exerted on the oil. The paraffin or benzoline is thus forced into the burner, and by passing through the previously heated tubular coil is converted into gas, which issues forth out of the gas nipple, mixes with air, and then burns with a blue atmospheric flame of high temperature. After filling the lamp, a torch should be held under the burner to vaporise the oil, and thus ignite the lamp, after which pressure is applied by means of the pump. Do not start pumping too soon—that is, before the burner is sufficiently hot to vaporise the oil—or the oil itself will be forced through the gas nipple. The flame may be regulated at will, to suit the work in hand, after the burner has become thoroughly hot to set the lamp fairly going. When brazing, lay the article to be brazed on some broken coke, charcoal, or firebrick, and if the article is comparatively heavy, cover it over with some small pieces (to conserve the heat) except where the brazing is required. After applying flux and spelter to the previously cleaned metal, direct the flame of the lamp on it, gently at first, until the spelter fuses and makes the joint.