A Homemade Blowtorch 1094

The torch shown in the sketch requires no air pump. Instead of forcing a small stream of gasoline into a heated burner it converts the gasoline into gas in the chamber and blows a small jet of it through a very small hole into the combustion chamber. A medium-sized and strong oilcan is used for the reservoir, the spout being cut off close to the screw part and a steel or brass tube, about 5/16 in. in diameter, soldered to the stub end. The tube is bent as shown. A piece of wicking is drawn into the tube so that the upper end is within 1/4in. of the tube end. The end of the tube is then fitted with a piece of brass rod with a very small hole in the center. The hole is made in the following manner: Before the piece is cut from the rod, it is held in a vise and the sharp end of a scriber is carefully driven into the center. A little oil placed on the scriber point will keep it from sticking in the metal. Measure the depth of the hole and cut the rod off just above the point. File the end of the piece cut off with a fine file until the point of the hole is reached. This hole must be so small that light can be barely seen through it. The combustion chamber is made of a piece of brass tubing driven over the end of the smaller tube on the spout. About 1/2in. from the back end of the larger tube four or more holes are drilled to admit air to the gas.

Fill the can about three-fourths full of gasoline and allow time for the wick to become saturated to the upper end. Hold a lighted match to the rear of the burner, and the heat will convert the gasoline into gas which will then burn with a nice white flame about 1 in. long. The success of the torch depends altogether on the fineness of the hole in the end of the tube and the tight soldering of all the joints.