A CHEAP LABORATORY SODIUM PRESS E. H. PARRE,OBERLINCOLLEGE, OBBRLIN, OHIO A very simple sodium press for laboratory use can be made as follows: A piece of three-fourths inch gas pipe of convenient length (three or four inches will serve), machined on the inside sufficiently to insure smoothness and uniformity of bore, is used as the cylinder of the press. It is threaded a t each end to accommodate regular pipe caps. One end must be threaded far enough that the cap will screw on until the end of the cylinder is tight against the inside end of the cap. Through this cap drill a small hole of l'/%or 2 mm. diameter through which sodium can be forced in wire The other cap must be drilled and tapped with a 3/9" pipe thread. A piece of 3//s" pipe about five and one-half inches long is now threaded its entire length t o screw into this cap. A piece of iron rod of such size as will go tightly into this pipe is fitted %" therein with a half-inch protruding, and ground to a beveled point. On the other end of this pipe is fitted a Thandle by using a gas "tee" with short pieces of pipe screwed into it. It is well to put a small stop in the "tee" between pipe handles for the piece in the other side of the "tee" t o screw against. This may be made of a onehalf inch length of rod or pipe. Drill through the side connection of "tee" and rivet it, thus making this connection permanent. Machiie a steel plug as a piston block one inch long to fit as tightly as will work conveniently inside the three-fourths inch cylinder. Make a shallow indentation with a S/8-inchdrill in one end of this plug in which the beveled end of the screw will work. To insure an absolutely tight fit a composition gasket may be fastened to the front end of this plug with a machine screw. The pieces are now ready for assembling. Place the small block in the end of cylinder with the shortest threading, indented end out. Next screw on the cap with the tapped hole and into it connect, with a few turns, the 'I-handled screw which is to be the piston shaft of the press. The next operation is to fill the cylinder with freshly cut sodium. The
-
4
VOL.4. No. 7
A CHEAPLABORATORY SODIUMPRESS
919
pieces should be cut as large as possible, a square piece may be rounded with a wood mallet. After the cylinder is filled, as quickly as possible screw the cap on tightly for this end of the cylinder. The press is now ready for operation which is accomplished by screwing in the piston, and the sodium wire will exude through the small hole in the other end. If measurements are correct the cylinder will be empty when the Thandle comes against the cap into which the piston rod screws. To refill, unscrew the piston rod until nearly out, push back the piston block and fill as before. This press has been satisfactorily used in this laboratory for several years.
