How to Make a Vacuum Pail
As a substitute for a vacuum bottle a very efficient pail can be made in the following manner: Procure a 1-gal. sirup pail for the outside and a ¹⁄₂-gal. size for the inside. Make a collar of tin, as shown, with projections; bend these down, inside and outside, then solder the collar to the inside of the larger pail, and the smaller pail to the inside of the collar. Be sure to make a perfectly air-tight joint in the soldering. This gives a double wall with an air-tight space all around the inner pail, or opening. To make vacuum covers for the pails, take two covers of each size and solder them together, as shown.
A Two-Wall Pail with Covers in Which a Partial Vacuum is Made
To produce a vacuum, make a small hole in the metal forming the collar, also one in each cover. Put a few drops of water in each vacuum compartment and set the parts on a heated surface. When the steam escapes, solder the holes. This will produce a partial vacuum in the space around the inner pail and in the covers. This will make a very efficient vacuum pail.—Contributed by John H. Spicer, Magnolia, Ark.