Popular Science Monihli/ 



143 



How to Make an Electric Shaving-Mug 



THE general use of electricity in the 

 home has opened up a new fiolcl in 

 the way of cooking and heating utensils. 

 Such appliances are usually sui)i)]ic(i by 

 electrical houses, but many of the uten- 

 sils may be easily and neatly constructed 

 at home. One of these is the electric 

 shaving-mug. A mug or cup, capable 

 of standing heat, is the first thing 

 required. An aluminum cup of standard 

 shape and design, which may be pur- 

 chased in any town, will do perfectly 

 well. 



These cups are spun from a flat 

 sheet, and ha\e no seams to open or 

 leak. It is also necessary that no holes 

 be drilled in the mug, since it will be 

 utterly impossible to make such holes 

 watertight again. The heating element 

 must be fastened to the mug with a 

 clamp. This clamp will also allow the 

 heating-coil to be removed for repairs, 

 and makes it easily accessible at all 

 times. The bottom of such a mug 

 commonly has a flange, which makes a 

 recessed part, and in this the heating- 

 element is placed. The legs of the mug 

 are to be made of sheet brass, as shown 

 in Fig. I, one of the three having a hole 

 near the center for an insulating button 

 (Fig. 2), of "transite" or some other 

 material to hold the supply cord in 

 place. The clamp, for holding the 

 heating-coil, is shown in Fig. 3. This 

 clamp has a screw in the center to 

 tighten it in place. 



The heating-coil or element is depicted 

 in Fig. 4, which is a coil of flat "ni- 

 chrome" wire, or ribbon, as it is called, 

 12 ft. long, 1/16 in. wide, and 3 1 000 in. 

 thick. This is equal, in cross-section, 

 to a No. 26 gage wire. To wind this 

 coil, procure a block of wood, Jg-'i. 

 thick, about 4 ins. sq., with a J j-in. hole 

 in the center for an axis or pivot. 

 Clamp a 3^-in. rod in a vise so that the 

 block can be rotated around it. Begin- 

 ning at the center, fasten one end of 

 the nichrome ribbon to the block, 

 lea\'ing about 2 ins. surplus to make a 

 connection. Then proceed to wind the 

 ribbon in a spiral coil, .separating each 

 turn from the preceding one by a strand 

 of asbestos cord. 



A small section of this coil, as it would 

 appear higiily magnified, is depicted in 



— y/-r 





Details of the shaving-cup and construction 

 of the heating-coil 



Fig. 5, where /I, or the lightly shaded 

 part, represents the asbestos insulation, 

 and B, or the black lines, the ribbon. 

 This asbestos insulates each turn of the 

 coil from the next nearest, and the 

 electrical current must travel entirely 

 through the resistant element, instead 

 of jumping from one turn directly to 

 another, which would be the case, if 

 insulation were not used. The coil 

 must be very closely wound, in order to 

 get it into the very limited space in the 

 bottom of the mug. 



Before taking the coil from the block, 

 rub into its surface a little asbestos 

 retort cement, or a cement composed of 

 a mixture of silicate of soda and silica, 

 or glass sand. This mixture, when dry, 

 will tend to hold the coil together, and 

 the current may be passed through the 

 coil, to test it, as well as to bake it in 

 its coiled shape. The support for the 

 coil is a disk made from a piece of 

 5/'i6-in. asbestos, wood or transite. Cut 

 it to fit into the recessed part in the 

 bottom of the mug. Then with a chisel, 

 remove enough material from the top 

 of this disk to form a depression, 1/16 



