Page:Popular Mechanics 1928 01.pdf/124

 may also be obtained from the same place. The plates should measure 5$1/2$ in. from top to bottom, disregarding the lug at top, and should be 2 in. wide. Saw out these sections, including the lug, as shown on this page; by following down one of the individual lines separating the columns of paste inserts, a straight cut is assured. To further reduce the cost, a second plate. 2 in. wide, can be cut from the remaining section and a lug soldered to the top, but this is not advised. Three negative plates and two positive plates are required for each cell, therefore, when buying the plates for the three-cell job ask for nine negative and six positive plates. The negative plates come pasted with pure, spongy lead and will have a gray color, the positive plates are a chocolate-brown color, the paste filler used being peroxide of lead. Wood or rubber separators can also be obtained from the battery-service station or garage; these are cut down from standard sizes to 7 in. long by 2 in. wide and four are required for each cell, as shown on page 121.



The plates are now assembled, first a negative, then a separator, then a positive plate with the lug on the opposite side, then the separator and so on, until three negative and two positive plates are assembled. All positive lugs should be on one side and all negative lugs on the other; snap two large rubber bands around the unit at top and bottom to hold them together. The plate bars, or lug connectors, are made from heavy sheet lead, cut and bent in the manner shown in the illustration above. The plate lugs are soldered in the slots shown; this operation is simplified by clamping the units in a vise and using a large, hot soldering iron and plenty of solder. Care should be taken not to connect positive to negative plates in any way by dropping solder between them. The upright strip of the plate bar is drilled for bolting to the connecting strap as shown in the sketch; these connecting straps of heavy sheet lead being 1 in. wide and long enough to reach from one jar to the other. The plate bars soldered to the lugs extend across the edge of the jars and support the assembly in each cell; the top view on page 121, at lower right, shows all three units in position, with the connection straps across the partitions connecting the cells in series. When the cells are assembled in the case, the negative plate of one cell should face the positive plate of its neighbor; the connecting straps, drilled at each end, are then bolted to the plate bars with brass bolts and nuts, 