This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
To make a foot-warmer, cut a piece of No. 22 or No. 24 sheet copper to 22 in. long by 12 in. wide. Scour it thoroughly with wet sand, and tin one side of it over a coke fire with block tin, using sal-ammoniac as a flux. When tne tin has alloyed itself with the surface of the copper, wipe off with a pad of tow, and immediately immerse it in clean cold water, afterwards cleaning with silver sand, and then drying with hot sawdust. Punch a hole for a feeder screw A (Fig. 1) in the centre of the length Hin. from the edge. The copper should now be planished with a planishing hammer on a tinsmith's bright anvil. This will close the " grain," thus increasing the durability, as well as developing a bright, smooth surface. Two edges opposite each other should now be set off the ends on a hatchet stake, so that when the copper is bent to shape the edges will clip each other. The bending can best be done over a narrow mandrel, and the edges must be " grooved " inside. When this has been done the section will appear as in Fig. 2. Solder the feeder screw in the hole from the inside, and similarly the grooved joint, leaving a good body of metal on each. This constitutes the body of the foot-warmer. To make the ends, up-end the body on a piece of copper, and mark around. Allow a 1/4-in. edge extra, cut the copper, and mark and cut out another one from it. These pieces should be cleaned, tinned, and planished, etc., as previously described. Then they should be slightly hollowed (both together) on a wooden block with a hollowing hammer. Now crease or " jenny " the edges so as to fit the body tightly. Before these pieces are finally fixed, two handles B (Fig. 1) must be made from No. 8 brass wire, each with a copper plate which is riveted to the end, as shown. Solder over the heads of the rivets inside, fit each end on, and solder well round. The superfluous solder may be removed by a steel scraper or a smooth file. Rub well with emery sloth, and finish with crocus and oil.
Making Copper Foot-warmer.
 
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