The Art of Lead Burning / A practical treatise explaining the apparatus and processes.

by C. H. Fay

Building the Frame.

The frame can be made of galvanized iron, but wood is much superior, as it retains the heat generated in the gas chamber much better. To make the frame take the ⅞-inch board and cut off two pieces, 10 inches square, A and B in Fig. 8; 5 inches from one side and 2 inches from the back of one of these pieces bore a 1½-inch hole, C, and countersink it. This is for the acid supply pipe to pass through. These pieces are intended for shelves upon which to rest the acid and gas chambers. Cut the remaining board into two pieces 38 inches long. Lay these two boards together. Five inches from the side and 3 inches from the bottom bore a 1½-inch hole, d. Then saw out a V-shaped piece, Fig. 7. This will form the legs of the generator.

Fig. 7.—Making the Acid Chamber.

Take a square, and 12 inches from the top of these boards draw the lines e and e. Twenty-two inches below these lines draw the lines f and f. These lines represent the tops of the shelves. The shelves should be nailed or screwed into place. The shelf B should be placed on the top, keeping the hole C to the back. Take the ½-inch board and cut two pieces to measure 12 × 13 inches and two pieces 11 × 12 inches. These form the sides of the acid and gas chambers. The two 12 × 13 inch boards form the sides of the acid chamber and the 11 × 12 inch boards the sides of the gas chamber.

Directly in the center and 1¾ inches from the bottom of one of the 11 × 12 inch boards bore a 1½-inch hole. The remaining piece should be sawed out, leaving a hole at g. This is so that the board can be removed in case of a leak without disturbing the cleaning screw. These pieces should be fitted to their places with round head screws, and if properly done will form an acid chamber which will measure 10 × 10 × 12 inches, and the gas chamber will measure 10 × 10 × 10 inches. The acid chamber must be larger than the gas chamber, to allow the full charge of acid to be used without overflowing.

Fig. 8.—Making the Shelves and the Perforated Bottom.

Now fit the sheet lead. Six-pound is plenty heavy for this generator and will last a lifetime. Cut it as shown in Fig. 8, A and B. Form the lead so that the seams when finished will come on the outside, as in case of a leak in a seam it can then be easily repaired by removing one of the boards. The projecting edges of lead should be dressed over the edges of the top to protect the wood from the acid, but do not fasten them, as the tanks will have to be removed and the seams burned.

Now cut the piece of lead C to form the top of the gas chamber. None is needed for the acid chamber, as it must be left open so that no resistance will be offered to the action of the gas on the acid. Five inches from the side and 2 inches from the back of this piece cut a hole, d, Fig. 8, 1¼ inches in diameter, and dress it up with the bending iron to 1½ inches in diameter, taking care to preserve the thickness of the metal. This is for the acid supply pipe to pass through.

Three inches from the side and 3 inches from the front cut a ⅛-inch hole, e. This is the gas outlet. Three and one-half inches from the opposite side and 4 inches from the front cut the hole f, 2¾ inches in diameter. Dress this up and over the flange of the charging screw a, Fig. 6. This may seem a difficult thing to do, but lead must be worked slowly. Heating the lead while dressing it will help wonderfully. If it is not possible to make a good job in this manner, then cut the hole 4 inches in diameter and burn in a collar sufficiently big to dress over and cover the flange of the screw. This is to prevent acid from coming into contact with the screw and destroying it. Treat the cleaning screw in the same manner. The location of this screw is in the center and as close as possible to the bottom of the gas chamber, as shown in Fig. 8 at j.

Fig. 8½.—Showing the Perforated Spelter Shelf in Place in the Generator.

It is necessary to have a false perforated bottom in the gas chamber to rest the zinc upon and also to keep it above the solution. To make and support this bottom take a piece of sheet lead 14 inches square, as shown in Fig. 8, and form it in the shape of a pan, which will drop easily into the gas chamber k, Fig. 8½. A piece of 1½ or 2 inch lead pipe, 2 inches long, n, should be burned on the center of the false bottom, to prevent the center from sagging with the weight of zinc. Then punch the bottom O, Fig. 8, full of ¼-inch holes. A 1½-inch hole, y, should also be cut in line with the holes for the acid supply pipe.

Remove the tanks and burn the seams. Place the tanks back in place. Then take a piece of the ⅛-inch brass pipe, 1½ inches long. Cut a thread on one end, tin the other end, and burn it to the top of the gas chamber at e; also the collar for the charging screw. Then place the perforated bottom in the gas chamber, taking care to keep the holes for the acid supply pipe in line. Do not make any mistake in putting in this bottom. Its use is to act as a shelf to hold the zinc, and if put in properly it will hold the zinc about 2 inches above the real bottom. The top of the gas chamber c should then be burned in. Now by measuring find the exact length of the acid supply pipe, Fig. 7, i. This pipe should extend from the bottom of the acid chamber o to the bottom of the gas chamber p, as shown in Fig. 7. From one end of this pipe several V-shaped pieces should be cut, p, about 1 inch deep.

This is one of the most particular parts of the apparatus, as this is where the automatic action comes in, and great care must be taken in cutting these holes not to have any of them come closer to the perforated bottom than 1 inch. If this were not observed the acid would be constantly in contact with the zinc, and would rapidly get up pressure of gas sufficient to blow acid out of the upper tank, and the extra gas would escape through the acid supply pipe in blows. In fact, it would make the generator useless. This is the trouble with the French apparatus. The acid, having no place to expand in, is constantly coming into contact with the zinc, and unless the gas is being used as fast as generated it will blow acid out of the acid holder, making a bad mess, besides being very wasteful.

Now flange the other end of this pipe to fit the countersunk bottom of the acid chamber. Place the pipe in position and burn it to the bottom of the acid chamber and to the top of the gas chamber n, Fig. 7. One of the ⅛-inch gas cocks should be screwed on the brass nipple on top of the gas chamber. This will complete the gas generator. It will make a better job if the back of the generator be boarded tight and a door made to fit the space between the bottom of the acid chamber and the top of the gas chamber in front. It is very convenient to have it fixed in this manner, as in shipping it from one point to another the tubes and other incidentals can be placed in the space so made and shipped with safety. There is no objection to the acid and gas chambers being made in the shape of cylinders, instead of square, if so desired, but if made circular they should be made to fit the frame tightly to prevent jarring and eventually breaking the seams.

CHAPTER V.
MAKING THE GAS TO BURN THE GENERATOR.

In towns supplied with illuminating gas it is a comparatively simple operation to burn the lead lining for the generator, but for the convenience of those who cannot obtain gas it is necessary to give some method by which the generator can be burned. The method described will answer for illuminating gas as well as for gasoline.

To generate gas from gasoline is a simple operation. To do this, take a common 1-gallon oil can, remove the top of can screw and punch a ¼-inch hole in the center of it. Then make a tube of tin that will pass through this hole, sufficiently long to extend half way to the bottom and project 2 inches outside of can screw, and solder this tube in place. This projecting tube is for the purpose of connecting to the air holder. Remove the spout of the can and replace it with one to which the hose can be connected. Now fill the can two-thirds full of gasoline, but not full enough to cover the gas outlet, else it would be likely to force gasoline out instead of gas.

After this is done, screw the can screw in place, the long end of the tube extending into the gasoline, as shown in j, Fig. 9. A hose connection is now to be made with an air holder. As it is necessary to have an air holder both for this process and the hydrogen gas process, methods will be described for making air holders which can be used for either.

Fig. 9.—Gas Apparatus for Burning the Generator.