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.

Air Holders.

Different lead burners have different views on this subject. Some prefer the bellows, with a contained air holder; some the air holder built like a gasometer, while others use an air holder similar to the generator in construction. These all have their advantages. For my part, I own and use all three.

The advantage of the bellows is that it can be easily transported and does the work perfectly, but it requires constant pumping, which soon tires the helper, and for that reason could not be used on jobs requiring more than four or five hours' labor.

The gasometer style of air holder is the easiest to use, if one does not employ a helper and has a large amount of work to do. The pressure can be regulated to suit the work by placing one or more weights upon it until the desired pressure is obtained. It does not require pumping up more than three or four times a day, which is its principal virtue. It is a perfect shop apparatus. Its disadvantage is that it requires a large quantity of water to fill it, which is not always available, and when full it is so heavy that it requires a truck to move it around.

By far the best air holder is the one shown as part of the apparatus in Fig. 9, and illustrated separately in Fig. 10. This only requires a few pails of water to fill it, and the exact pressure of the gas can be had by building it the same hight as the hydrogen gas generator. It does not require constant pumping, and I recommend this air holder for general use, as possessing more advantages, with less trouble, than any other air holder in use. However, all three will be described, and the beginner can make the one most suited to the material available.

Air Holder No. 1.

The beginner will notice in Fig. 10 that this air holder is so constructed that it gets its air pressure direct from the head of water, and also that this pressure can be varied by making the connecting piece of pipe longer or shorter, as may be desired. Of course, the pressure will vary slightly as the water descends into the air chamber, but not enough to make it objectionable, as it will be the helper's duty to watch the water line and renew pumping as often as the water falls below a certain point.

To make this holder, a tank, _a_, Fig. 10, 12 inches high and 18 inches in diameter, should be constructed of galvanized sheet iron. On this tank double seam a flat bottom. The top must be raised slightly, as shown, to give it strength. This can be done with the raising hammer, or it can be done by making the circle for the top ¾ inch larger than the bottom, then making a cut to the center. It can then be drawn together and riveted in any desired pitch. A hole must be punched in the center of this top large enough to receive a 1-inch galvanized pipe, _b_. Six inches apart and 2 inches from the edge punch two holes, _c_ and _d_, large enough to receive pieces of ⅜-inch galvanized pipe. This top should then be fitted and placed on the body of the tank.

Take a piece of 1-inch galvanized pipe, _e_, sufficiently long to touch the bottom and projecting 1 inch out of the top of the tank, cut a thread on the projecting end and drill the other end full of ¼-inch holes, _f_, to the hight of 1 inch, to allow the water to flow freely. This pipe rests on the bottom of the lower tank and carries the weight of the upper tank. Solder this pipe in place. Then take two ⅜-inch nipples, 1 inch long, and solder them into their places, and on these nipples screw two ⅜-inch hose end gas cocks, _c_ and _d_. One of these cocks is for the purpose of connecting to the air pump, and the other to the mixing cock. As close as possible to the bottom of the tank solder in a ½-inch coupling, _g_. Into this coupling screw a plug. This is for the purpose of draining the tank when out of use.

Now make another tank, _h_, 19 inches in diameter and 11 inches deep, the top to be left open and wired with a heavy wire. Double seam a flat bottom on this tank. Directly in the center of this bottom punch a hole large enough to receive a 1-inch coupling. Then cut a 1-inch coupling in half and solder it into this hole, putting the thread side down and leaving it as near flush with the outside of the tank as possible, so that if it is desired to move the air holder to and from a job it can be taken apart and the lower tank nested in the upper tank, making a compact bundle and reducing the danger of damage by careless handling.

To connect these tanks, all that is required is a piece of 1-inch iron pipe, _h_, 12 inches long, with a coupling on one end. To operate this air holder, close the two air cocks on the lower, or air, tank; then fill the upper tank nearly full of water, taking care not to put too much in it, or it will overflow the lower tank and get into the tubes, and if this happens the tubes will have to be removed and hung up to dry, or drops of water will be blown into the blow pipe and extinguish the flame. It is then ready for use. The air in the air chamber is compressed by the weight of the water in the upper tank, and if the water line is at the same hight as the acid line in the hydrogen gas generator the pressure of air must be the same as the pressure of gas. As air is used the water descends through the pipe and will gradually fill the lower chamber. It can then be forced back into the water chamber by attaching the air pump to the cock _h_ in Fig. 9, or _d_ in Fig. 10, without disturbing the gas or in any way interfering with the operator. To connect with the cock _h_ in Fig. 9 it is only necessary to disconnect one line of hose and connect the pump; then close the other cock and work the pump until air bubbles up in the upper tank; then shut the cock, remove the pump and connect the hose to the gasoline can, open the cocks and the apparatus is ready for use.

Air Holder No. 2.

To make the air holder shown in Fig. 11, take a sheet of No. 26 gauge galvanized iron 30 inches wide. Make it into a cylinder 26 inches in diameter, double seam a flat bottom on it, and wire the top with ¼-inch iron rod, which will make it stiff enough to withstand the pressure of water. Close to the bottom and 3 inches apart punch two holes, _a_ and _b_, large enough to receive ⅜-inch galvanized pipe couplings. Solder these couplings in place.

On the inside of this tank and into these couplings screw two pieces of ⅜-inch pipe 4 inches long with elbows pointing straight up. Into these elbows screw two pieces of ⅜-inch pipe long enough to come flush with the top of the tank F. On the outside of the tank and into the ⅜-inch couplings screw two ⅜-inch nipples 2 inches long, and on these nipples screw two ⅜-inch hose end gas cocks.

Now, with the same sized sheet iron, make another tank 2 inches smaller in diameter than the first tank. This should have a flat bottom, and be wired as previously described. Then take four strips of sheet iron 30 inches long and 2 inches wide, and form each into V shape lengthwise. Lay off the circumference of this tank in four equal spaces. One side of the V-shaped pieces should then be soldered on at each space. The other side should be left loose to allow for adjustment. These pieces form the guides to the upper tank and prevent it from tipping sideways and binding. Two of the guides are shown in the illustration, Fig. 11.

The lower tank should now be filled about one-third full of water. The upper tank should then be inverted and placed in it. The air pump must then be connected to one of the ⅜-inch cocks with a short piece of hose, and the air should be pumped into it until the upper tank rises to its highest level.

The pressure in this form of air holder must be regulated by weights, and to secure 1 pound of pressure it is necessary to place weights equal to 1 pound for every inch in area contained in the opening in the upper tank. Two drop handles, such as are used on heavy milk cans, should be riveted and soldered on the sides of the tank to facilitate moving it about.

Air Holder No. 3.

Fig. 12 is a cut of a bellows with a contained air holder. It is not practical to try to make this article, as it can be purchased from any plumbing supply house and is not expensive. It is used principally by dentists, but it is also used in laboratories to supply air to the compound blow pipe. It consists of a small bellows held from the floor on iron legs, with a spring inside the bellows to hold them open, and has a rubber bag fastened to the under side to hold a small supply of air. The rubber bag is incased in a string net to prevent it from becoming inflated too much and bursting. This bag serves to equalize the pressure. The size known as No. 10 A will supply 75 cubic feet per hour at a pressure of 1½ pounds to the square inch, which is sufficient for lead as heavy as 24 pounds. For the light weight leads the pressure can be reduced by pumping lightly and not filling the bag more than half full.

Any of the three described air blast arrangements will answer the purpose, so it is immaterial which is used, and it is left to the discretion of the beginner to obtain whichever is the most convenient.

The Blow Pipe.

Next comes the blow pipe. The only practical compound blow pipe on the market is shown in Fig. 13, and is known as Walmsley's. This is a modification of the Bunsen burner, and consists of a bent blow pipe with the air tube in the center, as shown in Fig. 14. It is a perfect working blow pipe in every respect, and I should advise every one interested in the work to purchase one. For while seams cannot be burned with it in any other position than horizontal, it will be found useful in lengthening traps or lead bends, for which purpose it is well adapted and can be put into instant use, thereby saving its cost many times over in wiping solders.

Burning with Illuminating Gas.

With illuminating gas it is only necessary to connect the gas jet to the compound blow pipe with the hose and regulate the supply of gas with the gas cock. The air inlet is then connected to the air holder, or air may be supplied with the mouth, but good results are not obtained with the mouth, as only a good blow pipe solderer can keep up the blast necessary. To burn the seams use the same flux and follow directions given for gasoline gas.

Making the Gasoline Gas for Burning the Generator.

With a piece of ¼-inch hose connect the top of the can C, Fig. 9, with the air holder D, then connect the spout or gas outlet _e_ of the can to the gas end _f_ of the compound blow pipe. The air outlet _g_ of the compound blow pipe should then be connected to the remaining cock _h_, in the air holder. If the bellows is used, it will be necessary to connect the air with ¼-inch tee, _m_, in which three short nipples have previously been screwed.

The apparatus is now ready for use. Gasoline being really a liquid gas, it takes its first opportunity to assume its natural shape. The natural way to convert gasoline into gas is by simple evaporation. So taking advantage of this fact, the action will be thus: By forcing air into and through a body of gasoline sufficient of the gasoline is taken up to form a dense vapor, which will light and burn at the jet, similar to illuminating gas. With the admixture of air in the compound blow pipe, it gives a flame of very intense heat. But, in common with illuminating gas, it is so rich in carbon that it gives an oxidizing flame, and makes it necessary to use a flux, which should be Yager's soldering salts mixed as per the directions on the bottle. If this is difficult to procure, a good substitute can be made by mixing equal parts of powdered borax and sal ammoniac in a little water.

To operate this device the air should be turned on the gasoline and lighted at the jet. The air should then be admitted gradually until the flame is brought to the proper size and condition, indicated by its being blue and pointed. If too much gas is admitted the flame will be yellow and will blacken the work by depositing a coat of soot on it. If too much air is admitted the flame will be ragged and noisy, and the temperature will be too low to heat the metal. The flame is at its best heat when it burns with a pale blue color which does not show any yellow streaks.

Before attempting to burn the generator the beginner should practice on pieces of sheet lead. It is next to impossible to burn seams in any other position than horizontal with this flame, as it rapidly oxidizes the lead, and in spite of all precaution the lead will become unmanageable in upright seams, so that the beginner would waste time in practicing on seams in any other position than horizontal. If directions have been followed in cutting the lead for the generator the seams will occur only in that position.

To burn the generator the seams should be shaved clean, both on the under and upper sides, for a distance of ⅛ inch, making a seam ¼ inch wide, taking care to have the lead seams lie close to each other, for, if they do not, this flame will cause the edges of the lead to spread away from each other and leave a hole that is difficult to patch.

Now apply the flux with a small brush. When the flame is in working order bring it quickly to bear on the end of the seam nearest you to be burned. When it starts to fuse draw the flame as quickly away, always drawing it to one side, and from the upper to the lower sheet. The melted drop will follow the flame and unite with the melted drop on the lower sheet.

It is necessary to have the shave hook near at hand, so that, in case of oxidizing when fusing, the melted drop can be broken up and allowed to flow in place.

With a little practice and patience the generator can be burned all right in this manner. This gas is perfectly safe and can be handled with impunity. This method would, of course, be impracticable to use on a job of any size, but I have used it several times where nothing else could be obtained, and have always had very good success with it.