Hot Putty Knife and Screwdriver. The compound may be dug out with a hot putty knife. This is a slow, unsatisfactory method in most instances, especially in those batteries which use a considerable amount of sealing compound. With some batteries using only a small quantity of compound, a heated putty knife may be run around the inside of the jar between the jar and the cover. This will break the joint between the cover and the jar, and allow the plates to be lifted out. The compound is then scraped from covers and inside of jars, heating the knife or screwdriver whenever it cools off.
Lead Burning Flame. Any soft lead burning flame may be used. Such a flame may be adjusted to any desired size. Where steam is available, a flame should, however, never be used. The temperature of the flame is very high, and the covers, jars, case, posts, and vent plugs may be burned and made worthless. Even for the expert repairman, a flame is not as satisfactory as steam.
The Gasoline Torch. This is the most unsatisfactory method, and should not be used if possible. The torch gives a hot, spreading flame and it is difficult to prevent the covers, jars, case, etc., from being burned. Do not use a gasoline torch if you can possibly avoid doing so. Alcohol torches are open to the same objections, and are not satisfactory, even in the hands of a highly skilled workman.
If a flame is used for heating the compound, be sure to blow out with a hand bellows or compressed air any gas that may have gathered above the plates, before you bring the flame near the battery.
Electric Heat. Special electric ovens for softening sealing compound are on the market. The heating element is brought close to the top of the battery. Where electric power is cheap, this method may be used. Otherwise it is rather expensive.
When the sealing compound has been softened, place the battery on the floor between your feet. Grasp the two posts of one cell with pliers, and pull straight up with an even, steady pull. If the battery has been steamed long enough, the plates will come up easily, carrying with them the cover (or covers, if the batter has upper and lower covers) to which the compound is sticking, as shown in Fig. 196. Do not remove the plates of the other cells until later.
Rest the plates on the top of the jar just long enough to allow most of the acid to drain from them, Fig. 197. If you have removed the post seal, or if the seal consists of compound (old Philadelphia batteries), pry off the covers now with a screw driver. Otherwise, leave the covers in place while cleaning off the compound.
While the plates are resting on the jars to drain, scrape the compound from the covers with a warm screw driver or putty knife, Fig. 198. Work quickly while the compound is still hot and soft, and comes off easily. As the compound cools it hardens and sticks to the covers and is removed with difficulty. If the battery has sealing compound around the posts, this should also be removed thoroughly, both from the cover and from the post.
When you scrape the compound from the covers, do a good job. Do not scrape off most of it, and then leave pieces of it here and there. Remove every bit of compound, on the tops, edges, sides, and bottoms of the covers. If you need different sized putty knives or screw drivers to do this, use them. The time to remove all the compound is while it is still hot, and not after it has become hard and cold. If the battery has single covers, the compound can be removed very quickly. If the battery is of the old double-cover type, the job will take more time, since all the compound should be scraped from both top and bottom covers, Fig. 199.