Joint-wiping forms an important branch in the art of plumbing wovk which requires and practice than any of the other brancnes, and on it depends the success or failure of some of the most particular jobs in sanitary plumbing. Many serious cases of disease have been traced to bad joint-wiping. It is not expected that a joint can under all condi perfectly symmetrical and well as if it had been turned in a lathe. The best workmen have to leave joints that they would be ashamed of, as far as the appearance is concerned, if they were made on the bench or in some convenient place. There are too many who think that sound work is good therefore never try to make their work took as creditable as it should. The different styles of joint-wiping are so numerous, that one could go to any length describing the many eccentricities and peculiarities that are displayed in this particular branch of the trade. Of ery one has his own peculiar ideas in most matters, and no person does a thing exactly like another.
After a helper has been at the trade for a short time, his one great ambition is to wipe a joint. He seems to think that if he can only manage IB get a small portion of solder to adhere to a piece of pipe, and then so manipulate it as to induce it to take the form of an egg or a turnip, as the case may be, he has done something to be proud of, and soon begins to think he ought to be a full-blown plumber. Another question with regard to joints is the proper lengths to make them. Some like long joints others prefer short ones. The advocates of long joints say that are ugly, and are not proportionate. they often compared to nips, and other things not quite so regular in shape. Those who are in favor of short joints say the long ones are not so sound, that the will not stand a great pressure, and are liable to sweat. It is ridiculous to make joints of enormous length when a joint made more in proportion to the diameter of the pipe would not only be much stronger, but would look far neater, and generally require less solder. Then there is the question of wiping-cloths. A great many plumbers like a for wiping joints, but, on the many more say they cannot wipe thick cloths.
Many plumbers who are used to thick cloths and can wipe joints as easily as possible, are quite beaten if they try to use thin cloths. The difference in the thickness of cloths is very great in some cases. Very thin cloths are not suitable for making joints a nice shape. When a plumber gets used to a reasonably thick cloth he can make joints far better and easier than if he used thin ones. Generally, plumbers who use thin cloths make joints very short and lumpy, and bare at the ends, so that the shaving is shown about an eighth to three-eights from the ends. But when thicker cloths are used it is much easier to make joints more like the proper shape. This is very important in all joint-wiping, because wherever the shaving is left bare, the pipe is weaker here than any other part, whereas, if a joint is properly made, this part of it should be the strongest. In a large number of instances, when a pipe is subject to much expansion and contraction, it will break at this weak point very soon after it is fixed. It would be difficult to say generally what should be a proper thickness for cloths, excepting that they should be in proportion to the width and length. Cloths for large joints should be much thicker than those used for small ones, because the larger the cloth is, the more difficult it is to keep it in the shape required for wiping the joint. If a cloth used for making a four-inch joint were made of only about six thicknesses of moleskin, it would be no more, or at least but little more, use than one generally used for three-quarter or one-inch joints, because when a small amount of solder falls on it, the cloth would bend down and let the solder fall, so that the solder would not remain in the cloth except that caught in the middle, where the hand is under it. Consequently, there is much difficulty in getting up the great heat necessary to make a large joint. Then supposing it were possible to get up the heat sufficient to wipe the joint, it is useless to try to make the point as regular as would be the case if moderately thick cloth were used. The reason is, that when the cloth is hot it gives too much to the pressure of each finger, and therefore presses unequally on the surface of the joint, making it either bare at the edges and showing the tinning, or causing the body of the joint to be irregular and bad in shape, more especially at the bottom where it is nearly bare.
A cloth should be just thick enough to prevent the impression of the fingers having any influence on the body of the joint, but at the same time it should be thin enough to allow it to be bent the shape required without any great exertion. A cloth cannot be employed like a mould used by a plasterer to mould a cornice, if it could, it would not be so difficult, and require so much practice to make a joint as it does. Although there can be no doubt that suitable tools are indispensable to the workman, yet it must be remembered, by plumbers especially, that the cloth, however well made both in size and shape, will not make a joint without it is manipulated by an intelligent and experienced hand.