Do little rubbing or passing on the edges. Let the solder stack up; dig some out of the top of the mass with the ladle to temper fresh solder from the pot, so that pouring a liberal stream instead of drops will do no damage. When the pipe has absorbed enough heat to allow the cold masses at the edges to be lifted easily, pass the mass around a little so as to tin the cleaning. Keep plenty of solder on the cleaning, and let the edges take care of themselves until the last.

When there is a good mass of solder on the cleaning, and the edges are thick and mushy, do extra pouring on the edges to get them thoroughly hot, and then place the solder on the cloth upon the pipe. If it is hot enough, the solder will tend to run off at either side again; but it must be caught and pushed up. Then, with the aid of the thumb or an extra cloth in the right hand, push the solder around keeping plenty at the bottom, and get it patted up compactly into an egg shape with thick edges extending over on the soiled part, as quickly as possible. It may be necessary to pass or rotate the mass so as to get the cooler solder on the top to prevent it from dripping from the bottom. Experience will teach one how to mix the overheated portion with the balance so as to have the solder approximately at uniform temperature at all points by the time the joint is patted up.

The joint roughly shaped as described would hold water quite as well as after it is finished; but the appearance is bad.

Clean the edges first by pulling the cloth around, bearing down on one edge at a time. Then spread the middle and index fingers so as to let the cloth sag between them, and finish the joint by pulling the cloth around while bearing on both edges at the same time, keeping hold of the cloth by pinching it to the palm of the hand with the thumb. Beginners usually draw the cloth lengthwise of the joint to cut off the surplus carried around on the cloth by the finishing wipe; but an experienced person can finish the wiping while the solder is yet hot enough to sweat-in the cloth marks of the final wipe.

If the joint is wiped hot enough, and the heat evenly distributed, the tin spots on the surface when the joint is cold will be evenly distributed over the surface. If the pipe is hot enough, and the mass of solder too cold at any point, the friction of the cloth will cause the whole mass to rotate on the pipe. If too hot on the bottom, it will bleed the mass by dripping at the bottom. If too cold on top or at any other point, a very poor shape will result - if, indeed, one is able to wipe the joint at all. If the solder is fine, and a single wipe is made after the solder has fallen below the proper temperature, the surface will be covered with briar-like projections. If the solder contains any zinc, it will be brittle and work like cornmeal dough, and drip at the bottom when finished, if finished at all. All brass goods contain more or less zinc in alloy with copper, and it is best never to tin brass in wiping solder, as the zinc will melt out and ruin the solder.

Fig. 233. Butt Sweat Joint..

Fig. 234. Blow Joint..

Fig. 235. Copper-Bit Joint..

Fig. 236. Round Wiped Joint on Small Pipe..

Many plumbers use two cloths when wiping. To become expert with the cloth, it is better to wipe all kinds of joints with one cloth only, until thoroughly proficient; then, if a second cloth is found to be of real service in some instances, use it.

A beginner may take every advantage to aid him - such as choking a pipe to keep cold air from passing through, heating brass or copper edges with a torch before wiping, placing a live charcoal on a piece of screen wire within the pipe to aid in heating up, wiping large joints in sections and meeting the edges by chalking the finished part as described in connection with tank seams, etc. - but he should never be guilty of making extra joints in order to shirk a difficult position. The quickest plan to master this branch of work, is to make joints in whatever position they happen to be required, instead of trying to arrange an easy way.

Wiped joints should be made wherever practicable; but there are several other styles of joints equally serviceable for certain locations. Fig. 233 is a butt sweat-joint made by squaring the ends, tinning one end, and sweating the other to it by heating with a torch. It is the weakest joint made, but will at the outset stand any strain or internal pressure that the pipe itself will stand.

Fig. 237. Round Joint on Large Pipe..

Fig. 238. Branch Joint with Concave Neck..

Fig. 239. Branch Joint with Swell Neck..

Fig. 234 is a blow joint The only difference between it and the copper-bit joint shown in Fig. 235, is that the solder is floated by aid of the torch, and it is not so heavy as Fig. 235. The copper-bit joint is made with the soldering iron, the solder being melted and floated a little at a time until the joint is completed.

Fig. 240. Double-Branch Cross..

Fig. 241. Regular Cross-Joint..

Fig. 236 is a round wiped joint on §-inch supply pipe. For comparison a round joint on 5-inch soil-pipe is shown in Fig. 237. Fig. 238 is a supply-pipe branch joint with concave neck.