This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
This has been already described under its alternative title of Overlapping Joint. It possesses the advantage over the roll joint of not taking quite so much lead - the height of the two turned-up edges not being necessarily more than 1¾ in. and 1¼ in. respectively - besides which it forms a less inconvenient and unsightly joint for terraces and the floors of balconies and verandahs, inasmuch as it projects less than the roll above the general level, and is consequently less likely to occasion accidental trippings.
Wiped Joint is so called from being made with the aid of a soldering cloth or wiping cloth formed out of a piece of old or new canvas, fustian, moleskin, bed-ticking, etc, folded into several, say 8 or 9, thicknesses so as to constitute a pad about 5 in. by 4 in., or any other size considered more convenient by the artificer. This is well saturated with tallow by holding it before the fire and rubbing the grease in, or else by placing it in a vessel exposed to gentle heat with the tallow on the top of it, but it matters not what the method is so long as it results in the cloth becoming perfectly soaked, soft, and pliable. The grease, which must be renewed as required, prevents the solder from sticking to the cloth, and imparts the suppleness essential to its proper manipulation by the plumber in order that he may wipe the solder to any form or do, in fact, anything he chooses with it when brought by the iron to the proper buttery consistency. The solder, or pot metal, or metal as it is commonly called in the trade, that is used with this cloth is a coarse variety of soft solder made by melting together 2 parts of lead and 1 of tin, or thereabouts. It must not be allowed to get red-hot, which tends to harden the metal and render it liable to easy fracture, nor must any zinc whatever be permitted to get into the pot, else the whole will become too brittle to work and be spoilt. In order that the solder should not stick where none is required, a mixture of thin glue and lamp black, or some equivalent compound called " soil," "smudge," or " tarnish," is applied with a small brush such as a sash tool for a depth of about 3 in. or 4 in. from the edge of each piece to be joined; but previous to laying it on any grease, accidental dirt, etc, is removed with a piece of chalk, and a rubber of cardboard or thick paper. After the smudge has quite dried by holding near it a hot iron, or by other or natural means, the parts of the work to be united must be prepared and fitted - if of pipes, as explained under Taft Joint - and then for a distance back of about 1 in. or 1½ in. from the intended line of junction they must be carefully scraped with the shavehook clean and bright, and immediately greased with the " touch " or piece of tallow candle to prevent retarnishing. If sheets are to be joined, their edges lying in the chase cut in the boarding for the flush soldering must be similarly prepared, and so must each and every edge that is intended to be united by this kind of joint. The soldering iron being brought to a bright red heat, the solder melted so as to pour off in a bright and silvery looking stream, the scale filed off the iron, the wiping cloth warmed and greased, the ends or edges of the work properly adjusted and firmly held in place, and moreover assuming the joint about to be made a flush soldered one and the weather fine or dry, a ladle full of the metal, not too hot to melt the lead, is poured along over about a foot length of the joint, more metal being really required to raise the work to the proper temperature so that it may become thoroughly well tinned than for absolutely making the joint, the surplus being always, however, returned to the pot. The plumber with the wiping cloth in his left hand presses the solder into place, whilst with the right he works the hot iron backwards and forwards, remelting the solder and bringing it to a soft plastic consistency admitting of being wiped or fashioned at will to any form, and which in this instance is simply a smooth flush surface. In the case of an underhand pipe joint, the wiping cloth is held under the joint and the solder poured in a fine stream along and about the region of the joint, and not all in one place, whilst with the cloth it is pressed around it, notwithstanding much drops and falls off and is skilfully caught by the cloth, the pouring being continued till a sausage-like lump remains. The hot iron is energetically plied backwards and forwards round and about until the solder is brought to the soft state just spoken of, when it is wiped or finished off in the form of a symmetrical knob somewhat egg-shaped, with a thickness of solder at the centre of about ⅜ in., dying away into the pipe in a well-defined line, as shown in Fig. 150. Sometimes the position of the pipe is such as to require the copper-bit to complete the joint. In making a wiped joint with the blowpipe or blowing lamp and strip solder of the same coarse description as that used as above in the molten state, a single thickness of cloth is all that is required, the flame melting the solder, which drops on the joint and raises the work to the proper heat and the solder to the proper temper, so that the former may be well tinned, and the latter distributed about the joint to enable it to acquire the desired shape and soundness. When enough 6older has been deposited on the joint, however, it is still necessary to maintain the heat with the flame whilst the proper symmetrical shape is imparted to the joint with the cloth.