SEAMS
A description of the making of wiped seams for lead-lined tanks will not be attempted as very few are made now. The plumber, however, is often called upon to make a seam joining two pieces of sheet lead. The beginner will do well to go over the following exercise carefully and practice it thoroughly.
Materials.—Two pieces of 8-pound sheet lead, 6 by 10 inches each; one bar of 1⁄2 and 1⁄2 solder; paste, paper, and rosin.
Tools.—Rasp, shave hook, and soldering iron.
The 10-inch side of each piece is rasped and fitted together. The edges are cleaned and paper is pasted on leaving 1⁄4 inch for solder. Paste without the paper can be put on. This will make a joint 1⁄2 inch wide.
Apply the rosin to the joint, then with the heated iron and some solder tack the seam on the top, then on the bottom and middle. This will prevent the seam from spreading when the lead is heated. Solder and rosin can now be put on the full length of the joint. With a hot iron proceed to float the solder down the seam. The soldering iron must not rest at full length on the pieces of lead or it will melt the lead and render the work useless. The solder will flow and form a clean neat seam, if the iron is at the right heat and the right amount of solder is put on. If the iron is too hot, the solder will flow instantly when the iron is laid on it and the solder will disappear as it runs through the seam. If the iron is too cold the solder will not melt enough to flow. Too much solder on the seam will cause it to overflow, that is, the solder will spread beyond the papered edges. After a little practice this surplus solder can be drawn in on the seam with the iron and carried along the seam to some point that has not enough solder. When the seam is completed the edges should be perfectly straight and even. The iron is carried along the seam with one stroke which makes the seam appear smooth and bright.
CHAPTER III
Mixtures of Solders for Soldering Iron and Wiping.
Care of Solders. Melting Points of
Metals and Alloys
The importance of good solder, that is, solder correctly mixed and thoroughly cleaned, should not be overlooked. Work is more quickly and neatly done and the job presents a more finished appearance when solder that is correctly made is used.
The solder used in the following work with the soldering iron is called 1⁄2 and 1⁄2. This means 1⁄2 (50 per cent.) lead and 1⁄2 (50 per cent.) tin.
In the mixture of solder, only pure metals should be used. The lead should be melted first and all the dross cleaned off. The tin should then be added and mixed.
The solder to be used in wiping the joints in the following chapter is a mixture of 37 per cent. tin and 63 per cent. lead. This is called wiping solder.
The following table gives the melting points, etc.:
| Metal | Melting point | Mixture |
|---|---|---|
| Sulphur............. | 228 | Pure |
| Tin.................... | 446 | Pure |
| Lead................. | 626 | Pure |
| Zinc.................. | 680 | Pure |
| Fine solder........ | 400 | 50 per cent. tin, 50 per cent. lead (wt.) |
| Wiping solder.... | 370 | 37 per cent. tin, 63 per cent. lead (wt.) |
To recognize fine solder, run off a bar into a mold and let it cool. If there is a frosted streak in the center, the metal has not enough tin. The surface should be bright. To recognize wiping solder, pour some on a brick. When this is cool, the top should be frosty and the under side should have four or five bright spots. The amount poured on the brick should be about the size of a half dollar. If poured on iron, the metal will cool too quickly and show bright all over the under side.
To Make 1⁄2 and 1⁄2 Solder or Plumber's Fine Solder.—The possibility of getting pure clean metals to mix solder is very remote. Old pieces of lead pipe, lead trap, old block tin pipe are used to make solder when pure metals are not at hand.
- First, in a cast-iron pot melt the lead to about 800°, or a dull red.
- Second, clean off the dross.
- Third, add (to a 15-pound pot) 1⁄2 pound of sulphur in three applications. Each time mix the sulphur thoroughly with the metal with a long stick.
- Fourth, add tin before the last application of sulphur. Mix thoroughly.
- Fifth, pour off two bars and look for the frosty streak in the center. Add a little more tin, if necessary.
To Mix Wiping Solder.—
- First, proceed as described in 1⁄2 and 1⁄2, melting the metals and burning out with sulphur, adding the percentage of tin according to the preceding table. Then test the solder for bright spots on the under side.
- Second, keep the metal thoroughly mixed when burning and keep all dross cleaned off the surface.
The working heat of wiping solder is 500°F. Sulphur is used to collect all zinc and dross. The sulphur should come in contact with all parts of the metal. This is why the metal should be stirred when the sulphur is put in.
A few good points in the economical care of solder are listed below.
Care of 1⁄2 and 1⁄2 Solder.—
- First, do not drop melted solder on the floor or dirty bench.
- Second, use all small ends by melting on a new bar.
- Third, put clean paper under work and use droppings.
- Fourth, have the mold free from dirt when pouring.
Care of Wiping Solder.—
- First, do not heat red hot.
- Second, do not file brass where the filings will get into the solder.
- Third, do not allow lead chips to get into the solder.
- Fourth, clean the solder occasionally.
- Fifth, learn to distinguish solder from lead by its hardness.
- Sixth, have different-shaped pot for lead and solder.
- Seventh, do not tin brass by dipping into solder.
- Eighth, do not put cold or wet ladle into hot solder.
A pot holding about 15 pounds of solder is the size commonly in use.