CHAPTER XXVI

SOLDERING. SCREW STEAMER. TOYS WORKED BY WIND AND BY CONVECTION CURRENTS

=Soldering.= A knowledge of soldering makes many more toys possible, besides being a useful acquirement in itself. The following are the materials needed:

1. A soldering iron (Fig. 513). This can be bought for sixpence at any ironmonger's. It is best to get one not too long in the stem, as otherwise it is difficult to hold it steady.

2. A strip of soft solder, price about three-halfpence.

3. Soldering fluid or flux. This can be made at home from a pennyworth of spirits of salt (from an oil shop). Put a little of the spirits into a separate bottle and drop a few scraps of zinc into it. When it has stopped "fizzing" it is ready for use.

4. A pennyworth of resin.

5. A piece of sheet tin.

Soldering is not nearly so difficult as people think. There is one thing really essential for its success, and that is unlimited patience in cleaning the metal surfaces to be joined together. Solder will not adhere to dirty metal. The surfaces must be thoroughly scraped and cleaned with an old knife, then filed, rubbed with emery-cloth and protected by a coating of flux. The flux required for use should be kept in a shallow dish (_e.g._ a meat-paste jar), to prevent it being upset; it can be put on with a small brush.

The copper bit of the soldering iron must be covered with a thin film of solder before any soldering is done; this is to ensure that it is perfectly free from dirt or dust. This process is called "tinning the bit." It is quite simple. Heat the iron to a dull red heat, not quite red hot, as the solder would otherwise be destroyed. Then quickly file the four faces of the point to remove any dirt or oxide that may have got on it and which would prevent the solder from sticking to the bit. Next dip the bit for a second or two in the soldering fluid and melt off a drop of solder on to the piece of sheet tin on which is put a little piece of resin. Turn the point of the bit round and round in the melted solder until it is completely coated. It is very important that the soldering iron should at no time be overheated, as this tinning would be burnt off; nor can it be repeated too often that the surfaces to be joined must be thoroughly cleaned; failure to do this is in most cases the cause of unsuccessful soldering.

To solder handle A to B (Fig. 514). Thoroughly clean that part of B to which A is to be fastened, and handle A, rubbing the edges of A with emery-cloth. Place A on B and rub a little flux with a brush along the join. Dip the bit into the flux and drop a spot or two of solder on the edges by applying the heated iron to the end of the strip of solder. Apply the bit to the solder and trail the solder with the point of the hot iron round the join so that it is filled up.

A little practice will soon enable this to be done successfully, and the skill thus acquired makes the following toy possible.

=A Steamer with a Screw Propeller.= Fig. 515 shows the size and shape of the steamer. It should be about 4 inches wide amidships, 3-1/2 inches deep, and hollowed out as thin as possible, according to directions given in Chapter XIV. Fig. 516 shows the measurements for the stern. The bows should be sharp.

This boat must be fairly large to take the tube which runs through it. Fasten a strip of lead 1/8 inch thick to the bottom of the keel. Paint the boat a suitable colour. When it is dry place it in the water and mark on the stern-post, A B (Fig. 516), the height to which the water comes, for the propeller must come just below this. Midway between this point and the end of the keel bore a hole, C, in the stern-post, through the boat in the direction of the top of the bow. This hole should be 3/8 inch wide and can be made with a red-hot wire.

A brass tube must now be bought from a gasfitter's, 3/8 inch

Now get a piece of stout copper wire (about 1/16 inch thick), D in Fig. 524, and bend it as in diagram. The best way to effect this bend is first to make a sort of elongated =U=, as in Fig. 528; this can be done with pincers. Then put part A in a vice and bend B C and D E out at right angles. Cut it the right length so that the bend will come on a level with the shoeblack's brush and one end will come above post, A. The wire, D, should be pointed or well smoothed with a file at the lower end, so that it will turn easily on a piece of glass glued to the base.

Wire D is supported by two wire hoops or screw-eyes placed in post A. The holes through which it passes must not be too large or it will wobble and not turn smoothly. Now all the parts are ready for putting together. Glue the shoeblack on first, then opposite to him the man. See that the brush passes over the shoe. If for any reason this does not happen, a larger brush can be cut from wood or cardboard and pasted over the shoeblack's hand. Now fasten post A behind the man so that the bend of the wire, D, will be in the right position; pass wire, D, through the wire loops or hooks (these are best made of copper wire); glue the top of it into the hole in the propeller. Glue a piece of glass, E, under the other end. Connect by a thin piece of wire the shoeblack's brush with bend in D. The figure will now work well in the wind.

The shoeblack is the toy one most often sees worked in this way. A man sawing wood is another favourite model, and can be made in exactly the same way.

Two knights fighting can also be made; this involves, however, two propellers.

=Toys worked by Convection Currents.= These are less interesting toys because they do not admit of much variety. The toy is worked over a gas burner, where it acts as a ceiling protector. As the power available from convection currents is very slight, every care must be taken that the figure will work smoothly.

As the toy is exposed to heat, the soldering must be well done. Fig. 529 shows how the toy is made.

The little sailor is cut out of sheet metal (tinned plate); his limbs are fixed by means of rivets or eyelets (the latter are obtainable at a boot repairer's). Take care that they move freely. They will do so if the holes are very smooth. The wire used is steel wire about 1/16 inch; this is fairly easy to bend.

Wire A B is bent as already described in the shoeblack. It passes through loops in the wire at A and D. It is kept from slipping through at A by a ring of wire soldered on the top.

The propeller at B is simply a tin disc with radial cuts, each sector being twisted at an angle by a pair of pliers. The propeller is held by a turn in the wire and by a touch of solder. Notice that the feet of the figure are turned round the wire on which it stands. They can be soldered for greater security. The hand is also curled round the crank pin, but it must be free to turn on it.

The wire framework, E, is soldered to a circle of tin, C, which fits on the top of the lamp. As the figure has to be small it should be as long as possible.

A pair of scissors should be kept for cutting tin, or tinman's snips can be used; cutting pliers and centre punches will also be needed. Holes, however, can be punched in tin with strong round nails and a hammer. Round files are needed for making holes smooth.

Empty tin canisters form a supply of tin plate.

Adjustable cycle spanners are useful for bending wire at right angles; a hide mallet is a great convenience.

Before making a toy like one of those described it is well to practise bending wire with vice, hammer and mallet.

In the last toy, if tinned plate and tinned steel wire are used, the soldering is a fairly easy matter, because the tinning has already been done.