The Pyrotechnist's Treasury Part 3

A variety of rocket fuses will be found in the Tables; the first is as good as any, and will answer for all sizes from 3/8 to 12/8. As a rule, the fiercer fuses, containing meal powder, may be used for small rockets; but are, by no means, necessary.

A rocket, when starting, makes a roar; but this is not on account of the fierceness of the fuse, but of the extent of the surface ignited. Rocket composition, laid in a train, burns very slowly.

ROCKET STARS.

Rocket stars are made in three or four ways. First cut, or chopped, or naked stars. This mode is used for nitre stars only: chlorate of potash stars require different methods. It is a singular circ.u.mstance that, though chlorate of potash stars are much fiercer than nitrate of potash stars, yet the latter light without any trouble, while the former, if made in the same way, would be almost sure to miss.

TO MAKE CUT STARS.

Wet the composition with thin starch, or dextrine solution, or gum water, sufficiently to bind; press it into a flat ma.s.s, on a slate, or Dutch tile, with a knife, or small trowel, till about 3/8 of an inch thick. Indent the surface with the edge of the knife, in parallel lines, about 3/8 of an inch apart, and cross these with equidistant indentations, at right angles. Set the ma.s.s by, to dry gradually. When nearly dry, break it up into little 3/8 cubes, and lay them out, to dry thoroughly. The broken edges will be rough, and will catch easily.

DRY PILL-BOX STARS.

Take a sheet of note paper, and cut it into four equal parts; each part will be about 4-1/2 inches by 3-1/2. Paste and roll them on a (3-1/2)/8 bra.s.s tube, so as to have the cases 4-1/2 inches long. To make these into pill-boxes, perfectly true, like those used by the druggist, they must be cut in the lathe. For this purpose, turn a cylindrical piece of wood, fig. 27, which is to fit easily into the case, except at a, where it is to be turned sloping a little larger, so that when the case is slipped over it, it will bite at the part a; otherwise, on putting the chisel to it, it would slip round, without getting cut. Mark the case, with a black-lead pencil, at every half-inch; suspend it in the lathe; and cut it at the marks. Next procure a 7/16 inch punch, with which to cut out the bottoms. These are to be made of card, or bristol-board. Lay the card on a piece of sheet-lead, or the grain end of a piece of beech, and give it a smart blow or two with a hammer; keep on punching till the punch contains a dozen or more discs, then push them out. When a number are ready, press them into the pill-boxes, with a rammer that fits loosely.

The composition is to be put into these dry, and driven in with a solid rammer, and the little mallet, before described.

This was the original way of making them, but is perfectly unnecessary.

Roll the tubes as directed, of two thicknesses of paper, with a little bit to lap over. Cut them across, with one sharp clip, with a strong pair of scissors. This will slightly flatten them; but they may readily be restored to the cylindrical form, by slipping them on a piece of wood, and rounding them to shape with the fingers. No bottoms need be provided, no punch used.

TO FILL THE BOXES WITH DRY COLOUR.

Rest the box on a flat surface, put in some composition, and drive it in with a bra.s.s or boxwood drift and the little mallet, till half full, as in fig. 28. Then fill up the box with more colour, set a little bit of match upright in the side, and mallet it in, till the box is almost full. The drift for this must be cut flat on one side, to allow for the match. On the top put a very little dry meal powder, or sh.e.l.l-fuse, and press it in with the finger. Cut a piece of double-crown, about an inch broad, and long enough to go rather more than once round the pill-box: paste it all over; lay the pill-box on it, and roll it up; tuck in one end, to make a bottom, and press the other end round the match, and on the meal powder, or sh.e.l.l-fuse, till it a.s.sumes the form of fig. 29.

ANOTHER WAY.

Set the pill-box on a flat surface, put in a very little meal powder or sh.e.l.l-fuse, then some composition, and mallet it in till full. Roll this up in a piece of double-crown as before; tuck in the bottom, and set by to dry; when dry, put into the other end--the end containing the film of meal or sh.e.l.l-fuse--a piece or two of thin match, and tie it in, as in fig. 30. Dry pill-boxes are best for making chameleon stars; these are half one colour and half another. Make a dozen stars, half yellow and half green, and a dozen more half blue and half crimson; put these into a rocket; they will burst green and crimson, and change to blue and yellow.

BOTTOMLESS PILL-BOXES.

The cases are the same as before. To fill them, damp the composition as for Roman candle stars; put a bit of quickmatch into the case, as at fig. 31, and press in the composition. This is usually done with the fingers, but is not very pleasant work, especially with lac solution. A cleaner way, though more tedious, is to fit the case on to a little foot, with a side notch in it, fig. 60; then slightly mallet in the composition. Or a notch may be cut in the side of the box, fig. 61, and the match put in, as fig. 62, and slightly malleted.

Instead of making the cases entirely of writing paper, they may be made half of writing paper and half of coloured double-crown, to indicate the colour of the star.

Another way is to sift a thin layer of French chalk over a sheet of paper, and to roll the stars in it, one by one, as they are punched.

When dry, brush off the superfluous chalk, and prime with a bit of match, tied across the mouth.

ENVELOPED STARS.

Pump and drive the stars exactly as for roman candle stars, They may be (3-1/2)/8 diameter, and 5/8 long; or they may be formed with figs. 1, 2, and 3, and the side pin of fig. 2 may be removed to c, in which case the stars will be 5/8 diameter, and (3-1/2)/8 deep; the former will be an oblong cylinder, the latter an oblate. Cut a strip of red, blue, green, or yellow double-crown, of a suitable breadth, and long enough to go twice round the star. Paste the strip all over, or gum it at the edge only, and lay the star upon it, as at a, fig. 41, with a bit of match behind it; then roll it up and put by to dry. When pasted, it shrinks and holds the match tight; when gummed at the edge this is not always the case; it may then have a piece of thin binding-wire twisted round it. It will have the appearance of fig. 32. In fig. 31, the match is embedded, and dries in the damped composition; in the enveloped stars the stars are dried first, and the match lies outside and blows through.

Enveloped stars show well in the air.

The word envelope, as used in these pages, must not be confounded with the same word as applied to the coverings for letters. It is rather synonymous with the term wrapper; you lay an ounce of tobacco on a piece of paper, roll it up and tuck in the ends. So with cases: you roll them up in a piece of paper, and leave an inch vacant at each end to receive quickmatch, &c. This is termed the envelope, that is, the wrapper.

ROCKET HEADS.

Heads for small rockets may be made of two or three rounds of paper rolled dry, and secured on the inner and outer edges with paste. After sticking it on the case, which it may be made to fit, as in fig. 36, pinch the top in like a choke, only tight, and tie it round with twine or flax. For coloured rocket heads, 6/8 and upwards, the head may be enlarged by fixing a collar round the top of the case. To make the collar for a 6/8, roll a case on a 9/8 former, and when dry cut it into short lengths in the lathe, as recommended for pill-boxes; if unprovided with a lathe, saw it with a fine-toothed saw. The advantage of the enlarged head is, that it brings the stars nearer to the rocket, and prevents it from being top-heavy. Another way is to make the heads tapering, and the tops conical, as in fig. 39. One part is rolled on fig. 34, the other on fig. 35; or, a cone may be made of a circular piece of paper, without a former. Cut the circle, along the radius, to the centre; bend it into a cone; secure the edge with sealing-wax, and paste paper over it to overlap the rim: snip the edge with the scissors; paste it inside, and secure it to the other part. But the quickest way of all is to make a long paper bag, which may be made to fit to the greatest nicety. For this purpose take a tape-measure; or lay down, on the edge of a strip of writing paper, 7 or 8 inches long, and 1 inch broad, 6 inches, divided into eighths, transferred from a foot-rule.

Suppose the 6/8 rocket has a collar, which, on being measured by the paper just alluded to, is found to be 4-2/8 inches round; add to this 3/8 for lapping over, making 4-5/8 inches. Cut a piece of imperial brown 4-5/8 broad, and as long as the case, 6 inches. Make this into a paper bag, 2-1/8 inches broad. Be careful that the corners are perfect; a strip of double-crown may be pasted over them. When dry, pinch the mouth open till cylindrical, and merely allow the stars to drop in without forcing them; this will keep the top edge of a wedge shape, fig. 37, and answer the purpose of a cone. If the paper is thin, the bag must be made of two thicknesses; the paper will, then, require to be 9 inches by 6; 4-3/8 of this will have to be kept dry, and the other 4-5/8 pasted.

A head, made in this way, if required to hold gold rains, or serpents, can instantly be reduced to a cylindrical shape, by pushing the rocket-case right up it, to the top; this will cause the corners to stick out, like two horns; press them down, and secure them with sealing-wax. Attach a cone, if desired.

Heads made like figs. 38 and 39 may be of three thicknesses of paper, pasted all over.

Fig. 39 shows the manner of tying on the sticks. No variation must be made in their lengths, and it is not advisable to alter their size. To adapt it to the wood, however, a slight alteration might be permitted.

For instance, instead of 3/8 square, it might be (2-1/2)/8 by (3-1/2)/8, a slight increase one way, compensated by a slight diminution the other.

It must, however, on no account, be so increased and diminished, as to approach the shape of a lath, as such stick would vibrate, and cause the rocket to quiver. When the heads are a paper bag of the shape of fig.

37, the stick must be tied on, as indicated by the dotted lines.

If the stick is suited to the rocket, it will, when suspended on the finger almost against the mouth, as at f, fig. 40, lie, not quite horizontal, but slightly sloping downward. The wood should be dry pine, free from knots. The sticks are generally cut with a carpenter's cutting-gauge. If the learner has a lathe he will find a 6-inch circular saw convenient for cutting them.

For amateurs, a 6/8 rocket is a good size; large enough, and small enough. If 5/8 and 4/8 are made, two hollow drifts will be sufficient; for 3/8, one hollow drift. Very small rockets, 2/8, are made for children; they are rammed solid, and a hole is pushed up them with a bradawl.

Rockets in former times, before the present days of compet.i.tion, were charged in moulds. These were of gun-metal, bored truly cylindrical, furnished with hinges, to open and admit the case; they were then screwed up, and might be charged as hard as possible. Names were given them according to the bore of the mould, that is, the external diameter of the cases; a 4/8 was termed an ounce rocket; a 5/8, a two ounce; a 6/8 a quarter pound; a (7-1/2)/8 a half pound; a 9/8, a pound; a 12/8, a two pound.

These names were determined by the weight of a leaden ball of the same diameter as the bore. Now a sphere of lead, 7-1/2 inches diameter = 90 lbs., or 1440 ounces; consequently one of 15 inches = 720 lbs., similar solids being to each other as the cubes of their like dimensions: the latter sphere being twice the diameter from top to bottom; twice the diameter from left to right; and twice the diameter from front to back; 2 2 2 = 8.

The external diameter of the rocket being 7-1/2 inches, the internal would be 5 inches, and this would be a 90-pounder: hence, for an inch rocket, we have the proportion,

oz. oz.

5 : 1440 :: 1 : 1152

so that a 12-ounce, or 3-quarter-pound rocket, ought to be a trifle above an inch.

Required the weight of a 6/8 rocket. 5 inches = 40/8.

oz. oz.

40 : 1440 :: 6 : 486

So that a 6/8 is a trifle too large for a quarter-pound.

If, conversely, we require to know the size of a half-pound, or 8-ounce rocket,

oz. oz.

1440 : 40 :: 8 : 3200/9

and ?(3200/9) = ?(9600/27) = (?9600)/3 = 708

So, properly, a half-pounder is a trifle over 7/8. The names in use enable the makers to understand each other, but they are not mathematically correct, and are of no utility to an amateur.

The following table shows the true weight of leaden spheres, the dimensions being taken in inches.