Part 5
Rocket cases, from the smallest to four or six pound, are generally made of the strongest sort of cartridge paper, and rolled dry; but the large sort are made of pasted paste-board. As it is very difficult to roll the ends of the cases quite even, the best way will be to keep a pattern of the paper for the different sorts of cases, which pattern should be somewhat longer than the case it is designed for, and on it marked the number of sheets required, which will prevent any paper being cut to waste: having cut your papers of a proper size, and the last sheet for each case with a slope at one end, so that when the cases are rolled it may form a spiral line round the outside, and that this slope may always be the same, let the pattern be so cut for a guide: before you begin to roll, fold down one end of the first sheet, so far that the fold will go two or three times round the former; then, on the double edge, lay the former with its handle off the table, and when you have rolled on the paper, within two or three turns, lay, on that part which is loose, the next sheet, and roll it all on.
Having thus done, you must have a smooth board, about twenty inches long, and equal in breadth to the length of the case; in the middle of this board must be a handle placed length-ways; under this board lay your case, and let one end of the board lay on the table; then press hard on it, and push it forwards, which will roll the paper very tight; do this three or four times before you roll on any more paper: this must be repeated every other sheet of paper, till the case is thick enough; but if the rolling board be drawn backwards, it will loosen the paper: you are to observe, when you roll on the last sheet, that the point of the slope be placed at the small end of the roller. Having rolled your case to fit the mould, push in the small end of the former F, about one diameter from the end of the case, and put in the end piece within a little distance of the former; then give the pinching cord one turn round the case, between the former and the end piece; at first pull easy, and keep moving the case, which will make the neck smooth, and without large wrinkles; when the cases are hard to choak, let each sheet of paper (except the first and last in that part where the neck is formed) be a little moistened with water: immediately after you have struck the concave stroke, bind the neck of the case round with small twine, which must not be tied in a knot, but fastened with two or three hitches.
Having thus pinched and tied the case so as not to give way, put it into the mould without it’s foot, and, with a mallet, drive the former hard on the end piece, which will force the neck close and smooth; this being done, cut the case to its proper length, allowing from the neck to the edge of the mouth half a diameter, which is equal to the height of the nipple; then take out the former, and drive the case over the piercer with the long rammer, and the vent will be of a proper size. Wheel cases must be drove on a nipple with a points in order to close the neck, and make the vent of the size required; which, in most cases, is generally one fourth of their interior diameter: as it is very often difficult, when the cases are rolled, to draw the roller out, you may make a hole through the handle, and put in it a small iron pin, by which you may easily turn the former round, and pull it out. Fig. 17. shews the method of pinching cases; P a treddle, which, when pressed hard with the foot, will draw the cord tight, and force the neck as close as you please; Q a small wheel or pully, with a groove round it for the cord to run in.
Cases are commonly rolled wet, for wheels and fixed pieces; and when they are required to contain a great length of charge, the method of making those sort of cases is as follows: Your paper must be cut as usual, only the last sheet must not be cut with a slope; having your paper ready, paste each sheet on one side, then fold down the first sheet as before directed, but be careful that the paste does not touch the upper part of the fold, for if the roller be wetted, it will tear the paper in drawing it out: in pasting the last sheet, observe not to wet the last turn or two in that part where it is to be pinched, for if that part be damp, the pinching cord will stick to it, and tear the paper; therefore, when you choak those cases; roll a bit of dry paper once round the case, before you put on the pinching cord; but this bit of paper must be taken off after the case is choaked. The rolling board, and all other methods, according to the former directions for the rolling and pinching of cases, must be used to these as well as all other cases.
To make Tourbillon Cases.
Those sorts of cases are generally made about eight diameters long, but if very large, seven diameters will be sufficient: tourbillons will answer very well from four ounces to two pound, but when larger there is no certainty. The cases are best rolled wet with paste, and the last sheet must have a streight edge, so that the case may be all of a thickness: when you have rolled your cases, after the manner of wheel cases, pinch them at one end quite close; then, with the rammer, drive the ends down flat, and afterwards ram in about one third of a diameter of dryed clay. The diameter of the former for these cases must be the same as for sky rockets.
N. B. Tourbillons are to be rammed in moulds without a nipple, or in a mould without its foot.
To make Balóón Cases, or Paper Shells.
First you must have an oval former turned of smooth wood; then paste a quantity of brown or cartridge paper, and let it lay till the paste has quite soaked through; this done, rub the former with soap or grease, to prevent the paper from sticking to it; then lay the paper on in small slips, till you have made it one third of the thickness of the shell intended; having thus done, set it to dry, and when dry, cut it round the middle, and the two halves will easily come off; but observe, when you cut, to leave about one inch not cut, which will make the halves join much better than if quite separated; when you have some ready to join, place the halves even together, and paste a slip of paper round the opening to hold them together, and let that dry; then lay on paper all over as before, every where equal, excepting that end which goes downwards in the mortar, which may be a little thicker than the rest; for that part which receives the blow from the powder in the chamber of the mortar consequently requires the greatest strength: when the shell is thoroughly dry, burn a round vent at top, with square iron, large enough for the fuze: this method will do for balóóns from four inches two fifths, to eight inches diameter; but if they are larger, or required to be thrown a great height, let the first shell be turn’d of elm, instead of being made of paper.
For a ballóón of four inches two fifths, let the former be three inches one eighth diameter, and five inches and a half long. For a ballóón of five inches and a half, the diameter of the former must be four inches, and eight inches long. For a ballóón of eight inches, let the diameter of the former be five inches and fifteen sixteenths, and eleven inches seven eighths long. For a ten inch ballóón, let the former be seven inches three sixteenths diameter, and fourteen inches and a quarter long. The thickness of a shell for a ballóón of four inches two fifths, must be half an inch. For a ballóón of five inches and a half, let the thickness of the paper be five eighths of an inch. For an eight inch ballóón seven eighths of an inch. And for a ten inch ballóón, let the shell be one inch and one eighth thick.
Shells that are designed for stars only, may be made quite round, and the thinner they are at the opening the better; for if they are too strong, the stars are apt to break at the bursting of the shell: when you are making the shell, make use of a pair of calibers, or a round gauge, so that you may not lay the paper thicker in one place than another; and also to know when the shell is of a proper thickness; ballóóns must always be made to go easy into the mortars.
Of the Method of mixing Compositions.
The performance of the principal part of fireworks depends much on the compositions being well mixed; therefore great care ought to be taken in this part of the work, particularly in the compositions for sky rockets. When you have four or five pounds of ingredients to mix, which is a sufficient quantity at a time (for a larger proportion will not do so well), first put the different ingredients together, then work them about with your hands, till you think they are pretty well incorporated; after which put them into a lawn sieve with a receiver and top to it; and if, after it is sifted, any remains that will not pass through the sieve, grind it again till fine enough; and if it be twice sifted it will not be amiss; but the compositions for wheels and common works are not so material, nor need not be so fine. But in all fixed works, from which the fire is to play regular, the ingredients must be very fine, and great care taken in mixing them well together; and observe that, in all compositions wherein are steel or iron filings, the hands must not touch, nor will any works, which have iron or steel in their charge, keep long in damp weather, without being properly prepared, according to the directions given in the following article.
How to preserve Steel or Iron Filings.
It sometimes may happen, that fireworks may be required to be kept a long time, or sent abroad; neither of which could be done with brilliant fires, if made with filings unprepared; for this reason, that the saltpetre being of a damp nature, it causes the iron to rust, the consequence of which is, that when the works are fired, there will appear but very few brilliant sparks, but instead of them a number of red and drossy sparks, and besides, the charge will be so much weakened, that if this should happen to wheels, the fire will hardly be strong enough to force them round: but to prevent such accidents, prepare your filings after the following manner.
Melt in a glazed earthen pan some brimstone over a slow fire, and when melted throw in some filings; which keep stirring about till they are covered with brimstone, this you must do while it is on the fire; then take it off, and stirr it very quick till cold, when you must roll it on a board with a wooden roller, till you have broke it as fine as corn powder; after which sift from it as much of the brimstone as you can. There is another method of preparing filings, so as to keep two or three months in winter; this may be done by rubbing them between the strongest sort of brown paper, which before has been moistened with linseed oil.
N. B. If the brimstone should take fire, you may put it out, by covering the pan close at top: it is not of much signification what quantity of brimstone you use, so that there is enough to give each grain of iron a coat, but as much as will cover the bottom of a pan, of about one foot diameter, will do for five or six pound of filings: cast iron for gerbes may be preserved by the above method.
The Method of Driving or Ramming Sky Rockets, &c.
Rockets which are drove over a piercer must not have so much composition put in them at a time, as when drove solid, for the piercer, taking up great part of the bore of the case, would cause the rammer to rise too high: so that the pressure of it would not be so great on the composition, nor would it be drove every where equal: to prevent which, observe the following rule; that for those rockets, that are rammed over a piercer, let the ladle[5] hold as much composition as when drove, will raise the drift one half the interior diameter of the case, and for those drove solid to contain as much as will raise it half the exterior diameter of the case: ladles are generally made to go easy in the case, and the length of the scoop about one and a half of its own diameter.
The charge of rockets must always be drove one diameter above the piercer, and on it must be rammed one third of a diameter of clay, through the middle of which bore a small hole to the composition, in order that, when the charge is burnt to the top, it may communicate its fire, through the hole, to the stars in the head: great care must always be taken, to strike with the mallet, and with an equal force, the same number of strokes to each ladle-ful of charge; otherwise the rockets will not rise with an uniform motion, nor will the composition burn equal and regular; for which reason they cannot carry a proper tail, for it will break before the rocket has got half way up; instead of reaching from the ground to the top, where the rocket breaks and disperses the stars, rains, or whatever is contained in the head. When you are ramming, keep the drift constantly turning or moving; and when you use the hollow rammers, knock out of them the composition now and then, or the piercer will split them: to a rocket of four ounces, give to each ladle-ful of charge sixteen strokes: to a rocket of eight ounces twenty-one strokes: to a rocket of one pound, twenty eight: to a two pounder, thirty-six: to a four pounder forty-two: and to a six pounder fifty strokes; but rockets of a larger sort cannot be drove well by hand, but must be rammed with a machine made in the same manner as those for driving piles, which are so very common to be seen, that I shall here omit giving a description of them.
The method of ramming of wheel cases, or any other sort, in which the charge is drove solid, is much the same as sky rockets; for the same proportion may be observed in the ladle, and the same number of strokes given, according to their diameters, all cases being distinguished by their diameters; in this manner, a case whose bore is equal to a rocket of four ounces is called a four ounce case, and that which is equal to an eight ounce rocket an eight ounce case, and so on, according to the different rockets.
Having taught the method of ramming cases in moulds; we shall here say something concerning those filled without moulds, which method, for strong pasted cases, will do extremely well, and save the expence of making so many moulds. The reader must here observe, when he fills any sort of cases, to place the mould on a perpendicular block of wood, and not on any place that is hollow, for we have found by experience, that when cases were rammed on driving benches, which were formerly used, the works frequently miscarried, on account of the hollow resistance of the benches, which often jarred and loosened the charge in the cases; but this accident has never happened since the driving blocks[6] have been used.
When cases are to be filled without moulds, proceed thus; have some nipples made of brass or iron, of several sorts and sizes, in proportion to the cases, and to screw or six in the top of the driving block; when you have fixed in a nipple, make, at about one inch and a half from it, a square hole in the block, six inches deep and one inch diameter; then have a piece of wood, six inches longer than the case intended to be filled and two inches square; on one side of it cut a groove almost the length of the case, whose breadth and depth must be sufficient to cover near half the case; then cut the other end to fit the hole in the block, but take care to cut it so that the groove may be of a proper distance from the nipple: this half mould being made and fixed tight in the block, cut, in another piece of wood nearly of the same length as the case, a groove of the same dimensions as that in the fixed piece; then put the case on the nipple, and with a cord tie it and the two half moulds together, and your case will be ready for filling.
The dimensions of the above described half moulds, are proportionable for cases of eight ounces; but notice must be taken, that they differ in size in proportion to the cases.
Note, the clay, mentioned in this article, must be prepared after this manner; get some clay, in which there is no stones nor sand, and bake it in an oven till quite dry; then take it out and beat it to a powder, and afterwards sift it through a common hair sieve, and it will be fit for use.
Of the Proportion of Mallets.
The best wood for mallets is dry beech, though some have preferred other sorts of woods and have likewise pretended to determine their exact weight, which is not of much signification; however, for the better instruction of those who have not made a great progress in this art, I shall here give a good proportion for mallets; but at the same time would have every practitioner know, that if he makes use of a common mallet, of a moderate size, in proportion to the rocket, according to his judgment, and if that rocket succeeds, he may depend on the rest, by using the same mallet; yet it will be necessary that cases of different sorts be drove with mallets of different sizes.
The following proportion of the mallets for rockets of any size, from one ounce to six pound, may be observed; but as rockets are seldon made less than one ounce, or larger than six pound, I shall leave the management of them to the curious; but all cases under one ounce, may be rammed with an ounce rocket mallet. Your mallets will strike more solid, by having their handles turned out of the same piece as the head, and made in a cylindrical form: let their dimensions be worked by the diameters of the rockets: for example; let the thickness of the head be three diameters, and its length four, and the length of the handle five diameters, whose thickness must be in proportion to the hand.
Of the Proportion of Sky Rockets, with the Manner of heading them.
Fig. 13. represents a rocket compleat without its stick, whose length from the neck is five diameters one sixth; the cases should always be cut to this length, after they are filled: M the head, which is two diameters high, and one diameter one sixth and a half in breadth; N the cone or cap, whose perpendicular height must be one diameter one third. Fig. 14. is the collar to which the head is fixed; this is turned out of deal or any light wood, and its exterior diameter must be equal to the interior diameter of the head; one sixth will be sufficient for its thickness, and round the outside edge must be a groove; the interior diameter of the collar must not be quite so wide as the exterior diameter of the rocket; when this is to be glued on the rocket, you must cut two or three rounds of paper off the case, which will make a shoulder for it to rest upon. Fig. 15, a former for the head; two or three rounds of paper well pasted will be enough for the head, which, when rolled, put the collar on that part of the former marked O, which must fit the inside of it; then with the pinching cord, pinch the bottom of the head into the groove, and tie it with small twine. Fig. 16, represents a former for the cone. To make the caps, cut your paper in round pieces, equal in diameter to twice the length of the cone you intend to make; which pieces being cut into halves, will make two caps each, without wasting any paper; having formed the caps, paste over each of them a thin white paper, which must be a little longer than the cone, so as to project about half an inch below the bottom; this projection of paper, being notch’d and pasted, serves to fasten the cap to the head.
When you load the heads of your rockets with stars, rains, serpents, crackers, scroles, or any thing else, according to your fancy; remember always to put one ladle-ful of meal powder, into each head, which will be enough to burst the head, and disperse the stars or whatever is contained therein: when the heads are loaded with any sort of cases, let their mouths be placed downwards; and after the heads are filled, paste on the top of them a piece of paper, before you put on the caps. As the size of stars often differ, it would be needless to give an exact number for each rocket, but this rule may be observed, that the heads may be nearly filled with whatever they are loaded.
Of the Decorations for Sky Rockets.
Sky rockets bearing the pre-eminence of all fireworks, it will not be improper to treat of their various kinds of decorations which are directed according to fancy; some are headed with stars of different sorts, such as tailed stars, brilliant stars, white stars, blue and yellow stars, &c. some with gold and silver rain; others with serpents, crackers, fire-scroles, marrons; and some with small rockets, and many other devices, as the maker pleases.
Dimensions and Poise of Rocket Sticks.
Weight | Length of |Thickness|Breadth |Square at| Poize from of the |the stick. | at top. | at top.| bottom. |the point of rocket.| | | | | the cone. -------+-----------+---------+--------+---------+------------- lb. oz.| ft. in. | Inches. | Inches.| Inch. | ft. in. -------+-----------+---------+--------+---------+------------- 6 0 | 14 0 | 1·5 | 1·85 | 0·75 | 4 1·5 4 0 | 12 10 | 1·25 | 1·40 | 0·625 | 3 9· 2 0 | 9 4 | 1·125 | 1· | 0·525 | 2 9· 1 0 | 8 2 | 0·725 | 0·80 | 0·375 | 2 1· 8 | 6 6 | 0·5 | 0·70 | 0·25 | 1 10·5 4 | 5 3 | 0·3750 | 0·55 | 0·35 | 1 8·5 2 | 4 1 | 0·3 | 0·45 | 0·15 | 1 3· 1 | 3 6 | 0·25 | 0·35 | 0·10 | 11 0· ½ | 2 4 | 0·125 | 0·20 | 0·16 | 8 0· ¼ | 1 10½ | 0·1 | 0·15 | 0·5 | 5 0·5
The last column on the right in the above table, expresses the distance from the top of the cone, where the stick, when tied on, should ballance the rocket, so as to stand in an equilibrium on one’s finger or the edge of a knife. The best wood for the sticks is dry deal, made after the following manner; when you have cut and planed the sticks according to the dimensions given in the table, cut on one of the flat sides at top, a groove the length of the rocket, and as broad as the stick will allow; then on the opposite flat side, cut two notches for the cord, which ties on the rocket, to lay in; one of these notches must be near the top of the stick, and the other facing the neck of the rockets; the distance between these notches may easily be known, for the top of the stick should always touch the head of the rocket. When your rockets and sticks are ready, lay the rockets in the grooves in the sticks and tie them on. Those who, merely for curiosity, may chose to make rockets of different sizes, to what I have expressed in the table of dimensions, may find the length of their sticks, by making them for rockets, from half an ounce to one pounds sixty diameters of the rocket long; and for rockets above one pound, fifty or fifty-two diameters will be a good length; their thickness at top may be about half a diameter, and their breadth a very little more; their square at bottom is generally equal to half the thickness at top. But, although the dimensions of the sticks be very nicely observed, you must depend only on their ballance: for, without a proper counterpoise, your rockets, instead of mounting perpendicularly, will take an oblique direction, and fall to the ground before they are burnt out.
The Method of Boring Rockets which have been drove solid.