Polyvinylchloride/Hexachlorobenzene
75
60
50
80
50
4
25
240
20
1
30
50
20
5 2 3 1 1 1 112
60
23
5 6 3 160
60
6
50
50
50
2 150
50
40
50
40
1 1By no means a comprehensive listing, this matrix sketches the violent nucleus of powders commonly used to make salutes. First rule: ALL FORMULAE THAT CONTAIN POTASSIUM CHLORATE SHOULD BE CONSIDERED SUICIDAL. DO NOT MIX THEM. Simplest, safest mix for small salutes contains potassium perchlorate and dark or Black German aluminum. Oddly, this mix loses some of its punch in bulk, say, that needed for a 3" aerial bomb. In that case, addition of sulfur or antimony sulfide-gas formers- restores body to the blast, and allows use of the safer bright aluminum. Formulas that contain only nitrate oxidizers suit only extremely strong cases, since they lack the kick to detonate. Formulas 16 and 18 are examples of powders fancied to give colored flash reports. Most of these mixes have been quoted in other texts; a few represent minor variations on otherwise standard formulas. Clearly, many of these chemicals are poisonous, and demand precautions in addition to those applied to flammable mixtures. Related only for informational purposes. Get an explosives license and proper training if you would mingle in this forbidden realm ....
Sealing the upward end worked in reverse. The operator poured rice hulls in on top of the flash powder, followed by more liquid adhesive on the hulls.
It takes less than 15 minutes for this type of cement to solidify to the point that the tubes can be plucked from the mold and put aside to dry fully while the next batch comes through.
Some felt the rice chaff served a dual purpose in that, as the salute was handled, it dispersed through the powder and prevented caking. Since the loudest reports were believed to result from loose powder, this was desirable.
At this point in manufacture we had closed paper tubes filled with flash powder. It was time for fusing. We can see working backward into the process, why fuses came to be placed in the center of the casing instead of the ends, as was the case with firecrackers. Putting a fuse through the end closures of granite-like adhesive would have proven impossible without a carbide-tipped drill, and would have wasted time.
The most practical route lay through the soft paper of the casing. An awl, or just a nail (a dull from the look of samples the author bought late in 1969) was used to punch a hole into the casing, and the fuse was inserted.
The cheapest way turned out also to be best from a theoretical/intuitive standpoint. Center placement of the fuse started the powder burning outward in two directions at once, rather than from end to as would have happened with an end-placed fuse.
Left in that state, with nothing but friction to hold the fuse, flash powder would leak, and the fuse would fall out with minimal handling. This led to the practice of priming, which, again, served dual ends. The end of a 1-1/2" length of 1/8" green fuse was dipped in priming, then stuffed into the hole in the case, and the assembly set aside to dry. Look at the old photo of a silver salute purchased at the fabled open-air market in November, 1969, for the then-outrageous price of ten cents. The black ring at the base of the fuse is priming.
They called it priming because it took fire far more easily than flash powder, and made for fewer duds. But here again, the pluses of priming proved flawed in a way that, perhaps more than any other aspect of tube salutes themselves, led to the real notion that these engines held danger.
To serve its dual purpose of securing the fuse and promoting ignition of the flash powder, the priming came to be exposed on the surface of the casing, which meant that a stray spark from any source-sparks thrown off by the fuse as it was lit, for example-could set the device off instantly, and sometimes did. Priming was used on both cherry bombs and tube salutes. We see it sti lion Oriental "cherry smoke balls."
From time to time we come across entrepreneurs who step up to the old cannon-cracker class of salutes, with inside diameters exceeding 3/4" and lengths of three to five inches, with fuses poking out about four inches, a good safety measure for a naturally unstable unit. These bombs surface in country-store type places, and the right code words may put you onto a source from a class C stand in some venues. The old- boy network helps, just Iike the street drug gig, such a sad testament, since the last thing these entrepreneurs want is to cause personal or property damage.
TUBE SALUTES IN THE MODERN ERA
Thus it was in the old days, and modern pyros, despite the fact that they dealt with banned devices, were quick to spot the hazards. The initial remedy took the form of all-paper construction. Instead of silicate- based adhesive, they sealed the ends with paper caps. That eliminated the showers of granite-like shrapnel. Second, though some purists sti II primed the fuses, they dipped one tip of the fuse in priming, let it dry, then inserted the fuse through the interior of the casing, leaving all of the primed part inside, and secured the fuse in place with standard white glue. This left the outside tip of the fuse as the only exposed, flammable surface, and made the device Iiterally immune to ignition from stray sparks, except one hitting the end of the fuse.
If the purpose of tube salutes in the first place was to make a bigger bang than firecrackers, at least the new wave of pyro wanted to have complete control of when the device would detonate. Formulas based on potassium chlorate certainly gave more bang per unit weight, but left us with that uneasy feeling that the stash in the garage might not wait until the Fourth to kick off. Chlorate-based blends, volatile ones like flash powders, had a way of detonating spontaneously. To some stalwart souls that meant simply adding magnesium carbonate or barium carbonate to the mix and hoping for the best. But to the genuinely safety-conscious it meant turning to another source of oxygen, potassium perchlorate.
-which, truth told, was not bad. The perchlorate proved itself plenty potent as long as we paid attention to details: particle size and mixing. We understand already that reaction rates increase with surface area. Potassium perchlorate supplied was usually powdered finely enough, about 200 mesh. But many pyros took to grinding it into flour-like dust using a mortar and pestle. Some upmarket hobbyists resorted to ball mills made from rock polishers and loaded with special hard/dense lead alloy spheres that yielded incredibly fine powder.
While this helped, it reached the point of diminishing return rapidly. POWdering for five minutes in a mortar gave no better performance than letting the stuff go for days in a motorized mill. The limiting factor turned out to be the particle size of the fuel. For flash mixes, that meant aluminum. The fearsome tale of Black German Pyro aluminum has been told.
SYMPATHETIC DETONATION
From time to time we heard tell of explosions of entire boxes of cherry bombs or M-80s, often in the back seat of souped-up cars driven at top speed by callow youths who terrorized neighborhoods by tossing the deadly units out the window. (What a better time it was, too, when that lewd delinquency was all the terrorism we knew •••• )
The point at issue is, Why and how could a box of overgrown firecrackers explode all at once? Didn't you have to light the fuse to set one off? After all, it wasn't as if the boys were carrying dynamite or plastique.
Analyze the physics of it in Iight of what you already know of salutes. Caching tens of them in even a fl imsy box produces confinement. The explosion of one adds much more by its pressure wave. That wave is strong enough to rupture one or more other casings, letting the wave impinge unblunted on the next powder charge, and the next, all of it in a split second. One modest boomer blossoms into the equivalent of a 3" aerial salute popping in the car. That's enough to blowout the bottom chassis, the windows, and the youths' eardrums, a fitting punishment for young reprobates.
The lesson of it is, never stock completed devices in quantity. Their proximity and the laws of physics create an extreme hazard. The laws against possession (that number would probably qualify you for the added charge of "with intent to distribute") prohibit it altogether. Just for information.
CHERRY BOMBS
The manufacture of cherry bombs, M-80s, and silver salutes grew up as a cottage industry in back rooms and basements in parts of Ohio and Pennsylvania, lately of Cal ifornia, simply because these devices are so easy and relatively safe to make, and always because as banned items, they bring a sagging bag of cash.
First, they are federally verboten, meaning that it's illegal to make, use, sell, transport, or think about them. They probably should be banned because of what mutants, cretins, and other low-Iifes found in large cities do with them. Country folk use cherry bombs for harmless pranks, such as blowing up mailboxes. But in cities, they get dipped in glue, then rolled in BBs to make tiny grenades for gang fights between fourth-graders. In one city, a "fan" threw a cherry bomb at a professional baseball player. It detonated close to his head. The blast knocked him cold. Had he been looking the wrong way it could have blinded him. Harmless fun.
But what irresponsible, depraved, and sinister urge would prompt a surveillance writer to reveal the secrets of these dread devices? Paradoxically, a concern with safety. The author lived his basement-bomber days in the 1960s, when you could order cherry bombs by mail, along with the chemicals and casings to make them. (In fact, you could order them as late as 1968 from at least one company that advertised in Popular Science,
on the strength of a signature from an unspecified local official •••• ) The author went on to a degree in chemistry-none of the knowledge ever applied to explosives and propellants-perhaps reflecting his concern with safety. Knowledge of how accidents involving these fascinating devices happened provoked him to write this, both to explain how they work and to warn those who buy them of their hazards.
Companies catering to the pyro hobby used to sell pairs of what were called cherry bomb cups. These manila-colored paper hemispheres consisted of a smaller and a larger cup, one to fit inside the other. The method of manufacture suggested by one vendor was to pierce the center of the larger cup, glue a good length of green fuse in it, prime the interior segment of fuse if desired. Next, fill the smaller cup with flash powder, then place the larger cup over it. Secure the two with a dab of glue or paste.
Next, dipping: To get that red, rock-like outer shell, the hallmark of a cherry salute, the completed devices had to be immersed in a mix of fine sawdust, red coloring (powdered tempera paint served), syrupy sodium Silicate, and calcium carbonate. The consistency of the dip had to be adjusted such that a solid, even shell of 3/32" to 1/8" thickness would adhere to the cups, and not sag to the bottom as the finished product was held by clothespins on its fuse while it dried.
Some early literature commended chlorate-based compositions, but with all the moisture likely to seep into the case that course seems insane.
This amateur method never produced quite the same product one found sold at roadside stands. It lacked that professionally made look and feel of the real thing. One gets the impression that commercially sold cherry bombs were made by the barrel technique described in Davis' The Chemistry of Powder and Explosives, in the same manner outlined for manufacture of torpedoes, and which is used also to make spherical stars for Oriental fireworks (the pharmaceutical industry uses it, too, to make pills, even the good kind •••• ).
In this case, the two cups would be assembled, sans fuse; dumped in masses of hundreds into a rotating bin, into which a dilute solution of sodium silicate would be poured or sprayed, along with dashes of calcium carbonate, red dye, and fine sawdust. The rolling action accreted an extremely even, smooth layer distinct from that of the dip method. As to how the fuse holes were made, we can only speculate. One cannot imagine a sane person drilling into the device, since that is practically an invitation for detonation from friction. Yet commercially sold cherry bombs the author saw in the early sixties always wore priming around the fuse, on the outside, meaning that insertion of the primed fuse had to be the final step in manufacture.
Cherry bombs: What an irresistible blend of charm and danger. Sold in boxes of half a gross, the last one the author saw be ing about 1962, and bearing a price tag of something like $4. But what a premium they command today, so much so that organized crime is rumored to have a hand in distribution.
CHERRY BOMBS & SAFETY
Cherry bombs suffer a safety record, or the lack of one, worse than that of tube salutes. The reason lies with their construction. It makes them tiny fragmentation grenades, along with the risk of unpredictable ignition due to exposed priming.
Upon detonation, their tough outer shell fragments into an expanding sphere of eye-piercing shrapnel, just like a grenade. Some years back, the papers reported a genuinely tragic tale of a man who lost sight in both eyes when the cherry bomb he was lighting exploded. The story told that he believed that he was being careful. He was not holding the device, thank goodness, and sought to light it at arms' length with a sparkler.
Needless to say, the shower of burning iron from the sparkler hit the exposed priming before it lit the fuse, and the unit exploded mi IIiseconds later.
Exposed priming, fragments produced by explosion, and a fair degree of power. These three factors explain why cherry bombs and tube salutes are, and probably should be, banned.
A corollary holds that those who wish to take risks and survive a mishap with 20/20 vision and all their fingers MUST assume that premature detonation will happen, and don safety gear to eliminate risk of injury when it does.
198
Never handle salutes except with tongs, or if you must use your hands, wear thick leather work gloves and grip the fuse, not the body of the unit. Second, do not approach finished salutes unless you are wearing goggles, preferably polycarbonate, the kind that resist the impact of bird-shot fired at point-blank range. Full-face protection of similar stoutness couldn't hurt. Third, your ears can do without a 150-decibel blast two feet away. Wear hearing protectors. Fourth, never let multiple small explosive devices accumulate. If one goes, they all go, instantly.
THE LEGEND OF THE PLASTIC CHERRY BOMB
Some years back, the sixties it now seems, there were said to have been sold cherry bombs-black market of course, and of limited distribution-that differed from the standard type in having a red plastic case, probably cheap polystyrene. In addition, they were so much more powerful than common cherry bombs as to question whether they contained high explosive, such as the military staples, C3 and C4, perhaps more freely obtained back during the Vietnam era. One source reported that, where the ordinary cherry bomb did nothing to his concrete driveway, a plastic cherry took a fist-sized divot out of the rock and sent shock waves booming across suburbia like a flight of F4s scorching the treetops with their afterburners.
Careful reading of texts that deal with the effects of explosives tells us that detonation of several ounces of, say, mercury fulminate, a high explosive used in blasting caps (blasting caps initiate detonation of other high explosives, such as the now-outmoded dynamite, as well as military plastic explosives) fails to do more than minor local damage, despite a fearsome report. That calls up a speculative reconstruction of the plastic cherry bomb as shown in the diagram, one that would explain its ability to dent concrete. C4 has become harder to come by, what with cessation of the Vietnam conflict, and plastic explosive coming over from the other side of the iron curtain has been earmarked for more politically specialized use. Perhaps that explains the disappearance of the fabled plastic cherry bomb••••
"PROFESSIONAL PYROTECHNIC ADHESIVE"
Pyros paid a dollar each to learn the formula back in the early seventies. Two versions have been reported. The least expensive and easiest to make-the choice of pros for those reasons-was nothing more than finely powdered calcium carbonate (chalk) mixed with a syrupy solution of sodium si Iicate. Those who owned chemistry sets purchased prior to 1964 will recall sodium silicate solution as "water glass," used to paint eggs in one fondly recalled exercise. But that solution was far too dilute for use in an adhesive/end-plug. No, it must be of a concentration to give it the consistency of Kayro syrup. (The figure that comes to mind is 42.2 Baume', but that may be the author's memory playing sinister tricks .... ) Mixed with calcium carbonate, it forms a thick, sticky mass that dries rapidly to concrete-like hardness. (Do not stir it with any tool you plan to re-use. Once hardened, and submersion in water does not prevent hardening, the stuff is all but impossible to chisel off.)
The second formula, one that, at least in the author's hands, always left unsightly lumps when it hardened, called for the addition of finely powdered zinc oxide in a ratio of 1: 1 by weight to the calcium carbonate. This gave the finished product more of a gloss-white look. Its effect on hardness or tack was not apparent.
The important qualities of PPA were its thick consistency, which let it serve as an effective seal and not run as would conventional white glue; the fact that it maintained its bulk as it dried; and dry quickly it did. It was by its composition alkaline, a balm to chlorate-based powders despite its moisture. Finally, it was strong, literally rock-like in hardness.
This adhesive was a true hero of the tube-salute business. But, like all heroes, it suffered a fatal flaw: its great strength and hardness, which made for so sturdy an end closure, broke into a spray of eye-penetrating