CC:. Subj:.COLORED FLASH, Return-path: id <01H9HNJ9JOC00000MZ@cudnvr.denver.colorado.edu>; Wed, 2 Mar 1994 08:25:56 MDT AA20815; Wed, 2 Mar 94 07:19:03 -0800 Wed, 2 Mar 94 10:15:30 -0500 Date: 02 Mar 1994 10:15:32 -0500 (EST) Subject: COLORED FLASH, Message-id: <9403021515.AA29099@us2rmc.bb.dec.com> X-Envelope-to: rpeacock Content-transfer-encoding: 7BIT Apparently-To: rpeacock@cudnvr.denver.colorado.edu To:.BUDA CC:.PIERSON Subj:.Colored flash, for pyro.dis A few bits on "colored flash" from the files of the New Hampshire Pyrotechnics Association. Briefly, it seems to be more trouble than it's worth, unless there is more development... regards dwp Some thoughts on Colored Flash "Light the Twelve" After reading the November 1992 NHPA Newsletter article on Colored Flash, I'd like to add my 'penny cracker's worth", and shed some colored light on the subject. .["Light the Twelve is a shell buiilder of some note, PGII Competition .shooter and prize winner. Attendees at Convention have seen his work. In short: when he talks, listen up....] I have had some experience in using colored flash, and would like to share some vital information that was not in the original article. As was stated in the Reminder: " Flash is probably the most hazardous of all pyro compounds".(1) Well, folks, colored flash is likely more hazardous. As with any mixture utilizing magnesium powders, there are particular dangers that must be dealt with. First of all, the magnesium that must be used for the flash to be effective is the granular type, of at least 100 mesh. Atomized magnesium will produce a handsome illumination star, but isn't reactive enough to give the flash effect. Thus, the more reactive magnesium is more dangerous to handle. All magnesium powders must be protected in some manner from the corrosive attacks of the oxidizers they are in contact with. According to Takeo Shimizu's article in Pyrotechnica VIII, linseed oil would be most effective in protecting magnesium from all the oxidizers used in published formulas. But, alas, coating magnesium with linseed oil slows the burning speed of the composition to the point of being useless as a flash powder. The next best coating is potassium dichromate, which is only slightly attacked by the oxidizers. Although potassium dichromate is an extremely nasty chemical to work with, it must be used in this application. Instructions for treating the magnesium can be found in Dr Shimizu's article(2). In magnesium star manufacture, which is more common, linseed oil coating and atomized magnesium powder work quite well with all oxidizers except ammonium perchlorate., used in strobe stars. As an added advantage, most mag stars contain a relatively large amount of Parlon (chlorinated rubber) and are bound with acetone, which dissolves the rubber and provides an almost waterproof covering for the magnesium. In flash formulas there is no such protection from moisture. This presents a very real concern, especially with the red and purple formulas, which contain strontium nitrate. The hygroscopicity (tendency to absorb water vapor) of this compound is quite high, leading to problems in areas of high humidity. I can't think of anything much worse than a large salute full of damp magnesium and storing oxidizer, except, maybe, storing that device in MY magazine. I would advise anyone contemplating the use of colored flash to limit it to small salutes, such as lambetti, thunder, cannonades, etc. Actually the effect seems much better in these small devices, as the smoke produced by the burst reflects the light and enhances the color. I would not advise using formulas containing Strontium Nitrate in humid climates, or anywhere that moisture could be introduced inadvertently. It would be best not to store any device containing colored flash for any length of time. The colors produced by the flash formulas are not very strong. Without some standard of reference, they may actually appear white. All in all, in my opinion, the effect is not worth the effort or danger. 1) See also AFN no 124, January, 1992, What About Flash, by Bill Ofca. 2) Pyrotechnica VIII, Studies on Strobe Light Compositions, by Dr Takeo Shimizu. Trivia Time A few items, from Modern Chemical Magic, Lippy & Palmer. "Modern" is a bit misleading... My guess is mid '50s... Colored Flash Powder: Red "powdered" magnesium 2 parts by weight Strontium Nitrate 2 parts by weight Green "powdered" magnesium 2 parts by weight Potassium Nitrate 2 parts by weight Powdered Boric Acid 2 parts by weight Powdered Sulphur 2 parts by weight Haven't tested these, no idea of the "gotchas". Not having seen details of colored Flash elsewhere, might be a field for research, including the best way to get "flash" as opposed to "bang". Ellern, Millitary and Civilian Pyrotechnics, alludes to a company in California selling several different colors of Flash, but gives no formulas. A Flash from The WiZ A note came in from The WiZ (Which wiz? The ONLY WiZ, the WiZ from the PGII.) Some interesting ideas about flash, and its employment, originating with some material from Westech. This month some compositions, then some novel applications. Still looking for notes on "flash without bang", which seems to be a matter of construction. Reminder... Flash is probably the most hazardous of all pyro compounds. Know what you are doing, or get help. DO NOT ball mill mixtures. DO NOT mill mixtures in any way. The ONLY known method of making flash type mixes with any safety is small batches, by the diaper method. The Blue employs Paris Green, one of the more toxic compounds. RED: Magnesium powder 1 Strontium Nitrate 1 GREEN: Magnesium powder 10 Barium Nitrate 10 PVC 1 YELLOW Magnesium powder 1 Sodium Oxalate 1 Potassium Perchlorate 1 VIOLET Magnesium powder 10 Potassium Perchlorate 10 Cupric Oxide 3 Strontium Nitrate 3 PVC 1 BLUE Magnesium powder 20 Potassium Perchlorate 20 Paris Green (!!) 6 PVC 1 The magnesium should be 100 mesh, or finer. The color is most apparent, it seems in the light from the flash, as it falls on other things, than in the material itself, being somewhat washed out by the brilliance of the flash. Any confinement leads to an explosion.