oldguy Posted February 6, 2011 Posted February 6, 2011 The majority of ground type road safety flare/fusee’s contain from about 6 to 16% sulfur as a fuel, and to reduce the ignition temperature. The nasty part is that flare/fusee comp’s containing that much sulfur produces significant amounts of choking toxic sulfur dioxide gas. My question is: What can the sulfur be economically replaced with that is relatively comparable (serves the same function), but doesn’t emit such a nasty gas?Thanks for any help in the right direction.
dagabu Posted February 6, 2011 Posted February 6, 2011 No, I dont think that the sulfur is for fuel, I believe it serves the same function as it does in black powder, it reduced the temperature needed for the comp to burn. That comp would go out without the added sulfur so the key is to find another chemical that will sensitize the comp but not react with it. I have some red comp that will not stay lit without sulfur, it is a necessary evil.
FUZE Posted February 6, 2011 Posted February 6, 2011 (edited) Dear, Dababu Just some food for thought have you tried using boron? Although it produce's a green flame I have used it in the past for grenade fuze's. As per my pressed time delay, The ratio was (70% KNO3, 25% C, 5% B ). This composition when pressed into a 5mm wide x 25mm long cylinder and will provide a delay of approx. 3-5 seconds. That being said boron burns hot so it can keep a compound burning but the green flame makes it un-usuable in most stars. Boron has been about the only chemical that I have really substituted sulfur for. Old guy said it best "it's a necessary evil" Edited February 6, 2011 by FUZE
NightHawkInLight Posted February 6, 2011 Posted February 6, 2011 You got who said what backward there fuse. Though I know of nothing that works quite so well as sulfur, I really don't think it will provide as much of an issue as you may think. Just try to keep the percentage as low as possible. You would need to stick your nose right into the smoke for the SO2 to be at uncomfortable concentrations. Until you get to 15-20% sulfur I rarely notice the SO2 in the smoke. Remember that some of the sulfur is used up forming other compounds as well.
Mumbles Posted February 6, 2011 Posted February 6, 2011 Sulfur is certainly a fuel, at least primarily. It's not a catalyst. It clearly forms compounds like SO2, Potassium sulfate, etc. At the same time it also forms stuff like K2S, where it would be acting like an oxidizer if formed directly, as opposed to being reduced from the sulfate by other stronger fuels. Sulfur is such a good sensitizer because it has a low melting point. Other things such as lactose, hexamine, and the like may be able to preform similarly.
oldguy Posted February 7, 2011 Author Posted February 7, 2011 (edited) I bought a few lbs of Hexamine & tried some @ differing ratio's. Thumbs down there, as it would hardly ignite & caused sputtering once ignited. Ascorbic acid or one of the sugars sounds like it might do the trick. I will test them. http://www.google.com/patents/about?id=HjQQAAAAEBAJ&dq=black+powder+substitute http://en.wikipedia.org/wiki/Black_powder_substitute http://www.whitemuzzleloading.com/black_powder.htm I do a little mycology, home brewing & distilling as other hobbies. So I had several types of sugars on hand you would not find in an ordinary kitchen. I just tried several with mixed results. Dextrose worked fairly well. Best of the bunch was a dry malt = maltose used for beer brewing. Light dry malt is micron sized & is air blown to remove moisture. Comp 9 Visco ignited, fast ignition & going full blast Comp 9 dying down Comp 9 done, very little residue, burned brilliant, HOT & the smoke was not the choking type or seemed toxic smelling at all.99,7% of the residue shown on my burn plate is from previous burn off's of other comps. Edited February 7, 2011 by oldguy
Mumbles Posted February 7, 2011 Posted February 7, 2011 Perhaps I didn't mention that they were not 1:1 substitutes.
oldguy Posted February 7, 2011 Author Posted February 7, 2011 I came to realize that fact very quickly. BTW, back yard is 5 acres & I built & use a stand behind blast shield, in case one of these experimental comps propagated in an unexpected manner. Spark effect was from intentionally including some rather course charcoal. I wanted “sparks” so I could gauge the gas/flame envelope size better. On a side note, with a little more experimentation I also found adding a wee bit of incense changes the smoke smell to tolerable, even somewhat pleasant.
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