bigboi Posted May 22, 2005 Posted May 22, 2005 I was watching a show bout firefighters. To burn off flammable underbrush in forests so they dont ignite later, they filled ping pong balls with a chemical and dropped them from helicopters into the area that they wanted to burn the underbrush in. When filled with the chemical, the balls would ignite with a few seconds delay, i think it was 7 seconds. Does anyone know what the chemical could be?
akcapr Posted May 23, 2005 Posted May 23, 2005 ping pong balls are made out of celluloid. From what i hear its like most part nitrocellulose or something. It depends on what oxidizers would be hypergols with celluloid.
YT2095 Posted May 23, 2005 Posted May 23, 2005 it`s Potassium permanganate and an ethylene Glycol injection just before deployment.
jdurg Posted May 23, 2005 Posted May 23, 2005 I know that normal ping pong balls have some small amount of butane in them, I believe. (The only reason I know this is because while in college we lit a whole bunch of ping-pong balls on fire, and a nice clear, blue-flame came jetting out from an open hole we created in the ping-pong ball).
YT2095 Posted May 23, 2005 Posted May 23, 2005 these ping pong balls are already pre-drilled and filled then sealed and packed before getting onboard the chopper. the Gas inside is long gone before that
akcapr Posted May 23, 2005 Posted May 23, 2005 then how do they ignite if they are pre-filled? some kind of pin u pull?
H2SO4 Posted May 25, 2005 Posted May 25, 2005 yes, but some thing has to start it by mixing it (breaking a baggie of the glycol) so that it goes. How is this done?
Borek Posted May 25, 2005 Posted May 25, 2005 Ethylene glycol can be replaced be glycerine if I recall correctly. You just inject glycol into the dry permanganate. It gets hot due to glycol oxidtaion until it starts to burn. Ping pong ball is made of nitrocelluloid so once it starts to burn it gives long flame. We made smoke bombs from ping pong balls when I was a kid Best, Borek -- Chemical calculators at www.chembuddy.com pH calculation concentration calculator Smarkotan oz gluthozmaz
YT2095 Posted May 25, 2005 Posted May 25, 2005 Borek; you`re exactly correct on both counts, only Eth Gly is used as it gives a longer time before ignition H2 READ post #8 it clearly states that potassium permanganate is in the NC spheres, and just before deplyment ethylene glycol is injected into them, WHAT PART don`t you understand here?
akcapr Posted May 25, 2005 Posted May 25, 2005 is ethyle glycol added to potassium permangabate solution or crystals?
Borek Posted May 25, 2005 Posted May 25, 2005 Just liquid. If it was a solution (ie mixed with water) I doubt there will be strong exothermic reaction. Besides, how do you want to inject crystals? Best, Borek -- Chemical calculators at www.chembuddy.com pH calculation concentration calculator
akcapr Posted May 26, 2005 Posted May 26, 2005 well how do u inject a non-solution of potassium permanganate?
Tetrahedrite Posted May 26, 2005 Posted May 26, 2005 well how do u inject a non-solution of potassium permanganate? arrghhhhhh!!
YT2095 Posted May 26, 2005 Posted May 26, 2005 re-read the entire thread again! it`s closed now as the question has been answered and I don`t have time for this stupidity!
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