chemrox
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powdered Zn
Back in the day, I made rocket fuels and pipe bombs with mixtures of powdered Zn & Sulfur flowers.
How would Zn stack up against Al in some of the mixes here?
My inorganic consists of point groups & symmetry
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quicksilver
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In what context do you mean "stack up"? - As a "fuel to fuel" basis the comparison would need to take into account size shape and purity of the
particle matter from both groups then if you were just talking about oxidizer/fuel type stuff....
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YT2095
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I just tried it and it did nothing beyond just burn the sulpher off?
10micron alu and RG sulpher powder.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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12AX7
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Aluminum is nice and chemically resistant to some things.
I've never had aluminum (filings) burn in thermite until rather high temperatures were reached.
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quicksilver
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well I was introduced to S/Zn as a rocket fuel when I was much, much younger and it works but you need to compress it, etc.....compair it to KNO3 and
suger or BP and the later have a faster burn rate. IF WE ARE TALKING ABOUT ROCKETS... Sulfur and zinc has some push which was valued - however faster
burn rate wasn't always the objective in a launch. Back then the best for speed of burn that I used to work with was ammouium perchlorate and aluminum
flake in a polymer pellet (formed in rocket tooling, bla, bla) THAT was very powerful -=and=- fast for larger sized motors. The big ones that guys
used to make in the club I used to be in were almost military sized and astounding in what they could do. Once, a club in Phoenix AZ had to get in
touch with the FAA before a launch due to size and flight considerations! (NO bullshit!) That thing was the size of a Tomahawk and flew like nothing I
had seen before. That was when they first started using altimeters and various electronics. Today they use them on most rockets due to recovery
efforts of the clubs involved (mucho dollars spent now-a-days)... Hell, I don't
even know if we are talking about rockets - I just interjected it as S/Zn was a rocket fuel that I used.
[Edited on 19-1-2007 by quicksilver]
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YT2095
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well I only made about 100mg, as I had no idea if it flash off or something unpredictable. maybe that`s why? I used a mini blowtorch to light it, the
sulpher burned great 
I must admit, I did expect it to do Something more than it did
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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CPC
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Powdered Zn
I've experimented with various rocket fuels including Zn/S. I added red gum to the Zn/S and then acetone to dissolve the red gum. Upon loading into
the rocket motor and allowing to dry (evaporate the acetone) I had a very compact, strong cylinder of rocket fuel that never CATO'd.
CPC
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Zinc
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In what ratio should Zn and S be mixed?
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Xenoid
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| Quote: | Originally posted by Zinc
In what ratio should Zn and S be mixed? |
If you don't know that you probably shouldn't be mixing them....
Zn + S ---> ZnS
1 mole Zn + 1 mole S ---> 1 mole ZnS
65.37g + 32.06g ---> 97.43g
So roughly 2 parts Zn to 1 part S by weight.
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Mr. Wizard
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The ratios of S and Zn can be calculated as Xenoid did in the previous post, BUT, the best thrust may not be from that exact ratio. The rate of
burning and the temperature of the exhaust 'gas' may be tilted to a more favorable direction by changing it. For example a little more Sulfur may not
be needed to completely balance the Zinc, but it may speed up the reaction and provide a quicker burning with easier ignition and better thrust. It
may provide a better bond for grain formation and as a gas that can be heated up and ejected at a higher speed. Part of the fun of rocketry was the
experimentation with these small changes, and figuring out why.
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Zinc
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Xenoid I knew that it can be calculated that way. Mr.Wizards posts explains why I asked.
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Mumbles
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I believe the normal ratios are normally quite close to stoichiometric. My notes show a ratio of 67 zinc to 33 sulfur as pretty common. Pretty much
2:1 I also have something about the addition of 10% potassium nitrate was said to give a little more zip to the rockets. I'm not sure if this is 10%
additional, or if it replaces the zinc or sulfur. While zinc uses sulfur as an oxidiser, the potassium nitrate would be able to use it as a fuel,
both chemicals actually. I never experimented much with these, so these are notes I took from reading/hearing accounts from others.
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quicksilver
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CATO's in rockets is almost always traced back to inconsistent packing. That's why the hobbyists started packing with automobile jacks and developed
super heavy compression (without impact, of course). You can do some wild experiments with the right tools for construction. The perchlorate / Al fuel
was perhaps the strongest thing I personally saw. But there are guys who make black powder rockets that can push 2-4 lbs of stuff up to 6,000 ft. It
just depends on what you want to spend. But the minute you have cracks or air pockets in the motor, all but the slowest thrusting motors will suck. I
saw a sugar-KNO3 rocket that was made from PVC pipe, that even painted day-glow red went out of sight before you could follow it with the human eye.
That's why before we had (or could afford) altimeters, we made them pop at the height of their flight; so we could see how high we got!
[Edited on 11-1-2008 by quicksilver]
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