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ecos
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I always use PVC pipes,i follow these steps: http://youtu.be/12fR9neVnS8
You will find a compressing stage using a hammer in the above video,Thats why i want to avoid any sensitive composition.
[Edited on 24-2-2015 by ecos]
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PHILOU Zrealone
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EC = European Community
CE = Communauté Européenne
Thus the same  but with a french touch 
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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jock88
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Is the second one not arabic?
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ecos
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My concern now is the binder percentage. Nakka's project used 11% binder. The improved formula uses around 5% binder.
Most of papers uses high percentage of binders like :http://www.eucass-proceedings.eu/articles/eucass/pdf/2009/01/eucass1p81.pdf
How could i calculate the correct % needed for my composition?
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PHILOU Zrealone
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Quote: Originally posted by ecos  | My concern now is the binder percentage. Nakka's project used 11% binder. The improved formula uses around 5% binder.
Most of papers uses high percentage of binders like :http://www.eucass-proceedings.eu/articles/eucass/pdf/2009/01/eucass1p81.pdf
How could i calculate the correct % needed for my composition? |
In Brico shops inside Europe, there are some "silicone like cartige" of polymer glues (Power Fix and the like) wich display very good combustion on
their own. By determinating and calculating the centesimal composition of those polymer, you may find the best OB ratio and thus determine the ideal %
of binder.
Note that silicone doesn't burn completely or well because of the inert SiO2 resulting from its combustion... the SiO2 formed often prevent further
burning and flame propagation into the silicone mass. It is like glass coating forming at the surface.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Bert
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PLEASE! DO NOT MIX A LARGE BATCH OF ROCKET FUEL WITH CYANOACRYLATE GLUE!!!
The reaction that cures these glues is EXOTHERMIC.
Take a cotton ball and dump a bottle of "super glue" on it. Check out how the temperature rises
Do you want to have a thermal runaway in a fuel grain? Maybe inside a metal mould, just to increase the fun...
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ecos
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Thanks for the precaution Bert.
I would like to understand something, If I used Thermite for ignition , why doesn't the compositions explode?
The detonation temperature of AN is 500 degrees and thermite would generate more heat than this.
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Bert
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I am going to perform a little experiment- I've some dry lacquer grade commercial nitrocellulose, very fine powder. And a bottle of cheap dollar store
cyanoacrylate glue.
The YouTube videos of cotton balls catching fire when saturated with superglue are apparently "improved", I am interested to see if dry NC will truly
ignite unconfined when saturated with superglue.
Cotton ignites about 255 C, nitrocellulose about 170 C. I will report results-
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ecos
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@Bert, Looking forward for your results.
| Quote: Originally posted by ecos | Thanks for the precaution Bert.
I would like to understand something, If I used Thermite for ignition , why doesn't the compositions explode?
The detonation temperature of AN is 500 degrees and thermite would generate more heat than this.
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in addition to this question , do I need to use PSAN-I instead of AN for my composition or silicone would be enough to make phase stabilization as
well ?
Ref : http://www.wickmanspacecraft.com/psan-i.html
[Edited on 27-2-2015 by ecos]
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Fulmen
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AN doesn't detonate at 500°C, in fact the combustion temperature is probably in the 1500°C range.
We're not banging rocks together here. We know how to put a man back together.
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Bert
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| Quote: Originally posted by ecos |
I would like to understand something, If I used Thermite for ignition , why doesn't the compositions explode?
The detonation temperature of AN is 500 degrees and thermite would generate more heat than this.
|
AN mixtures near STP generally require a shock to detonate, often needing a booster explosives as well as a blasting cap . AN decomposes FAR slow 500
C, around 210 C.
| Quote: |
in addition to this question , do I need to use PSAN-I instead of AN for my composition or silicone would be enough to make phase stabilization as
well ?
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You only require phase stabilized AN if you are going to store fuel grains or grained propellant powders at fluctuating temperatures, the upper
transition temperature which typically causes the grains to break up is about 32 C. There are other methods to reduce the cracking of case bonded fuel
grains from temperature cycling as well-
http://www.google.com/patents/US2957309
For an experimental rocket motor made in a European winter, stored at indoor temperatures and fired soon after production, phase stabilization is
probably not required. If you need to keep the motors for months or years in an outdoor magazine in the summer sun, where the fuel crosses the
transition temperature twice a day? You would need to deal with the phase change.
[Edited on 27-2-2015 by Bert]
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ecos
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I think AN detonated around 300 degrees : https://www.youtube.com/watch?v=GxKXAbS7WAo
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Bert
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I think that pointing a blow torch at an oxidizer sample on a brick with unknown composition/contaminants and no instrumentation doesn't = precise
information.
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Fulmen
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Short answer: No.
Long answer: Hell no! 
As Bert put it, one murky video off Youtube does not represent good data. Trust me, it's called rocket science for a reason. There is a ton of
information freely available on the net that will explain this in detail, but it takes time and the proper fundamentals to understand them.
Don't believe me, go see for yourself. Both the suitability of AN propellants, their performance and explosive properties can be found, and they will
tell you that we're right.
And if I might speculate a bit, this "detonation" seems like just the thing you could get by heating a brick with a blowtorch. Rapid heating of a
brittle material with low thermal conductivity can create "explosive" cracking.
[Edited on 27-2-15 by Fulmen]
We're not banging rocks together here. We know how to put a man back together.
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ecos
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sorry for using youtube as reference.
I went through some articles that discuss "polymeric binder"
| Quote: |
since hydrogen has higher combustion energy per unit weight than carbon, a hydrocarbon with high H/C ratio is preferred
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silicone according to this statement is not the best.
i also noticed found that epoxy has higher H/C ratio compared to Neoprene !
epoxy is very hard when it is dry and Neoprene-contact cement is also very solid
any suggestions ?
[Edited on 2-3-2015 by ecos]
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Bert
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What mechanical characteristics does your motor design/performance/fuel grain require?
Answer that, and you can decide if you'd like a soft rubbery grain, or rock hard-
As an example, some people I know of who mere making larger and larger motors for very high acceleration applications started to have mid air
catastrophic engine failures (KABOOM!). The fuel that had been well suited for the smaller engines was TOO soft and rubbery, was slumping under 100's
of G acceleration, pulled away from the motor walls and exposed the grain outer sides to the flame- Too large a surface area burning, engine blows
from over pressure.
Similarly, you may have a failure if you make a hard, brittle grain and crack it from handling or temperature cycle induced expansion/contraction.
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Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Fulmen
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Agreed. While a high H/C-ratio might increase performance it is of little interest if the mechanical properties suffer as a result. A suitable burn
rate is just as important, especially with AN propellants which require a high Kn even under the best of conditions. And then you have to consider
cost and availability, the best choice for you might not be the one with the highest performance.
We're not banging rocks together here. We know how to put a man back together.
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ecos
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very interesting.
I am planning for small grains most likely for fireworks. max 100 meters high.
Nakka used Neoprene-based contact cement as a binder. he should have a strong grain but it seems due to volatile materials there were tiny pores which
affected the performance so he used another method.
| Quote: | Since an appreciable percentage of the contact cement is volatile solvents, the resulting grain would unavoidably have very tiny pores. This was
recognized as a potential downside, however this technique was considered to be a viable method, at least for initial testing. Since the AN / Aluminum
formulations are difficult to ignite, it was felt that even though hot combustion gases could seep through the tiny pores, the affected material would
not actually ignite. Test firing of motors prepared in this manner supported this hypothesis. A couple of such test motors were fired. Although hard
to ignite, combined with erratic burning, the results were nevertheless encouraging. This method of grain production was soon dropped, however, due to
lengthy time required for a grain to "dry". It was found (by regular weighing) that weeks were needed to get a solvent-free grain.
After pondering various ways to purge the solvent in an efficient manner, it was found that the most effective way was to drive out the solvents prior
to forming the material into a grain. Once completed dried, which would only take a few hours if heated slightly, it was found that breaking the dried
material up into small granules and then compressing them, that a surprisingly robust grain resulted. This basic method has since been employed for
all subsequent motor grain preparation
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I don't think the result grain would be as tough as epoxy !
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Bert
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If you just want consumer fireworks rocket level of performance, you are WAY over thinking this. Black powder, cheap, simple, requires only minimal
and easily home made tools.
It is perfectly fine to explore higher performance fuels and their design parameters, and learn everything you can, of course! Especially, learn your
design THEORY.
Eventually, one leaves the drawing board or books behind and tries an experiment. At that point, simpler and less demanding techniques that can be
easily made to WORK may start to look much more attractive...
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ecos
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Totally agree  but black powder is an issue to buy thats why i prefer AN
i am almost ready with the things i have , I have AN, Al powder , sulfur , binder
those are the binders i found in my hardware store :
1- RTV Silicone
2- Epoxy like : http://www.bison.net/en/products/647-2-components-adhesives/...
3- CPVC cement(it contains : tetrahydrofuran 109-99-9, methyl ethyl ketone 78-93-3, cyclohexanone 108-94-1)
could any body help regarding which one should i try?
[Edited on 4-3-2015 by ecos]
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ecos
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I couldnt stay much , i already tried the RTV silicone
I started with 5% binder but it was not enough , i started to increase till i reached this ratio :
AN : 59 %
Al : 16 %
S : 0.7%
Binder : 24%
it seems i increased the silicone too much 
my samples :
they don't look nice but you can say my first trial with AN
I left them to dry and tomorrow i will drill a hole for testing the burning rate.
[Edited on 5-3-2015 by ecos]
[Edited on 5-3-2015 by ecos]
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Bert
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1: If you have access to ammonium nitrate, Potassium carbonate (wood ashes!), charcoal and Sulfur- Why do you think you need to BUY black powder?
Making this is not difficult, or more dangerous than some of the other fuels you have contemplated...
2: If you simply MUST use AN, have an hydraulic press and a support sleeve, it is possible you need no binder. Amonpulver grains for artillery use
were made in hydraulic presses with nothing but ammonium nitrate and charcoal, although some formulations contained small amounts of Sulfur .
Please see Tenney Davis: Chemistry of Powder and Explosives in the library for more information on amonpulver.
http://library.sciencemadness.org/library/books/the_chemistr...
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ecos
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Thx Bert,
I will give amonpulver a try but I need to close the story of the samples I prepared.
for the ignition , I couldn't find CuO to prepare CuO/Al , I have Zn dust and
Sulfur. would it work ? I think to use mini bulb for a sample of 2 grams of Zn+S as igniter charge. what do u think ?
[Edited on 5-3-2015 by ecos]
[Edited on 5-3-2015 by ecos]
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Bert
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Manganese dioxide from carbon battery with Aluminum powder makes a thermite, or you could spend half an hour looking at the Copper chemistry threads
and learn to make your own Copper oxide.
The MnO2/Al thermite is also a rocket fuel with a specific impulse comparable to black powder, which may be compacted into a motor casing
with hydraulic press, or even rammed with drift and hammer. Exhaust from such an engine includes gaseous manganese, which burns in air behind rocket,
the light is blinding if fired at night. Don't make these in PVC tube unless you line it with something like carbon fiber cloth, and be aware the
extremely hot Aluminum oxide in exhaust erodes pressed clay nozzles very quickly. If you use a sky rocket stick to stabilize, it WILL be on fire when
it comes back down...
[Edited on 5-3-2015 by Bert]
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ecos
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Got it , I found some videos to support on youtube.
but whats wrong with Zn+S ?
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