rocket prepellant in the lab

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havoc821

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Other day while in Chem II class ( 5 minutes before the bell rang) we had our off topic time and somebody asked if we could make TNT in the lab and of course the answer was no. While on the topic of making stuff in the lab, I asked if we could make AP. She said she wasn't sure about the school regulation. So i thought for a second and tryed to think of a propellant that wasn't regulated and suddenly sugar motors popped into my head after hearing Johnny Paul's and Todd Lumpkins talk about them. So I asked if we could make KNO3 (potassium nitrate) in the lab and she said the we could and she already had those chemicals in the lab. SCORE!!! She (my teacher) is now very interested in making rocket propellant in the lab. We will for sure make the oxidizer (KNO3) but not sure yet if we want to add the fuel because that is when things can get out of hand. She was wanting to put the propellant and make it into an actual motor and fire it in one of my rockets but I told her that we probably shouldn't because that is a whole set of more things to do. It would be pretty hard to make a casing and nozzles considering I don't have or have any plans of buying a lathe. I have been advised from making the complete motor (we were just going to make the propellant and just light a small pile of it in this special thing in the lab that has a protective glass shield, but she is really interested in the complete motor and I was wondering if there were any safe and eay ways to make an actual motor. It would be an endburner (core burning too complicated right now) and probably no bigger than the G size range. Maybe H or I but probably not. Does anybody have advice or anything to offer? I'm not asking for recipies or anything (I can get those on the internet anywhere) just more or less, the motor application part. Thanks!
 

Elapid

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entail the Chem Prof. piling Sodium peroxide mixed with sugar in stoichiometric ratios onto a fireproof surface, then pouring a few mL of regular tap water on the mixture...

the students are surprised that water can START a fire...

the other Professors are irked at the smoke that suddenly inundates the study hall.
 

Ryan S.

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KNO3 sugar DOES NOT have a high enough burn rate (unless some catalyts are used) to be used as an endburner. You really need to make a core burning motor in order for it to work.

end burning motors are tricky, you need lots of insulation

As far as casings go, www.lokiresearch.com

you can get a nice case for 40 bucks
 

havoc821

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does that 29mm case come with closures? Can you buy nozzles from them for that case? Since endburners won't work, how would I make the core of the propellant grain/ I would rather not use a drill bit (turned SLOWLY of course). Is it really coing to be that complicated if she/we choose to do the whole motor route? I mean there is no problem when it comes to the propellant (she's a Chemistry teacher) but I don't have too much knowledge when it comes to the whole motor part. Is this pretty much what I need for the motor:

propellant (DUH)
casing and closures
nozzle
liner
O-rings

It can't be that simple can it? I can order the nozzle, liner, o-rings, and casings from Loki Research and then all I have to do is make the propellant? Is that all? That doesn't seem right. What about AN (ammonium nitrate) is that regulated and does it involve a lot? What catalysts are needed for the KNO3 to work as an end burner? Just curious. Are we getting too ahead of ourselves? I know people are going to say that I'm too young to try this or I don't know what I'm doing but I don't have to worry about the propellant part (teacher will mostly do that and I will help under her supervision of course) but yes, I do need help with the motor part. So before you go shooting down our ideas (I saw what you guys did to Neil when it came to stuff like this and his L3 dreams) could you guys offer some advice? Thanks!
 

havoc821

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also, are these nozzles single use (like made out of graphite) or reusable (made out of metal)? I would think metal because a 29mm nozzle was $20! Thanks!
 

havoc821

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also, do the snap rings have to be used or can I use some other form of retention. If they do, where can I find a pair of snap ring pliers and how much would they be? Thanks again!
 

solrules

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Nozzles arre graphite. They can be used many times (20-30 flights, IIRC). If you went the whole motor route, you would need to get casting tools, release spray, casting liner, etc. You should run Rickard Nakka's Propellant simulator (MS Excel) BEFORE you order parts. Get all the literature you can get your hands on. Design before you spend money.
 

Ryan S.

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if you order a 29mm motor you get everything; nozzle, snap rings, bulkhead, and o-rings.

The nozzle is made out of graphite and is reusable. Graphite is much more resistant to erosion than metals.

www.mcmaster.com is your source for snap ring pliers and o rings

driling the grains is a perfectly resonable idea.

look at nakka's site for a way to cast the griains. Recrystalization is the usual route here.
 

havoc821

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this is looking to be much more trouble and expensive than I thought. I think for now we may just stick with making the propellant and save the motor stuff for later. Could the KNO3 propellant be used for endburners in like C motor sized stuff? I just got done spending a lot of time reading Richard Nakkas PVC motor stuff and it seems pretty intense. If we went the motor route, I would order a casing nozzle, o rings, and closures from Loki to save a lot of time and trouble. The casting for the 29mm G stuff should be too hard. I can use 24mm motor mount tubing and 24mm couplers for casting tubes and liners. I wouldn't have a delay element (too complictaed). This is very interesting but I will discuss this more with her on Tuesday wehn I get back to school. It seems that KN/Sorbitol would be a good choice because the Sorbitol is easily available and not regulated. Let me talk to my teacher and we will go frm there. Thanks for all the info guys!
 

Johnnie

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"Not regulated..."

I guess that depends on the agents interpretation. Granted KNCP is not on the list, but they (BATF) are trying to group together anything that is made with potassium nitrate is concidered an explosive. The field agent who has been working the guys in the HARA club, has taken this definition, and therefore considers "candy" propellants regulated...:mad:

Thats why I am taking on the task of learning Paraffin hybrids, 2 items that would be hard to explain why they would need to be put on the list, even for the BATF...I'm sure they are working on it though.

Good luck with the science project.
 

DynaSoar

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Originally posted by havoc821
this is looking to be much more trouble and expensive than I thought. I think for now we may just stick with making the propellant and save the motor stuff for later. Could the KNO3 propellant be used for endburners in like C motor sized stuff? I just got done spending a lot of time reading Richard Nakkas PVC motor stuff and it seems pretty intense. If we went the motor route, I would order a casing nozzle, o rings, and closures from Loki to save a lot of time and trouble. The casting for the 29mm G stuff should be too hard. I can use 24mm motor mount tubing and 24mm couplers for casting tubes and liners. I wouldn't have a delay element (too complictaed). This is very interesting but I will discuss this more with her on Tuesday wehn I get back to school. It seems that KN/Sorbitol would be a good choice because the Sorbitol is easily available and not regulated. Let me talk to my teacher and we will go frm there. Thanks for all the info guys!
Make S/U motors.

Take an empty paper motor casing such as comes with kits for engine block spacing. Make your grain to fit it.

Get with the art department and make a clay nozzle. A little research can find what clay can take the heat and not crumble. Mary at Estes might can tell you what kind of clay they use.

Insert the grain. Use JB Weld to glue the nozzle in. Glue a cap with a hole on top the grain -- think of how a 20/50 centering ring sits inside a BT50.

If you need a sliver of BP or APCP in the core to get it going, put it in before the nozzle.
 

Zippy

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If you want to make low power motors you can do it incredibly cheaply. Just look up "The Incredible 5 Cent Sugar Rocket" on the web. The basic design is easilly upscaled to loft a small LPR rocket. The nozzles are made of Durham's Rock Hard Water Putty. The casings are rolled from mailing tape. I've made them myself but just as large bottle rockets.
 

cdma77

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If you are going to make sugar motors or AN based motors you are going to need 54mm cases. 29mm cases will work but it takes a lot of sugar based propellant to get the performance of an APCP motor
 

Missileman

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54mm not needed. You don't have to build a high power motor.
You can get a nice C or D impulse in a 29mm.
AN regulated?
AN (salt peter) is used as a curing agent when picling meat (among other uses) Does that mean I need a LEUP next time I make corned beef?
 

cdma77

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AN is Ammonium Nitrate, not Saltpeter. KN03 is Potassium Nitrate, or Saltpeter. One does not need a permit to make ANCP motors.

Jeff
 

powderburner

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In this lawsuit-happy society of ours, I am surprised that your school system would allow your teacher to prepare and ignite this sort of chemical mixture----even with the use of safety equipment/procedures, common sense, and experience.

Instead of trying to demonstrate the relatively high performance necessary for a rocket motor to fly (thrust-to-weight of the complete motor system will have to be pretty good to lift a rocket safely, but we already know that), there are other options.

A static test stand firing is too boring to get the interest of most kids. Let's face it, it only has significance to us rocket nerds.

A rolling model 'car' could be the answer for your motor demo. The weight of the motor becomes less important, and you can get some impressive performance even with a low-thrust motor. And if you can keep your creation on the ground it might be a bit more safe? Use large wheels to reduce rolling resistance on a rough parking lot surface. Use a wide stance and a good wheelbase for vehicle stability. You may want to use fins on the back for aerodynamic stability once it gets up to speed.
 

KermieD

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And a guidewire to ensure it stays on track. One overlooked pebble and you have a problem.
 

DPatell

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Do not go the cheap route in EX rocketry. It will bite you in the @$$. Buy the best quality materials of what you need to get the best results.
 

Ursa_Major

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I know we shouldn't discuss EX on here, so I won't. But I will point you to a very useful website for information on SU sugar motors: www.jamesyawn.com . The clay you need for the nozzles is Bentonite clay - solidifies under pressure, and you can drill a throat through it.

Just make sure you read, re-read, and read again all the safety stuff first, and make sure your teacher reads the site thoroughly too, so she's familiar with the caveats. Don't skim-read, and if you don't understand, just walk away from the project, don't push it. Pride doesn't burn, but skin does.

Your first 3 considerations should be, in this order, safety, safety and safety.

Remember - if you don't know what you're doing, DFDI*!!

G.

* Don't F*in' Do it, in case you were wondering...
 

Mr.Rocket

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I would recommend starting out the 5 cent sugar rocket report, just do a search. I started out on these, the ones that work go up several hundred feet and the tools are easy to make.
 

havoc821

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Hey everybody! Thanks for all of the help and advice! I will start with something simple such as a KNO3/sugar motor and progress with different fuels. My teacher has ruled out chlorates because of their unstability, so sorry guys, no AP. :( We probably won't put this into a rocket for a while, just for safety issues. Since it will be too expensive to order a casing/ nozzle, etc, I will got Homer Hickam style and use some of that electrical tubing pipe (probaly strat with a 38mm motor) and make a nozzle out of a washer welded onto the end. Yes this is crude but I am starting simple. I will experiment with sorbitol and sucrose mixtures as well. This is looking like it will be lots of fun but don't worry we will be very safe. Thanks guys! :D
 

Mr.Rocket

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Sorry, but metal cases for amature rocketry is a bad idea, one cato and you may die, rule of thumb....if you can see it, it can kill you. I would recommend you make casings out of kraft paper because the wont cause shrapnel, and nozzles out of clay.
 

Ryan S.

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Originally posted by mr.rocket
Sorry, but metal cases for amature rocketry is a bad idea, one cato and you may die, rule of thumb....if you can see it, it can kill you. I would recommend you make casings out of kraft paper because the wont cause shrapnel, and nozzles out of clay.
that isnt true, when using a fragmenting metal you are right, however, Aluminum (which is what is used) does not fragment and is therefore safe for use. In the RARE event that an aluminum case blows out the side, it peels like a banana, and does not fragment.
 

solrules

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Originally posted by Ryan S.
that isnt true, when using a fragmenting metal you are right, however, Aluminum (which is what is used) does not fragment and is therefore safe for use. In the RARE event that an aluminum case blows out the side, it peels like a banana, and does not fragment.
Plus the fact that many aluminum cases are made to withstand 2000 PSI pressures with a 2x safety factor. Nozzles usually fail before that, making AL based motors very safe.
 

Zippy

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Unless you are willing to use a factory made (or well made by an amatuer craftsman) aluminum case I would also recomend staying away from metal. Remember your teacher is thinking of a safe project that all the class members can participate in too. You can roll many smaller, safer kraft tubes and test burn plenty of them for a low cost. You may understandably want to make the biggest motor you can but a better learning experiance for the other students is to have hands on experiance.
On a side note you are pretty lucky to have a teacher that will do this and a school that actually has some of the stuff needed to start with. In my last science class (many moons ago) we couldn't do any actuall experiments for lack of even the simplist materials. We didn't even have gas for the bunsen burners. :(

EDIT: Timing is everthing. Ignore my metal comments since they were covered by others before I could post.
 

jyawn

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I just happened upon this fine forum and lo and behold... my name and not in vain!

Nice to see that someone actually reads my pages, especially the safety part!

Experimental motors can be made safely, but it takes a bit of knowledge, maturity, and restraint to keep from getting burned. Seems like "havoc" and his teacher might qualify.

I understand that this forum is not about experimental rocketry, so instead of muddying the waters here, I suggest contacting me directly, and getting that chem instructor to do so too.

Experimental rocketry is not about being cheap. Purchasing certified motors is cheaper. Experimental is about learning.

This might be a fine opportunity for you to teach the teacher. Seems like you might have more knowledge and maturity regarding this endeavor. If she has never built and/or flown a model rocket, you might want to encourage her to attend a launch, build a kit, and learn the ropes.

Once the airframe, recovery, launch systems, launch site, and attitude toward safety are worked out and proven functional, then might be a good time for her to take on motor construction.

So please feel free to contact me directly, and to forward my name and e-mail to your instructor!

Sincerely,
Jimmy Yawn
[email protected]
www.jamesyawn.com
 

DynaSoar

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Originally posted by Ryan S.
that isnt true, when using a fragmenting metal you are right, however, Aluminum (which is what is used) does not fragment and is therefore safe for use. In the RARE event that an aluminum case blows out the side, it peels like a banana, and does not fragment.
I will not describe the processs and events whereby I disproved the assertion that aluminum will not fragment. It is precisely the sort of thing that BATF would enjoy hearing because it would prove their point regarding "other" uses of propellant. It was 35 years ago.

Regardless, a metal motor and nozzle at high speed is dangerous. It is also likely to be so far outside the allowable activities for the school's liability coverage that attempting to do it there will result in not being allowed to return, at the minimum.

There are safer, easier alternatives. These should be explored and learned from thoroughly before attempting to move on to metal. Dollars to donuts, if you asked Homer Hickam if he'd have used safer alternatives had they been available, he'd say yes.
 

MarkABrown

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Originally posted by havoc821
I will start with something simple such as a KNO3/sugar motor and progress with different fuels. My teacher has ruled out chlorates because of their unstability, so sorry guys, no AP.
Chlorates and Perchlorates are two totally different things. Perchlorates don't have nearly the stability issues as a chlorate does.
Originally posted by havoc821
Since it will be too expensive to order a casing/ nozzle, etc, I will got Homer Hickam style and use some of that electrical tubing pipe (probaly strat with a 38mm motor) and make a nozzle out of a washer welded onto the end. Yes this is crude but I am starting simple.
Electrical tubing is not aluminum, to the best of my knowledge, and welding a washer for a nozzle is just asking for trouble. There is a reason that experimentalists today use the materials they do. They've proven more reliable and safe than the things Homer Hickam used in the 50's. Please reconsider trying to start EX "on the cheap" and be safe.
 

powderburner

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Originally posted by solrules
Plus the fact that many aluminum cases are made to withstand 2000 PSI pressures with a 2x safety factor.
Even if the tubing IS aluminum (and I have to agree with Mark Brown---the only conduit material I have ever seen is steel), and even if it IS rated at 2000 psi, that does not make it safe for a rocket motor casing.

Conduit is used at room temperature. For whatever reason it might be pressure-rated, it would be at (or near) room temperature.

Metals get soft quickly when heated and their structural properties ('allowables,' in engineer-speak) go away in a hurry. Aluminum will not only weaken, but will MELT at the temperatures reached in the combustion chamber. Do not attempt metal motor casings, especially if this is one of your first steps into EX-type rocketry.

There is a reason that paper casings are used for millions of small motors. You really need to pay attention to those lessons.

Sorry if this sounds like a lecture (I guess it is one, anyway) but metal casings really are a very very bad idea.
 

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