nozzle material

[BigtonyICU]

I've been building model rockets for about 5 years and now I've decided to me not only the body the the motor also the main problem I'm having I's finding what material I can mold to nozzle out of, the motor dimention is 4'' diametre and 10.5" long my fuel is Potassium chlorate XX% sugar XX% and sulfur XX% epoxy XX% (binder) [total fuel weight 18 Oz].

I was thinking plaster or ''Durham's rock hard water putty'' (or even a mix of both). I'm affraid of the nozzle cracking under the pressure

If anyone has any other suggestion please respond.

waiting for responce TONY

fuel ratio's edited by moderator

 

[marvSRG]

Tony,

Welcome to TRF! Glad to see more and more new people like yourself...and we especially like to see great projects. But I'm sorry to tell you that we don't discuss EX in this forum for various reasons....it needs its own category Please do not think that we don't want you in here because you are completely welcome and there are tons of knowlegable people to talk with and get help with. But EX motors are one of the things we do not discuss. I am also a member of the www.rocketryonline.com forum and they have a amateur/experimental section of their forum that is the perfect place for this post! But since I am talking...it does sound like quite a hefty motor...but may I reccomend something? It's obvious that you are doing a variant of the common "sugar" or "candy" propellant...the only really big difference is that you are using Potassium chlorate and that's NASTY stuff...you don't want to mix chlorates in with rocket propellant. You may be getting it confused with Potassium per chlorate...but that's not that much better (there's only one reasonable formula that I know for that). For this type of propelant you need Potassium nitrate which is commonly used in the sugar propellants...but also, sugar is not only the fuel, but the binder in this type of propellant (it's a process of melting the sugar and then mixing in all of the other chemicals in it). You don't need the epoxy....however some people are working on formulas that replace the sugar with epoxy and other chemicals, but epoxy and sugar usually do not go together. It's one or the other. Some epoxy propellant formulas do have a VERY small amount of sugar in them for fuel though...but the general rule is either sugar for fuel and binder OR epoxy+some other things you'll have to find out for fuel and binder. Try www.nakka-rocketry.net for TONS of info on sugar and epoxy based formulas, motors, and A LOT of other excellent information. Lastly I noticed that you are jumping right up to the big 4" motor....I reccomend getting it down with some small test motors first and then moving on up (aw darn...gotta make more motors). Also, the Durhams would do OK in small motor nozzles, but for 4" you're looking at phenolic or graphite nozzles. Well I hope the info helped and try www.nakka-rocketry.net, and this post would be great for the www.rocketryonline.com amateur/experimental forum. Hope that helped! And once again welcome to TRF...now bring on the pics and the questions about your rockets themselves and certified motors!

 

[Ryan S.]

Water Putty works. www.inverseengineering.com. Find a better way to secure it. You can also use a type of cement. Nakka talks about that. other materials are graphite and I think Mcmaster Carr sells graphite nozzles and phenolic nozzles for single use motors

 

[powderburner]

Originally posted by BigtonyICU
my fuel is Potassium chlorate, sugar, and sulfur, epoxy . . .

Hi BigTony,
Welcome to TRF! We would like to help you as much as we can, but this kind of stuff is a little beyond where we walk.
I can tell you this: I have extensive personal experience with K chlorate, K perchlorate, K permanganate, Na chlorate, Na perchlorate, fuels ranging from powdered Zn to Al to Mg and even powdered bronze (what can I say, I was a dangerous kid). This stuff can kill you. These reagents are exactly the WRONG kind of stuff to be using for slow, consistent, controlled burns (the kind you want inside a rocket motor).
There is lots of info on the net for sugar motors, if you must build your own you should start there. Nakka can give you lots of guidance too.
This whole issue makes me wonder: what does the ICU stand for in your 'tag'? Are you already planning a stay in the intensive care unit?