KN03/Epoxy

[Tom]

Was playing around with some of the above an hour ago, just mixing the epoxy with potassium nitrate till no more would go into the mix, and then packed it into a tube and left it on top of my halogen light, was cured in 15 mins or so, not bad for 2 hour epoxy : o) Took off the casing, smooth as glass, it was very finely milled KN03. I'll see how it burns tomorrow.

Tom

[Tom]

Burn rate is something like 60 seconds for 15g, both guestimates. I am thinking, a catalysyt, (iron oxide?) to improve the rate. Any thoughts?

[Hank]

Hello- Is that burn rate figured on how this stuff is going to act when its contained? Are you using the binder (epoxy) as a fuel as well?
Powdered Iron or Magnesium (320-1000 screen) seems to be the common fuels.
Hank

[Tom]

No, this was unconfined, but it still needs alot of work, leaving behind the amount of KN03 it does, i'd be afraid of this stuff blocking the nozzle and causing a CATO. However, this is at a small scale, each grain about 10mm dia. Yes, i am using the epoxy as a binder and a fuel, i am somewhat lacking in powdered metals, I am still working on aluminium, Mg would be stupidly hard to find, unless i get bored and place an order in from Lap Pak and pick up some other goodies.

Tom

[Tom]

Haven't blanced it yet, as i don't know the values for epoxy to work on the Stochiometry. Mike K, any word?

Tom

[Hank]

Hello, Tom- I see. You may be able to create your own powder using a file. It's time consuming and does not give a fine mesh. I've used rubber cement as a binder. It's affordable and available.
Please write on this again. Later, Hank

[Ray]

Hi Guys,

I am new to the forum, but I play in rocketry a bunch...I am even making my own motors. I am currently making motors in the "J" impulse range (640NS-1280NS).

I have never made any with KNO3/Epoxy, but Richard Nakka has. His website is here. He has a section devoted to KNO3/epoxy where he details his formulas, and testing. Very informative. It can be found here.

I am more of a cook than a Chef when it comes to making motors, and just follow recipies that others have provided to me. I am using mostly Ammonium Perchlorate/HTPB rubber formulas. I have successfully flown "J" class motors, and am working toward "K's" and "L's".

[Tom]

Jeasus.
Hank, I took your advice on rubber cement, and had I tested a larger quantity, i would have been blown away by the results. After the epoxy/chlorate mixes, i wasn't expecting the speed of this reaction to be that fast, but it got fast enough to spit out chunks of burning propellant and burning magnesium clipping. The mix was made up of Mg clippings, about the same size as fine turnings from a lathe, Potassium chlorate, charcoal and just a dash of Kn03, using vulcanizing rubber cement as a binder. was almost like a eraser, but a lot softer when it hardened, and the test was on chunks a little larger then a pea. I'm impressed.

[Ray]

What you really want is a slower controlled burn. If it is throwing chunks of propellant away from the mass, you'll increase your burning surface area dramatically and the motor will rupture. Burning surface area determines internal pressures in the motor. When surface area increases, so does pressure. The mixes that I am using burn about 5mm/Second at pressure and less than 1mm/second at atmospheric pressure.

Just because it burns fast doesn't mean its a good rocket fuel. The key is the production of gasses. The more gas volume, the better the fuel.

Try the links I posted above. It'll tell you just about everything you want to know about rocket motor design. He has some information there about propellent design and charactarization too.

[Tom]

I know, I know that this isnt a good fuel, I have had first hand experience with CATOs from BP to AP to Nitrous motors. I was merely impressed at the fact that this makes a lot of nice smoke and fire. When it comes to propellant, I follow the instructions given to me, fragmentation grenades aren't what i want to put into something I plan on lobbing into the air.

[Hank]

Hello- Damn, bub, be careful! I have a pile of those old cartrige type flashbulbs which, when removed from their housings, can be wired for a remote test of whatever substance you wish to produce shock and awe.
Just the thing to safely establish burn or, when packed with a suitable amount of smokless powder and wrapped in a slice of cheese and placed next to Mr. Rats hole.......
Hank