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Ez2cDave

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quickburst

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I have a theory that this would be far more likely to occur in a Composite motor than a BP motor.

This is due to the fact that the Convergent Section of the Nozzle is exposed in a Composite motor and could allow something to "cock sideways", momentarily plugging or restricting the Nozzle, resulting in over-pressurization.

In a BP motor, the Convergent Section is not exposed until after the motor is ignited and burning.

Dave F.
David,

If using "home brew BP", how fine should the particles be ?

Dave
Just imagine 2F Black Powder try to match that. I suppose there is an expected grain size chart somewhere. It will most likely your Home Brew will be slower than the commercial offerings. If you have smaller grains you powder should burn faster. That should narrow the gap down a bit.

The best I ever produced was using the alcohol method, and you may know what I mean. I hesitate to describe that, fear of someone getting hurt.
 

jbr

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I use the alcohol method and get real close to commercial
lobbed many 4" shells, and a few 6" ones
messed with BP rockets some, found they make better booms than whoosh which is good when you want that also
my BP is all I use for ejection now, around $3 a pound
 

heada

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I get real close to commercial. I'm water based rather than alcohol. Also make my own airfloat from cedar. Initially it's a 1f size, wait until it starts to harden and then re-divide down to 4f and fully dry.

This past summer I did 300x 1.75" in 6 racks, 100x 2" in 2 racks, 100x 3" in 5 racks, 20x 4" in 4 racks and 20x 6" individually. Ended up making over 50lbs of BP. Gonna scale it back some next year.
 

Ez2cDave

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The best I ever produced was using the alcohol method, and you may know what I mean. I hesitate to describe that, fear of someone getting hurt.
Yes, I know the method . . . No need to describe it.

Dave F.
 

quickburst

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I have used the alcohol method as well. I'm guessing that I just happen to suck at it. I know a guy that presses his in a hydraulic press, he claims it's the only way to go. I think I'll pass on that.
 

prfesser

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The type of charcoal makes a HUGE difference in the speed of BP. Charcoal made from willow, paulownia, or grapevine can give BP that will exceed the speed of commercial BP. Saw it demonstrated several times at PGI. "Pyro golf" -- launch a golf ball into the air with a set amount of 2F screened BP. Most of the homemade ones exceeded the hang time of Goex. In fact they had to reduce the amount used because golf balls were lost more than once.

I think most of them used a ball mill, but the alcohol method should see an improvement in speed as well.

Best -- Terry
 

jbr

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