28 replies to this topic

[CCH Concepts]

thanks for all the help guys.

I've now got the grain size right, the shell tighter fitting and doubled the 6" tube to 12", also the new milling media helped alot.

I'm using a 1" tube and with 18 grams of BP i have no idea how far it went but i didn't hear it land.

and with 10g of BP, throw a 10g charge a good 50 meters up, would have gone further but the fuse was only about a seconds worth.

[seymour]

It's always a good feeling when things work!

It does sound like it needs some more improvement though.

[CCH Concepts]

i have no doubt, i just brought a electric hob for my workshop so i can try the CIA method in a more controlled area than a kitchen, lol

[digger]

i have no doubt, i just brought a electric hob for my workshop so i can try the CIA method in a more controlled area than a kitchen, lol

If you get your mill working correctly you will get much better BP than by the CIA method (although it can make reasonable BP).

Get the next couple of Kg of media for your mill. You won't be disappointed.

When you get you BP sorted you will be using no more than 2 grams to loft your 10 gram shell (maybe even less if you get it perfected, you should be able to get down to 1.5g for 10 grams).

D

Edited by digger, 07 September 2009 - 08:49 PM.

[CCH Concepts]

really thats impressive. the jar I'm using is only about 500ml. i couldn't even fit 1kg of media in it. i filled to 2/3 full and ran it for 3 hours to get the results i got. i will run t over night this weekend and see how i do then. another thing to take into account is it had only have a few hours drying time and wasn't completely dry, i just got impatient.

[digger]

really thats impressive. the jar I'm using is only about 500ml. i couldn't even fit 1kg of media in it. i filled to 2/3 full and ran it for 3 hours to get the results i got. i will run t over night this weekend and see how i do then. another thing to take into account is it had only have a few hours drying time and wasn't completely dry, i just got impatient.

I thought you were refering to your 3 litre jar.

In the days that I was experimenting I would lift a 12 gram 15mm comet with 1.2g of BP. I would guess that this is not that unusal.

I was at a competition earlier in the year and some people were lofting a 130 gram cricket ball out of a 3" mortar with a flight time of around 12 - 15 seconds with 8 grams of BP (not even a very tight fit).

[Vic]

i will run t over night this weekend and see how i do then. another thing to take into account is it had only have a few hours drying time and wasn't completely dry, i just got impatient.

You wont to at lest allow overnight drying in a warm dry place, mill your BP until it looks Gray in colour and maybe starts clumping up in the mill use the minimum amount of h20 and binder just enough to hold the grains together when you rice through a screen.

[cooperman435]

CCH please consider the impression your giving off on the forum still. Impatience is not a thing we can have in this hobby. Digger is right, ballmilling will offer far better results than your saying your BP offers currently but you still need to establish basic sense with these dangerous things your experimenting with.

I have no doubt that BP could be made by hand that would perform better than is required to loft a 10g projectile using 18g.


What concerns me more is that with this poor performing BP which you are doing the correct safe thing by testing and slowly improving your launching live shells. YOU SHOULDNT BE. just launch dummy or inert projectiles to be safe. PLEASE

[CCH Concepts]

point taken with impatience being inappropriate.
the projectiles for the first few lunches had no explosive in them, just hot glue to add weight. the first test had 18g bearing mind the effectiveness of my previous BP this was alot more than require because i hadn't been getting a very good result. when this test produced a result more than required i reduced down to 10 grams. the only charge i tested with explosive in it was a small 1" plastic shell with 1g of BP and a star. nothing complicated just so i could test my priming and height.

my next tests will be to find the min amount of BP to get a repeatable result with the quality of BP i am getting, while of course improving my BP.

[digger]

the projectiles for the first few lunches had no explosive in them

Just a nice ham sandwich?

[CCH Concepts]

random, but ok!!!

[cooperman435]

1 make your bp good
2 test it
3 make it better
4 test it
5 if your satisfied its ok then make some more and test it if its still not ok refer to stage stage 3 again
6 test heights with dummy shells
7 test a live shell

THATS THE ORDER ITS DONE IN.

[CCH Concepts]

Whats a good bench mark test to grade my bp.

[digger]

random, but ok!!!

A bit like your spelling. I assume you meant launches and not lunches, hence the ham sandwich comment.

[TCblastmaster]

I have had some very good results with the CIA method but usually ball mill the C and S beforehand- otherwise you get solid lumps of sulphur in the finished product. However, using the CIA method and then ball milling the dried granules produces a much faster powder. Never compared it to the purely ball milled variety because one tends to stick with what has previously worked well.

In my experience the effectiveness of the CIA method depends on a number of things; ensuring that just enough water is present to keep all the KNO3 in solution prior to adding the alcohol - difficult when so much of the water evaporates during heating large batches safely and a large proportion may no longer be in solution (showing up as large crystals on drying and poor performance)and adding the correct amount of chilled alcohol to rapidly and completely precipitate the KNO3 -some of which could be lost when wringing out the ball of BP if too much water has been added or too little alcohol. Clearly the proportions of chemicals in the composition can change in many ways. Get it spot on and you'll have good lift powder with rather delicate grains (when grated through a screen). I have also found the lift made by this method to be very hygroscopic- what starts off as brilliant lift can be rendered useless by atmospheric moisture- purely anecdotal but I have experienced it, much to my embarrassment.

Ball milling is therefore essential, whatever method you use. Producing excellent BP is the Holy Grail of pyro and often a closely guarded secret.

TC