18 replies to this topic

[pendulum]

Hi

I made my first ever batch of blackpowder today. I tested it by burning it in a straight line, and it burnt quite enthusiastically and quick. I put a few grams inside a banger casing and lit the fuse, and it did produce a "pop" and pushed out a glued-in-place endcap. So it's not terrible BP.

Do you think this will be good enough for my rocket motor? The charcoal used was bought from a petshop but the other 2 chemicals were good quality. I ball milled the charcoal and the sulphur was already very fine. The kno3 was quite big particle size and could've done with milling.

Do you think I would need to mill all 3 together to make good BP or is what I have sufficient? I just mixed all 3 chemicals together by gentle shaking. I know the obvious answer is 'test it' but I don't have the bentonite to make the nozzle nor the rocket ramming kit yet so I can't.

Is willow charcoal necessary for rocket motors? It's quite expensive from eBay etc but I guess it would last a long time.

[fishy1]

When I mix coffee grinder (lumpy) BBQ charcoal with kno3 in pellets and sulphur and shake them together, with reasonable confinement I can make a loud "bang" rather than just a "pop". JUst because it works in a banger doesn't mean it's fast.

Ball milled BPwill make your motors more reliable, but i've made rockets to a very similar method to what you do and had them shoot up. Suggest you at least ball mill the kno3 on it's own and the charcoal/sulphur together.

Good quality charcoal isn't needed to make rockets, in many cases you need to slow down fast BP to make rockets.

Willow charcoal definately isn't needed to make rocket motors.

[aquarius]

What you have on your hands is "meal", not real BP as I see it.
You should ballmill all three ingredients with a non-sparkling media, like lead.
Moisten it and granulate it with a sieve and dry. There are countless guides about this out there. Now you should have a better product.

You can use your meal as it is (probably) in rockets, but the effect might not be all that great.
You say nothing about your ratio, but for starters 60:30:10 is a good choice.
Conserning bentonite and clay plugs, buy cheap kitty-litter containing bentonite. And read a lot about the subject. You will need to experiment a bit on your own with nozzleopening, corelength, ID etc.
Again, do a search on the web and it will answer many of your future questions.

[pendulum]

Thanks for the replies.

It made quite a loud pop, but I think it would have gone bang if I hadn't been in such a hurry and had let the glue dry properly. I've made another one and this time will leave the glue to dry for an hour and see if it goes bang (just out of interest).

The ratio I used was 75 : 15 : 10.

Tomorrow I'll make some more (will try the 60:30:10 ratio) and ball mill all 3 chemicals together. I have done some reading and I gather that all I need to do is have the ball mill outside (no problem), use non-sparking media (I have brass) and keep the composition slightly damp by spraying it with water every now and again.

Btw, I've ordered the bentonite already so may as well wait for it. I hope it all comes soon

[BrightStar]

Pendulum, You will be in no doubt when you have real BP.... just place a teaspoon full on a sheet of ordinary A4 copy paper and touch with a splint. If it vanishes in a puff of smoke (hardly any sparks) without igniting the paper then you have it... almost any grade of BP will burst a tube with a 'phutt' - no indication of quality unfortunately.

Testing in end burning rockets, my fastest 75:15:10 willow is hopeless - it will always CATO a few metres off the ground. 75:15:10 BP made with 'garden charcoal chips' has the opposite effect - a large cloud of smoke, never leaving the pad. For end burners, slowing down my fast willow BP with extra charcoal often works.

Core burning motors should be much more tolerant of variations in your BP mix, but you will have to run a few tests to 'dial it in'. You may even be able to use 'green mix' instead of fully incorporated BP.

Edited by BrightStar, 04 October 2006 - 09:17 PM.

[ActionTekJackson]

What you have on your hands is "meal", not real BP as I see it.
You should ballmill all three ingredients with a non-sparkling media, like lead.
Moisten it and granulate it with a sieve and dry. There are countless guides about this out there. Now you should have a better product.

You can use your meal as it is (probably) in rockets, but the effect might not be all that great.
You say nothing about your ratio, but for starters 60:30:10 is a good choice.
Conserning bentonite and clay plugs, buy cheap kitty-litter containing bentonite. And read a lot about the subject. You will need to experiment a bit on your own with nozzleopening, corelength, ID etc.
Again, do a search on the web and it will answer many of your future questions.

If I read this right you're thinking you're gonna wet the meal whilst inside your mill? This would NOT be a good idea.... unless you want a huge mess. The meal will merely stick to your brass media, while it does make good bp, its a royal pain to get off the media and out of the mill. Mill it for however long works for your rockets (this means you will have to test), unfortunately BP is never exactly the same, so your BP is particular to you, thus the need for experimentation. The only REAL need to wet BP is when making lift powder for Artillery shells. I can make BP that will CATO every damn time without any wetting process at all, however, like I said, it's particular to its owner *kinda ;-)*. So if you need it faster and more milling is making an effect, then wet it untill a homogenous clumpy consistency, slightly more dry than playdough, and press it through a kitchen style strainer. Let the granules dry and harden, this will increase the burn rate of your BP tremendously, but do this only if you HAVE to, otherwise its a waste of time, unless of course you want lift power...

[BrightStar]

If I read this right you're thinking you're gonna wet the meal whilst inside your mill? This would NOT be a good idea.... unless you want a huge mess. The meal will merely stick to your brass media, while it does make good bp, its a royal pain to get off the media and out of the mill.

We are getting a bit off topic here, but I must admit I add some moisture every time I mill BP. Not enough to make a mess, but 1 or 2% of water and IPA sprayed into the jar to start off with reduces dust, prevents static buildup, better incorporates the KNO3 in Tigertail / Chrys 6 charcoal mixes and (in my mind at least) might reduce the chance of that one spark.... I guess we all have our strange rituals here

As mentioned above though, a good green mix will be fine for core-burning rockets and safer to mill. See here for instructions on good mixes:

Pyrotooling - Mixing the comp

Edited by BrightStar, 05 October 2006 - 07:04 AM.

[aquarius]

My opinion on wetting the BP has two sides:
1 - The comp will have better mix, Alan Yates has written a good review on this. Look up his page for a better understanding.
2 - Loading of the comp is easier and not so messy. Using granulated BP (or RP - Rocket Propellant) will save you the hassle of all the dust with airfloat BP.

I use a mix 70-20-10 RP, milled, wetted, granulated and dried without dextrin. To this I add 10 % coarse charcoal and shake it in before use for a better tail.

You will probably find as many opinions as users on this theme, what you find to work for you is up to you.

"if it ain't broken, don't fix it"

Edited by aquarius, 05 October 2006 - 09:16 AM.

[ActionTekJackson]

Lol, well, wetting does have its upsides.... guess I'm just too lazy to do it when I don't have to

[pendulum]

Success!

The first rocket I made didn't get off the ground , but the second went about 15-20 metres up and left a lovely trail, and it flew pretty much straight up.

I'll try to find it in the morning.

I used Tesco's kitty litter for the nozzle material and it did work, although I think it was to blame for the first rocket's failure, it was quite hard to get it to go solid (it always wants to just crumble back in to powder).

[aquarius]

Try to grind the kitty litter into fine powder, or at least sieve it before ramming.

When I ram nozzles I use as much force as possible without damaging the casing.
A matter of trial & error, but when you find "your way", it works like a charm!

What's the dimmentions on your device?
ID, corelength, nozzle- and corediam and so fourth.

[pendulum]

My Inoxia order has come, and now I have proper bentonite, the kitty litter did work but it was very hard to break down to a fine powder (I think it would need to be ball milled/pestle). The Inoxia stuff is way easier to use as it comes really really fine already.

My rockets are 1/2" ID. I use the 1/2" ID rocket tooling set from pyrotools.com. The tubes are from Inoxia and they have a 3mm wall.

Well, I made 2 today and BOTH blew up on take off. Hell of a bang. I tried adding loads more charcoal to the second one to slow down the burnrate but it still blew up! The first rocket climbed about half a metre before blowing up, the second one about 2 metres.

I am thinking that it might be the tubes - perhaps 3mm is not big enough and makes it prone to explode. I suppose I could roll some kraft paper around it to increase the tube's strength?

Might try that tomorrow.

Edited by pendulum, 14 October 2006 - 12:17 PM.

[BlackSky]

My Inoxia order has come, and now I have proper bentonite, the kitty litter did work but it was very hard to break down to a fine powder (I think it would need to be ball milled/pestle). The Inoxia stuff is way easier to use as it comes really really fine already.

My rockets are 1/2" ID. I use the 1/2" ID rocket tooling set from pyrotools.com. The tubes are from Inoxia and they have a 3mm wall.

Well, I made 2 today and BOTH blew up on take off. Hell of a bang. I tried adding loads more charcoal to the second one to slow down the burnrate but it still blew up! The first rocket climbed about half a metre before blowing up, the second one about 2 metres.

I am thinking that it might be the tubes - perhaps 3mm is not big enough and makes it prone to explode. I suppose I could roll some kraft paper around it to increase the tube's strength?

Might try that tomorrow.

I think you have to press them more. Do you use press method or ramming ?
I was facing the same thing before but when I made my press more than 3 tons it becomes OK .
Currently I use 5 tons press. But I used PVC pipes not kraft papers tubes.
My BP is 6:3:1/PN:C:S ratio.

Regards
BS

Edited by BlackSky, 15 October 2006 - 06:43 PM.

[pendulum]

I use the ramming method. I do ram it all in pretty hard. I think that it was the BP not being slow enough (which is what some people above told me). I added even more charcoal to it, and now I've flown 2 rockets since without them exploding on take-off.

The next time I make BP I will make it 60:30:10 or maybe even a bit more charcoal than that.

Thanks,

Oh, another reason that could possibly have contributed was the way I secured the fuse so that it wouldn't fall out of the core. I could have secured it in place a bit too much meaning that when the rocket core started burning, the nozzle was still clogged up with fuse. Or it might have been too tight a fit making the BP confine and explode. I doubt it but it is possible. I'm more careful now anyway, so if it was that, it won't happen again.

Edited by pendulum, 15 October 2006 - 06:57 PM.

[BlackSky]

Oh, another reason that could possibly have contributed was the way I secured the fuse so that it wouldn't fall out of the core. I could have secured it in place a bit too much meaning that when the rocket core started burning, the nozzle was still clogged up with fuse. Or it might have been too tight a fit making the BP confine and explode. I doubt it but it is possible. I'm more careful now anyway, so if it was that, it won't happen again.

Yes. Also the fuse has an effect . I remember that happend to me too, specially when you have a fast burning BP or a small nozzle with a large fuse diameter.

Anyway , It seems that you are smart to discover these things by yourself.