black powder

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bocochoco
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black powder

Postby bocochoco » Thu Aug 06, 2009 8:40 pm UTC

I'm sure that I'm going to get in trouble for this, but why not.

I've made powder before from S, KNO3, and charcoal. It works well. I heard from a friend that you can make the same thing using sugar instead of sulfur. Is this true? I don't see how sugar can be a substitute for sulfur.

Let me make you aware that I'm not using this stuff for illegal purposes, I use it in making engines for model rockets. I've noticed that different compositions of the fuel have different results in thrust and height/distance.

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Re: black powder

Postby Seraph » Thu Aug 06, 2009 9:25 pm UTC

KNO3 is a very good oxidizer. Combining it with a good fuel can result in something that burns rapidly or explodes. Sugar is probably not the best fuel, but it'll probably give you a good burn at least.

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Re: black powder

Postby Technical Ben » Thu Aug 06, 2009 9:54 pm UTC

I do remember it being said that amateur rockets can be made with sugar... I learnt everything from TV.



(Sorry for the random google search, but they were all I could find on the subject...) [edit] Oh, and Youtube has vids of the sugar rockets too
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breintje
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Re: black powder

Postby breintje » Fri Aug 07, 2009 10:30 am UTC

I personally never tried kno3 + sugar + charcoal, but kno3 + sugar does burn quite neatly. It is in no way equal or comparable to blackpowder though. It is 1) white, 2) gives of a LOT of smoke, 3) leaves annoying residue and 4) is quite a bitch to light on fire. Where blackpowder burns quick and flashy, even in small amounts, is it nigh impossible to light a small quantity of this stuff. It does sparkle and fizzle a bit if you place some of it in a flame on a scoopula. It will react quite violently once you take a larger quantity of it, say, >5 grammes. Also, the reaction is facilitated by pressure, with a good nozzle only some 25 grams compacted in a tube can lift a nice rocket. Without nozzle you get a slow burning smokebomb.
So, if you want a smoke bomb or rocket, you can use that, for other tasks (explosions f.i.) use other chemicals. I do use blackpowder to prime the engines though, because of its superior burn rate and inflammability, but not for the engines themselves, because they would probably explode during making.

Sugar, is in no way a substitute for sulfur. It's all just about the fact that pretty much any hydrocarbon or other flammable substance will burn violently with potassium nitrate. And, if not, at least with Ammonium nitrate.
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Minerva
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Re: black powder

Postby Minerva » Fri Aug 07, 2009 10:35 am UTC

Sugar(s) will certainly burn violently when finely powdered and combined with a fine powder of [insert your favorite oxidizer here, nitrate, permanganate, chlorate, etc.]
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Re: black powder

Postby Tass » Fri Aug 07, 2009 11:24 am UTC

Sugar can substitute the charcoal, not the sulphur. It will work less well, and give more smoke, but should work.

The sulphur is actually not a fuel but an oxidizing agent in black powder. It is used because potassium has a much higher affinity for sulphur than it has for oxygen. It therefore give most energy to have nitrate to supply oxygen to the carbon, and sulphur to replace the nitrate to satisfy the potassium.

The reaction can be pretty well simplified as such:

2KNO3 + S + 3C -> 3CO2 + K2S + N2

Of course a lot of other stuff happens to, but this is the main part. If you sum up the molar masses you will find that the proportions matches most gunpowder recipes rather closely. If the sulphur was burning to SO2 or SO3 then you would need a lot more nitrate.

You can of course make a pyrotechnic mixture of almost any fuel (sugar, coal, magnisium, aluminium...) and oxidizer (nitrate, perchlorate, permanganate...) but gunpowder has retained popularity over the years because of a combination of affordability and effectivity.

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Re: black powder

Postby bocochoco » Fri Aug 07, 2009 8:54 pm UTC

The main reason why I ask is because I have recently run out of sulfur, and am looking for a substitute since I can't remember where I got the stuff. I normally make it in small amounts using a mortar pestle since I lack a ball mill. The charcoal is easy to obtain, and I got the potassium nitrate from ebay, but the sulfur still eludes me. I was using 75g KNO3 : 15g charcoal : 10g sulfur, but I ran out of sulfur and am also running low on KNO3. If there is a good supplier to acquire the chemicals from, please enlighten me.
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Re: black powder

Postby Tass » Sat Aug 08, 2009 12:01 pm UTC

If you had no sulphur you would have to use more saltpeter. If you are generally running out of oxidizers then I can't help you. I don't know about suppliers where you live. I do have 7kg of saltpeter my self, but it's in Denmark.

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Re: black powder

Postby PM 2Ring » Sat Aug 08, 2009 4:25 pm UTC

Sulfur powder is traditionally used as an insecticide on some vegetable crops.

Sugar burns easily if you add a little ash to it. An old party trick is to rub a little cigarette ash onto a sugar cube and then set it alight.

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Re: black powder

Postby Tass » Sun Aug 09, 2009 9:15 am UTC

PM 2Ring wrote:Sugar burns easily if you add a little ash to it. An old party trick is to rub a little cigarette ash onto a sugar cube and then set it alight.


Cool, I didn't know that. How does it work?

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Re: black powder

Postby bocochoco » Sun Aug 09, 2009 4:38 pm UTC

So there is no reasonably priced internet supplier for saltpeter or sulfur?

Yes, how does the ash + sugar work? Sounds neat
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Re: black powder

Postby heydonms » Mon Aug 10, 2009 4:33 am UTC

Sulfur in black powder is there to lower the ignition temperature and produce slightly more gas, it isn't essential. There is such a thing as sulfurless black powder, just KNO3 and charcoal, it used to be used in pyrotechnic devices that contained chlorates (and I believe some people used it in BP firearms to avoid the sulfur smell). Now that chlorates are becoming less common in pyrotechnics sulfurless is starting to become a bit rare.

The the sugar based rocket propellant is often called rcandy. Do a search for James 'Jimmy' Yawn and Richard Nakka, both have done a fair bit of research on sugar rockets and put up a whole heap of useful information.

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bocochoco
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Re: black powder

Postby bocochoco » Mon Aug 10, 2009 1:15 pm UTC

In my case temperature doesn't really matter all that much, just thrust. If sulfurless black powder can put off enough thrust to shoot a rocket up that would probably work just fine.

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Re: black powder

Postby PM 2Ring » Mon Aug 10, 2009 2:26 pm UTC

bocochoco wrote:Yes, how does the ash + sugar work? Sounds neat

I was taught that the ash acts as a catalyst, but I don't know the details. And Googling hasn't yielded any more info, except to suggest that it's a catalytic effect of some metallic ions in the ash. I suspect there is also some effect from the ash adsorbing onto the sugar, changing its surface properties, both physical & chemical.

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Kow
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Re: black powder

Postby Kow » Mon Aug 10, 2009 4:35 pm UTC

I hate to be an advertiser, but I frequent a site that has forums that might be of assistance to you:

http://www.zoklet.net/bbs/forumdisplay.php?f=90
http://www.zoklet.net/bbs/forumdisplay.php?f=51

The first link being to the more explosives side and the second to the more chemistry side of your request. The people there seem to know their stuff and could probably help you.

Edit: Searching the latter forum probably wont yield any results, but the former might. Regardless, a thread can be made (though I don't recommend both at once)
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Re: black powder

Postby bocochoco » Mon Aug 10, 2009 9:52 pm UTC

Sounds like a good place to go. After class tonight I'll check it out and hopefully someone could help me out. We are trying to power a rather large rocket and the normal engines you get at hobby shops are far too small. We tried using 3 of them before and it barely got enough lift to go. I was wondering if an explosive charge underneath the rocket would help give it some initial inertia and at the same time ignite the engine in the rocket itself, might help get it going better. Black powder seems like the best bet to use for this application.
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heydonms
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Re: black powder

Postby heydonms » Tue Aug 11, 2009 12:52 am UTC

Whether or not a pile of BP under the engine will ignite the motors will depend largely on the size of the nozzle. On smaller motors it certainly doesn't work, on larger ones you might have a chance, but I would suggest putting some black match up through the nozzle to improve the odds.

Having said that, a pile of BP under the rocket is unlikely to provide any lift. You would need to load the rocket into a mortar to confine the gases. All of which is really unnecessary, it is quite possible to make an effective BP or rcandy engine which will lift a significant mass. Unless you are building your rockets out of concrete or something there is no reason that the motor alone couldn't lift it.

Are you making end burners or core burners? What I/D tubing are you using for motors? Are you making your own nozzles or refilling bought motors? How much does the rocket weigh?

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bocochoco
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Re: black powder

Postby bocochoco » Tue Aug 11, 2009 1:58 am UTC

heydonms wrote:Whether or not a pile of BP under the engine will ignite the motors will depend largely on the size of the nozzle. On smaller motors it certainly doesn't work, on larger ones you might have a chance, but I would suggest putting some black match up through the nozzle to improve the odds.

Having said that, a pile of BP under the rocket is unlikely to provide any lift. You would need to load the rocket into a mortar to confine the gases. All of which is really unnecessary, it is quite possible to make an effective BP or rcandy engine which will lift a significant mass. Unless you are building your rockets out of concrete or something there is no reason that the motor alone couldn't lift it.

Are you making end burners or core burners? What I/D tubing are you using for motors? Are you making your own nozzles or refilling bought motors? How much does the rocket weigh?



I meant that I would use it in a mortar type, not a pile underneath it.

I am making core burners to propel the rocket. The Tubing is about 2.15" ID for the motors. The nozzles I have made are de laval modeled made out of a weird yellow clay I got from my school. The rocket weighs 19.4oz nose to tail without engines and is about 2 feet long.
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Re: black powder

Postby heydonms » Tue Aug 11, 2009 2:37 am UTC

One problem with loading a rocket into a mortar is that you need to keep the fins out of the way which means either mounting them half way up, spring loading them, or using a spin stabilized design. I don't like any of those ideas, but I guess that is largely personal preference. Also your rocket will get *covered* in powder residue and there is a reasonable chance you will damage it while you work out the details like lift:weight ratios, ideal grain size, etc.

At a glance, your dimensions and weights don't appear too extreme (although it does sound a little heavy for something 2' long, what is it made out of?) I don't see why a core burner couldn't lift that without needing to resort to mortars.

Have you inspected the nozzles after use? Are they eroding? If so, try rammed bentonite (with grog and paraffin wax if you can find them, skylighter has a blog post with ratios and such).

Do you mill your BP? (If not, and you decide to start, strap a few engines to sticks and test them out before you use them in your rocket. Catos are quite likely)

If all else fails, you can always upgrade to whistle mix (do a lot of reading before you mess with it, it is far more sensitive than BP).

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Re: black powder

Postby opsomath » Tue Aug 11, 2009 2:19 pm UTC

DEAR EVERYBODY. Please be VERY careful if you use any chlorates in anything, as has been suggested in this thread. They form very unstable mixtures in the presence of traces of acid, which is present in all sulfur as well as other things.

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Re: black powder

Postby bocochoco » Tue Aug 11, 2009 8:42 pm UTC

heydonms wrote:One problem with loading a rocket into a mortar is that you need to keep the fins out of the way which means either mounting them half way up, spring loading them, or using a spin stabilized design. I don't like any of those ideas, but I guess that is largely personal preference. Also your rocket will get *covered* in powder residue and there is a reasonable chance you will damage it while you work out the details like lift:weight ratios, ideal grain size, etc.

At a glance, your dimensions and weights don't appear too extreme (although it does sound a little heavy for something 2' long, what is it made out of?) I don't see why a core burner couldn't lift that without needing to resort to mortars.

Have you inspected the nozzles after use? Are they eroding? If so, try rammed bentonite (with grog and paraffin wax if you can find them, skylighter has a blog post with ratios and such).

Do you mill your BP? (If not, and you decide to start, strap a few engines to sticks and test them out before you use them in your rocket. Catos are quite likely)

If all else fails, you can always upgrade to whistle mix (do a lot of reading before you mess with it, it is far more sensitive than BP).


It's made of wood. Probably not the best thing to use, but it works.. sorta. I've been milling my powder in a mortar & pestle, which is probably dangerous to do. And strapping rockets to a stick was the worst thing I've ever done. Stupid thing took off and flew into my neighbors house, left really nice burn marks in their carpet in the process. Also tried tying one to a string (you can imagine how well that worked), with pretty amusing results. As far as dangerous chlorates go, I've been told to use perchlorate instead of KNO3, but skylighter won't sell it to me nor does it seem to be available nearby. My area is pretty dead in terms of intelligence and places to go for things that require said intelligence, so online retailers are pretty much the only place I have to go to acquire chemicals. My nozzles are usually a bit wider than they were when I made them, but for the most part they stay intact.
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Re: black powder

Postby heydonms » Wed Aug 12, 2009 12:27 am UTC

Um...no one suggested using chlorates, I said their use was declining and with it the need for sulfurless powder. The only compositions that have been mentioned are BP, rcandy and whistle, which are all nitrate or perchlorate based.

A mortar and pestle can make decent BP, but it is slow going. A good mill will make a batch in about 3-5 hours so unless you are grinding by hand for several hours you probably aren't getting the best out of your powder but as I mentioned before, be careful, core burners made from good milled powder tend to cato.

Strapping engines to sticks should work, it is how pretty much all pyrotechnic rockets are guided (and most of them are *really* top heavy), but it is always a good idea to launch in a wide open space.

I don't really know many US suppliers, but there are quite a few out there. Skylighter doesn't like selling perc to people they haven't dealt with because they are worried that some idiot will use it to make flash and blow himself up (resulting in bad press for pyrotechnics in general). If you can convince them that you aren't doing anything stupid they might be more helpful (but still overpriced). What area are you in?

Even a relatively small amount of nozzle erosion can reduce lift by a fair bit. Try the skylighter nozzle mix.

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Re: black powder

Postby bocochoco » Wed Aug 12, 2009 6:00 am UTC

heydonms wrote:Um...no one suggested using chlorates, I said their use was declining and with it the need for sulfurless powder. The only compositions that have been mentioned are BP, rcandy and whistle, which are all nitrate or perchlorate based.

A mortar and pestle can make decent BP, but it is slow going. A good mill will make a batch in about 3-5 hours so unless you are grinding by hand for several hours you probably aren't getting the best out of your powder but as I mentioned before, be careful, core burners made from good milled powder tend to cato.

Strapping engines to sticks should work, it is how pretty much all pyrotechnic rockets are guided (and most of them are *really* top heavy), but it is always a good idea to launch in a wide open space.

I don't really know many US suppliers, but there are quite a few out there. Skylighter doesn't like selling perc to people they haven't dealt with because they are worried that some idiot will use it to make flash and blow himself up (resulting in bad press for pyrotechnics in general). If you can convince them that you aren't doing anything stupid they might be more helpful (but still overpriced). What area are you in?

Even a relatively small amount of nozzle erosion can reduce lift by a fair bit. Try the skylighter nozzle mix.



I live in NJ, a big crappy state. Don't come here, you'll hate it. I just discovered unitednuclear, and made an order from them. Prices seem good (maybe a bit high). I also do not have access to a mill, though I could probably build a crappy one.

My friend has started milling a cement mixture to a very fine powder, and is going to make nozzles out of that. Definitely a lot heavier than the clay I've been using, but it won't erode like my nozzles do now.

The problem with the engine on a stick was that it wasn't properly attached to the ground, and being much more heavy on top went on a nice arc right through an open front door. Lucky for me they are in the process of replacing the carpet and didn't make me pay for the damage.

Forgive my ignorance, but what does cato mean? Also, what is "whistle"?

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Re: black powder

Postby heydonms » Wed Aug 12, 2009 6:50 am UTC

If you can get your hands on bentonite (ceramics shops are good for the fine stuff, but even cheap kitty litter will do), give it a go, things like cement and plaster which you need to wet will distort and shrink as they dry and mess with your dimensions. Bentonite is rammed dry and will compact into a nice solid nozzle which wont change it's shape over time.

When I said strap it to a stick, I didn't mean keep it on the ground. The stick is there to balance the engine and keep it flying straight. Much the same as the fins and nosecone and such do on a model rocket, but without the cost if something goes wrong.

Depending on who you ask cato means either "catastrophic failure" or "Catastrophe At Take Off" either way, it is where the gases can't escape fast enough and the engine explodes. If it happens when the motor is in your rocket, it is likely to cause a fair amount of damage.

Whistle is a mixture of potassium perchlorate and sodium benzoate, sodium salicylate, potassium benzoate or potassium salicylate. It can also include petroleum jelly and/or iron oxide as binder and catalyst respectively. It is a significantly more powerful (and more dangerous) propellant than BP, it gets it's name from the noise it makes when made into engines of suitable dimensions.

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Re: black powder

Postby Carnildo » Wed Aug 12, 2009 6:52 am UTC

bocochoco wrote:Forgive my ignorance, but what does cato mean?

"Cato" is "catastrophic failure": the rocket blows up, scattering bits and pieces around at lethal velocities. It's why rocket scientists tend to work from concrete bunkers well away from the launch pad.

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Re: black powder

Postby opsomath » Wed Aug 12, 2009 2:09 pm UTC

Minerva wrote:Sugar(s) will certainly burn violently when finely powdered and combined with a fine powder of [insert your favorite oxidizer here, nitrate, permanganate, chlorate, etc.]


That's the only reason I said that about chlorates. Permanganates have a nasty tendency towards spontaneous ignition, too, especially with sugars. No offense, just trying to keep everyone's fingers on.

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Re: black powder

Postby heydonms » Wed Aug 12, 2009 11:11 pm UTC

Sorry, you are quite right, I missed that.

I would be more worried about permanganate than chlorate, but both should be avoided.

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Re: black powder

Postby meat.paste » Thu Aug 13, 2009 4:30 pm UTC

Perchlorates are quite a bit more reactive than chlorates. The metal salts tend to spontaneously explode. I've made sugar/KClO3 powders before. They burned rapidly with a pretty blue color. BP, by contrast, didn't seem to burn as hot (although it still thermally decomposed a limestone counter-top). I hadn't heard of the whistle mix before. I may have to try it.

Another simple-ish rocket fuel is powdered zinc and sulfur mixed together. The nozzle can clog, though, with the ZnS. Given the rapidity of the reaction, catastrophic pressures can build rapidly in the engine if this occurs.
Huh? What?

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Re: black powder

Postby bocochoco » Fri Aug 14, 2009 2:22 pm UTC

What is this whistler mix that I keep reading about in here?
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Re: black powder

Postby jaap » Fri Aug 14, 2009 2:28 pm UTC

bocochoco wrote:What is this whistler mix that I keep reading about in here?

See heydonms description a few posts up, or see wikipedia.

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Re: black powder

Postby breintje » Fri Aug 14, 2009 8:58 pm UTC

In Europe, where generally all pyro is forbidden you can buy KNO3 at food/spice/additives suppliers, as saltpeter is known as E252, used to preserve meat. The http://www.naturalspices.eu store ships it in 2.5 KG boxes and even 25KG bags, of 99.5% guaranteed purity. I guess that you could search for a similar supplier in the US. Potassium chlorate is probably harder to come by, and although I've played with it at chem lessons, I wouldn't use it for rocket engines. My chem teacher said it'd probably work though.

For nozzles: Yes, bentonite should work, and yes, some cat litter brands are made out of pure bentonite, although there is no guarantee whatsoever that any brand will do. Prepare to end up with a couple of kilo's of worthless junk (unless you actually have a cat). The cat litter I got could be pounded into caps, after grinding the particles with a coffee grinder, but when I drilled it out and tested the rocket this "nozzle" completely disappeared, eroded away in a second or so. Now I use a stuff called Alabastine "All filler". It is used to fill holes in stone/concrete/plasterboard walls, hardens out in about a day if it's not too thick, can be drilled out and doesnt erode noticeably. For the top cap I do use the cat litter stuff, it will hold as long as there is no flow past it, and I don't know how the fuel reacts to hardening filler.

For my engines, I use 17 g of KNO3 mixed with 10 g of powdered sugar, which is pounded into a paper tube with an I.D. of 22 mm and a length of 95 mm. The first 12 mm is the nozzle, and usually there's about 20 mm left for me to make an end cap. Then I drill out a 6 mm hole trough the cement cap and the fuel, to make a burn core and nozzle. I use blackpowder from firecrackers to prime it, and add a standard fuse, with some masking tape to hold it in. As for sticks/fins, my only real fin test failed because that rocket had a too small core, causing it to have a too slow start, and tip over at the end of the launch rod and take off horizontally into the wind. I haven't done a real stick test, although at a static test with a launch rod with a nut on the end the engine ripped it out of the ground and flew quite nicely and stabilized up to some 30-40 metres (over a street with cars parked everywhere, hard metal threaded rod :shock: , scared me to death, thank god no damage). I guess that if you have a stick that is long enough so the COG is below the engine exhaust you will have a stable, vertical flight.
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Re: black powder

Postby heydonms » Sat Aug 15, 2009 2:31 am UTC

I know that Britain doesn't completely ban amateur pyrotechnics, they have a 100g rule or something so there are a few suppliers there. There are also a few other suppliers I have heard being discussed by Europeans, didn't pay much attention at the time so I don't have details :/ I don't know how easy it is to post stuff like that around Europe but I imagine being able to send it by road would make it easier than for someone who has to receive everything by air.

breintje, are you sure your fire crackers are black powder? Is it granulated or fine like flour? Most of the crackers I have seen/heard of are made from flash rather than BP. It will still be a grey/black coloured powder but it is much more sensitive to friction and impact. I guess the fact that it doesn't rip your motor to shreds suggests that it is BP, I just didn't think anyone still made them like that.

If you have access to a lathe, make up a spindle and some rammers (out of non-sparking material) it is much easier than ramming a solid plug and drilling a nozzle and core.

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Re: black powder

Postby breintje » Sat Aug 15, 2009 9:10 am UTC

The firecrackers might just as well contain flash, but since the nozzle is open the rocket can stand the pressure. It is not very friction/impact sensitive, although I haven't tried to pound it, nor will I :wink:. It is a quite fine powder, but burns in my experience slower than whistle.

Yes, we do have a lathe at home, and I have been thinking about making spindle/rammers, although that would give me trouble for casting the nozzles, since that stuff pretty much sticks to everything. If I just cast the nozzle like I do now I'll get trouble drilling it out nice and centered, to fit over the spindle. Perhaps I can coat the spindle and rammer in some kind of lubricant to prevent that sticking, which is worth a try. Won't make any of those though before I've had some good real flights, which is hard because of the lack of space here. When ramming and drilling it is a lot easier to twerk things a little until the result is best.

As far as I know the government here in the Netherlands is not very happy about amateur pyro. I guess that they won't put you in jail for making model rockets though.
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Re: black powder

Postby heydonms » Sat Aug 15, 2009 3:47 pm UTC

If you have a spindle and rammer you can use bentonite for the nozzles since you won't have to drill it. Some people use a silicon lubricant, but I don't think it is really necessary.

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Re: black powder

Postby bocochoco » Mon Aug 17, 2009 1:24 pm UTC

I did a test run this weekend, with some good results. The rocket flew rather well. It even flew the path I wanted it to fly, straight into a lake at full speed. Now I will try to replicate this result a few times before figuring out the rest of this project. Any ideas on how to make a rocket transition from rocket into submarine?
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Re: black powder

Postby Charlie! » Mon Aug 17, 2009 11:18 pm UTC

bocochoco wrote:I did a test run this weekend, with some good results. The rocket flew rather well. It even flew the path I wanted it to fly, straight into a lake at full speed. Now I will try to replicate this result a few times before figuring out the rest of this project. Any ideas on how to make a rocket transition from rocket into submarine?

Lighter than water and you'd have one problem, heavier and you'd have another, and it's going to be screwed up upon impact anyhow. The effort may not be worth it, and it may not even be possible.
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Re: black powder

Postby Tass » Tue Aug 18, 2009 8:08 am UTC

breintje wrote:For my engines, I use 17 g of KNO3 mixed with 10 g of powdered sugar


Sounds like a horribly inefficient mix. Shouldn't you use way more KNO3

By the way, with some care sugar can actually be melted together with KNO3 and the mixture molded, it may ncrease performance, just be carefull and melt a small amount at a time, so it doesn't all blow up in your face.

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bocochoco
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Re: black powder

Postby bocochoco » Tue Aug 18, 2009 1:53 pm UTC

A land-to-lake missile is my ultimate goal. Just needs to work for a neo-pirates vs neo-ninjas battle. They have a boat with cannons.. We have whatever we come up with.


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