Experiments with larger increments for faster rocket-making.

[Ubehage]

I have experimented some with using larger scoops/increments for making core-burner rockets.

Honestly, I got a little tired of ramming down 20-30+ tiny increments for each rocket. So I decided to do some experiments to see how small the increments actually have to be.

 

Let me start with the obvious questions and answers:

- If you use too large increments, the composition will not settle very well.

In best case, it will fall out of your rocket and you can make a new one all over.

In worst case, it will cause the rocket to explode on ignition.

- You cannot use too small increments. The smaller the better, actually.

 

In my experiments, I chose a few different sized spoons (from 1/4 teaspoon to 2 tablespoons) in order to be able to repeat the increment-sizes fairly accurate.

I made some 10mm, 15mm and 19mm core-burners.

All constructions were repeated 5 times, for verification and statistically accuracy.

 

I found out that I can consistently make working rockets by using no less than 5 increments, up to the top of the spindle. For a 19mm CB-rocket, that translates to 5 heaping tablespoons of composition.

 

I hope that some of you may find this information useful and time-saving.

 

EDIT:

I used ballmilled BP 60-30-10 with 0.5% water for all my rockets.

Edited January 5, 2018 by Ubehage

[stix]

Nice work Ubes, but you haven't told us anything about the composition that you have used.

 

May I suggest, if you are into experimenting with various compositions then it may be worth your while to check this out:

https://www.amateurpyro.com/forums/topic/12789-chemistry-experiments-file-stix-pyrocomps-2018-v1zip/

 

The software allows you to create compositions and record all the info. You can make variations and it will be there for your record and then you can post meaningful results.

 

I'm not meaning to belittle your findings, because you have obviously done a lot of work, but without knowing the composition, then we only have a record of your method (this/your method) for pressing "your" fuel - but unfortunately we don't have any other info on which fuel it is.

Edited January 5, 2018 by stix

[Mortartube]

Most hand rammed smaller motors in days of old were rammed in eight increments according to a number of people that have done the job.

[stix]

Most hand rammed smaller motors in days of old were rammed in eight increments according to a number of people that have done the job.

 

What fuel? Please try not to make generic comments.

Edited January 5, 2018 by stix

[Ubehage]

Nice work Ubes, but you haven't told us anything about the composition that you have used.

 

May I suggest, if you are into experimenting with various compositions then it may be worth your while to check this out:

https://www.amateurpyro.com/forums/topic/12789-chemistry-experiments-file-stix-pyrocomps-2018-v1zip/

 

The software allows you to create compositions and record all the info. You can make variations and it will be there for your record and then you can post meaningful results.

 

I'm not meaning to belittle your findings, because you have obviously done a lot of work, but without knowing the composition, then we only have a record of your method (this/your method) for pressing "your" fuel - but unfortunately we don't have any other info on which fuel it is.

Thank you.

I used ballmilled 60-30-10 as fuel.

[stix]

Is that 60% KNO3, 30% SWEAT and 10% CLAY?

 

I'm assuming you are referring to a BP composition, but assumptions can lead to mistakes. You still haven't posted your comp. and the chems used.

Edited January 5, 2018 by stix

[Ubehage]

Is that 60% KNO3, 30% SWEAT and 10% CLAY?

 

I'm assuming you are referring to a BP composition, but assumptions can lead to mistakes. You still haven't posted your comp. and the chems used.

I have edited the original post

60 KNO3

30 Charcoal

10 Sulfur

0.5% H2O

Ballmilled for 4-6 hours. (I made the batch over 2 times; one was ballmilled 4 hours and the other was ballmilled 6 hours)

[stix]

Thanks for posting that Ubes and sorry for the interrogation

 

I reckon that the H2O helps in compacting the fuel? I haven't made a lot of bp myself - I usually concentrate on sugar rockets. BUT, one thing I have noticed when making PB is that a small amount of water, when applied by spritzing with a spritzer thingo (during milling), then the result burns much quicker than if I leave it to dry out for a day or so - When I say quicker, I mean a very noticeable difference. If you haven't tried it, then try it, but be careful.

 

I think I read about this phenomenon on this forum or elsewhere, but it is true. It does seem counter-intuitive, but H2O in minute amounts will and does increase the burn rate of black powder.

 

How long that lasts, I don't know exactly. But if it helps compacting the fuel (which it does) then that is a good thing.

 

I guess the thing to understand/ask after that, is how long does it last that way?

 

[EDIT] My example of this is:

 

After doing a small 50-100gm mix of std bp in a 1ltr ball mill, about halfway through I added a couple of spritzes of H2O, not enough to make it clump up, but just a small amount.

When it was finally milled (approx. 6hrs.) then I did a small test - it burned so quickly I thought "STIX, you magnificent bastard - you've come up with a great blend!".

 

The next day when I tested it again I was surprised that it had slowed down, and the next day even slower until it reached a plateau.

 

I finally realised that the H2O was the culprit, and that also, I wasn't quite as magnificent as I thought I was - although I still reckon I am.

 

ON A VERY VERY SERIOUS NOTE: Slightly whetted black powder can be very dangerous - be careful. From what I've read it's also more prone to static.

Edited January 5, 2018 by stix

[dagabu]

Ubes,

 

In your 19mm ID rocket, how high are the increments once fully rammed/pressed? Historically, 1/2" of the ID in height will give you adequate compression in each increment. 1 ID high will give you a cone of uncompressed powder (sorry stix, fluid dynamics really doesn't car too much what the powder is made from, it's all very close if milled to the same mesh size) 15-20% of the increment height.

 

The only way I have seen this solved is by using near/ultrasonic power settlers under pressure.

[stix]

. . . (sorry stix, fluid dynamics really doesn't car too much what the powder is made from, it's all very close if milled to the same mesh size) . . .

 

Dags, a small amount of H2O DOES increase the burn rate. Do some tests and you will see that this is true.

Edited January 5, 2018 by stix

[dagabu]

 

Dags, a small amount of H2O DOES increase the burn rate. Do some tests and you will see that this is true.

 

But, not the same issue, that is purely mechanical in nature simply because the KNO3 crystals can combine deeper into the charcoal and sulfur to make more of a homogeneous mixture. There is a point of no-return where the water makes no difference and more decreases the burn rate. It also means that you still have a ways to go with your mixture to harness all of its potential.

 

Water (moisture) in small amounts propagates the speed of BP dust by method of super heated steam, if the powder is left to completely dry before lighting the rocket off, some of the power remains from the recrystallization but the steam front disappears. With the expansion ratio of 1:1700. This means that under ideal conditions, 1 part of liquid water expands to 1700 times the volume as steam when boiled. This is by FAR more than BP.

 

"Hyper Milling" that Dave F was working on shows the place where the diminishing returns become evident as the BP if dampened, will not burn faster because a truly homogeneous mixture in theory has been reached.

 

I have been told that the theory of dampened black powder being more susceptible to static is a myth, the issues it seems is one of its ability to offer a better path for the electrons, water can facilitate that easier than dry powder. This, of course is hearsay and I have no proof nor the documentation to prove it.

[stix]

Ok fine, fair enough. So you do concur that slightly whetted black powder can burn faster given the right conditions? My experience has shown this to be true.

 

As far as susceptibility to static, then I don't know either - it's just something I read. Perhaps some brave person could do tests?.

 

Perhaps it could be Ubes, since he seems to enjoy that sort of thing.

Edited January 5, 2018 by stix

[stix]

Highly milled, fluffed and slightly whetted black powder can be very dangerous.

 

Just be careful.

[Ubehage]

I have also read several places that a little bit of water will make the BP burn more efficiently. Wether that is simply faster burning or if it has more "power", I'm not quite sure

 

I use half a percent of water to make the BP less dusty, yet still free-flowing. In my experience, it doesn't change the burnrate very much.

[stix]

I think Dags posted a good explanation above.

 

It's an interesting phenomenon and I suppose from my limited experience, although I have tested small batches and it is true to me, I have not made a large amounts of black powder, and therefore my default position could be considered hysterical, but careful is more appropriate.

 

[EDIT] It would be too hard to test anyway. By the time you got your apparatus sorted, the water may have already evaporated?

Edited January 6, 2018 by stix

[stix]

Anyway, after exploring that issue, what do you think? Are you able to compress the comp more (ie. in less increments) due to the 0.5% H20? Seems like that is what you are saying.

 

I guess that is an alternative to ricing or granulating to a void dust - I personally like that idea because it would also aid in compaction. But, I haven't made many BP motors. So I probably maybe should never have commented but I do hope it was of some use.

[dagabu]

I have also read several places that a little bit of water will make the BP burn more efficiently. Wether that is simply faster burning or if it has more "power", I'm not quite sure

 

I use half a percent of water to make the BP less dusty, yet still free-flowing. In my experience, it doesn't change the burnrate very much.

 

YES! It allows for a more complete burn, just like I mentioned above, if you add dampness to a truly homogeneous mixture, stoichiometric mixture, it will not speed it up. Not "more power" greater efficiency.

[Mortartube]

Blackpowder core burners. Various fuel mixes. Common practice in the UK (many years ago ) in commercial sky rocket motors was to take commercial meal powder and add varying percentages of charcoal to it to slow it down. The bigger the motor, the more charcoal you would add.

 

The charcoal might be a mixture of airfloat and a coarser mesh. This would have been established through experimentation and then you stuck with the same suppliers and mesh sizes to get consistent results.

 

As far back as 1695 Babington suggests using 2oz charcoal to 1lb meal powder for 1 to 4oz rockets. (Source Brock - Pyrotechnics 1922) This method was used certainly up to the 1930's and probably beyond in UK rocket manufacture.

 

I would suggest that if commercial meal powder were used today, you might need a little more charcoal as it will be almost certainly far more efficiently milled than meal powder of 1695.

[calebkessinger]

I can hand ram a 1lb core burner in under 5 min.. how much faster does a guy need to go?

 

I think increment size directly relates to failures unless you have perfect equipment and fuels.

 

Just some thoughts.

Thinking outside the box leads to good things sometimes.

[ExplosiveCoek]

I actually always use 1x ID increments, also for whistle fuel. 76-23-1 + 1 cuoxycl (perc, kbenzo, vaseline). It's the standard ration everyone uses. Use it up to 22 mm ID rockets. These rockets lift 5-6''

Works for 75-15-10 meal powder rockets too

 

Only get CATO's if I store them too long in too much varying humidity that results in small cracks in the grain.

[Ubehage]

Only get CATO's if I store them too long in too much varying humidity that results in small cracks in the grain.

Interesting. I'll set a few rockets aside and see how they behave in july.

[Mortartube]

Put your rockets somewhere that the cardboard cases can absorb atmospheric moisture then on a good day put them in direct Sun for a few hours. They will almost certainly explode when lit as the cardboard swells and contracts which loosens or cracks the fuel.

Edited January 7, 2018 by Mortartube

[ExplosiveCoek]

@Ubehage, just for kicks, also store one or two in an air tight zip loc bag as a reference will ya? Did this, and haven't had any issues since, no matter how long I store them.

 

@Mortartube, I never use cardboard to be honest. It's too difficult over here to acquire decent tubes, so I'm using PVC. Also this way I'm 100% sure that my tooling will fit, no matter where I buy it. Therefore I've to be 100% sure there are no cato's when I launch these rockets. Also because the headers are too big to ignite in my backyard .

 

Still, if I leave them out in the open air (can get very humid here), they have a high chance too cato. That's why I think that the core/propellant itself also absorbs humidity, if not protected carefully. It is not only the problem of the cardboard tubes.

[Seymour]

I've got 19mm ID tools and tubing that fit nicely in low humidity but in high humidity the rammers literally don't fit inside the swollen tube, if this gives some idea of normal tube reactions to pretty normal humidity variation. Waxing tubes etc has multiple good reasons. That said even with those tubes and no tube treatment I've had IBP motors work after up to 4 years in storage (not airtight storage either).

However that's mostly the IBP End burners. These are reliable... I've NEVER had one cato after years of storage, with 19mm tubes and 4mm diameter Nozzle constriction diameter. Whistle and IBP Nozzleless I've had some work after years with no special storage or tube treatment, but I don't expect them to, at least 1/4 if not over half of those CATO after a year or four.

I'll load increments that once compressed are as tall as the tubes ID as a maximum.

Minimum is usually about half... sure you can do 0.5mm increments, but no point wasting time.

I usually aim for 3/4 the tubes ID for rockets 1" dia and smaller. For a 3" Inside Diameter rocket I tend to like to go with small increments, maybe 1" max.

For things like some End Burners and even more so, fountains, you can get away with a fair bit more than one ID hight increments a lot of the time especially if pressed/rammed at a low pressure, but "get away with a lot of the time" means reliability is just not there. I don't recommend pushing it in this way.

Moral of the story is if you want to store motors, dry out the fuel ingredients and tubes, make your fuel and waterproof it with oil/wax. Waterproof your tubes and clay with the same. Then store them carefully.

As for adding water to BP type fuels, yes it increases burn speed (in not overdone) to a small (but measurable) extent. However the real improvement is cutting down on the dust. Wetting and drying is an easy and great step, but waxing does make a more user friendly fuel.

Edited January 27, 2018 by Seymour

[dagabu]

@Ubehage, just for kicks, also store one or two in an air tight zip loc bag as a reference will ya? Did this, and haven't had any issues since, no matter how long I store them.

 

@Mortartube, I never use cardboard to be honest. It's too difficult over here to acquire decent tubes, so I'm using PVC. Also this way I'm 100% sure that my tooling will fit, no matter where I buy it. Therefore I've to be 100% sure there are no cato's when I launch these rockets. Also because the headers are too big to ignite in my backyard .

 

Still, if I leave them out in the open air (can get very humid here), they have a high chance too cato. That's why I think that the core/propellant itself also absorbs humidity, if not protected carefully. It is not only the problem of the cardboard tubes.

 

I can't use PVC at all to make rockets anymore but I did way back. The issue is the interpretation of law regarding pipe bombs. It makes absolutely no difference around here if it is a rocket and you use less than 62g of comp and even have a rocket body with a parachute (legal description of US acceptable rocket motors that do not need a magazine, local laws vary).

 

If it is contained within a container capable of creating penetrating shrapnel, our locals will arrest you and the DA will charge you with creation and possession of an infernal machine: a machine or apparatus maliciously designed to explode and destroy life or property.

 

Will you beat the rap? Probably but you will spend tens of thousands on a good layer first.

 

Luckily I learned this the easy way at a "Coffee with a Cop" event where the public are given free coffee and can ask questions of the cops and on this Tuesday morning, the DA was in attendance as well. I actually didn't ask the question, the DA asked me what happened to me and I answered that I was making black powder and it caught fire. He made the mistake of asking me if I had served time for it?

 

I replied that I was pursuing my second amendment rights in preparing a signaling canon for the 4th of July celebration. I told him I never even spoke to a cop about it, no charges were filed against me and no case was opened in my name.

 

We got to talking and I told him about the rocket motors I make at PGI and the conversation of course came to legalities. That is when he told me that his office would charge me with creation and possession of an infernal machine if I used anything but paper to make motors and kept them at home. Luckily, all of my motors live in a magazine an hour away, I have no pyro at home.