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MK's Sugar Rockets - The Professional Era

MinamotoKobayashi

By MinamotoKobayashi
in Pyrotechnics

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MinamotoKobayashi Newbie

MinamotoKobayashi

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Hello forum.

Many things happened during last months: I have learned many lessons,

tried and found many solutions (often with the well-knowed system

TRY-ERROR-CHANGE-RETRY), and finally refined the entire project.

I have also invested many moneys to buy all the needed chems and tools to

become a serious pyro-man.

I must thanks Mr. Jason (NeighborJ) a lot for his patience and expertness.

A lot of formulas, modifications and procedures come directly from him.

Without his help probably my actual state will be at a greenhorn level :)

This is not a R-Candy only related thread ... I will explain the whole

procedure to build nice fireworks using sugar rockets.



Chapter one: the tools.

------------------------------


The 10tons hydraulic press:


24269233548_dba3e669ea_b.jpg


The custom multi-purpose drying box:


38089873052_55d6f92137_b.jpg


24269269108_52147a92af_b.jpg


37411998704_9f014e86ca_b.jpg


The box is alimentated by a 5A 11.1V LiPo cell, that is able to provide enough current to the fans for about 7 days:


37411997304_b8ed9b11b5_b.jpg


Different screen meshes:


37411995954_f909ba2d77_b.jpg


The Lortone ballmill with 100x1.5mm brass balls medias:


24269230158_4d2aaabe86_b.jpg


The star plate (it can create 10x10mm 49 cylinder stars):


38121103211_7a4d1e9127_b.jpg


The 4 channel radio-controlled system (to ignite fireworks from a distance up to 300 meters):


38089747622_0f5c5c93e0_b.jpg


The goggles and the mask to protect myself against harmful dusty chems:


38121149971_0a8f365597_b.jpg


The chems storage room:


24373042188_7196f410d0_b.jpg



Chapter two: making a very good granulated BP with a modified CIA method + pucking and corning.

------------------------------------------------------------------------------------------------------------------------------------


First of all 80 grams of airfloat pine charcoal, 53,2 grams of sulphur and 21,2 grams of dextrin

must be ballmilled for some hours:


24269228108_d7abed41fd_b.jpg


The above doses are calculated to fill my ballmill for half barrell,

exactly a little bit over the brass balls, to obtain a rapid and perfect creation of a very fine compound.

The rotation speed of the original rock tumbler was modified following the good infos

quoted in these sites:





Then 400gr. of potassium nitrate is dissolved in 200ml of boiling water:


24269226428_7bf72c4064_b.jpg


Once all the nitrate is dissolved, the heat is turned off and the premilled mix is dumped into the hot nitrate solution and mixed with a spoon:


24269232028_4c2ee09ab8_b.jpg


The mix is runny and hot so a gentle breeze and constant mixing helps to reduce the H2O content:


38121175781_c51e602250_b.jpg


After it is cooled to room temperature the mix is spread out on waxpaper to dry:


38121172361_9e45ec4eb4_b.jpg


It can be left to completely dry or it can be dried just enough to press it into pucks for corning:


24269219968_45e056a66a_b.jpg


Pressing the wetted black powder to make cylinders suitable to be granulated:


24279586058_95a543fb9d_b.jpg


The BP cylinders ejected and ready to be granulated:


24269222938_56fe9899ed_b.jpg


This is a much better procedure than the method described on pyro creations because you will not

loose any of the dissolved nitrates in the waste water and the exact chemical ratios are 75-15-10+4.

This makes powder which will be faster than the screen mix pucking and corning method because the

nitrate is more intimately incorporated into all the ingredients.

The most difficult part of the entire process is drying the very wet mix without letting the KNO3

crystallize on the surface. The best way to avoid that is to dry it at room temperature without heat

and use a fan to increase airflow.


The final +20-8 granulated and fully dried black powders:


38123319461_10d5dd59a8_b.jpg



Chapter three: making gold glitter stars.

----------------------------------------------------


The N1 modified glitter stars are credited to Ned Gorski and after added with Magnalium by NeighborJ.


Before I start I feel that I need to state that there are a few things which will prevent these stars from performing properly.

One of the more common mistakes is adding too much water, the second common mistake is force drying them.

Both mistakes will cause the Al and MgAl to oxidize and start a chain reaction of degradation.

These kinds of reactions are not a danger unless they react fast enough to create its own heat and self ignite.


Start by weighing out 272 grams of loosely granulated screen mixed BP 75-15-10+4% dextrine (also called pulverone):


38093256052_bf0c52aa8a_b.jpg


Adding 48 grams of sodium bicarbonate, 32 grams of sulphur, 16 grams of dextrin and 4 gram of boric acid:


38070581446_da21bd901a_b.jpg


Screen mixed these chemicals thru a kitchen sieve 3 times then added 32 grams of 325mesh atomized aluminum and 8 grams of

-60+100 mesh MgAl:


38076897146_97038d5924_b.jpg


Gently shaked the batch in a closed box to evenly distribute the metals:


38076899786_ebf4e189e2_b.jpg


At this point 90% demineralized water with 10% isoprophylic alcohol can be added.

I used a spray bottle to slowly add water while shaking the box to expose dry comp.

I don't have an exact water content recorded because different charcoal are more thirsty than others but 18-25% is normal.

It will start to clump in the box when enough moisture is achieved:


38076901026_022f8e2d6f_b.jpg

Edited by MinamotoKobayashi
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MinamotoKobayashi Newbie

MinamotoKobayashi

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  • Author
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The wet compound is coated and pressed with a spatula inside the cylinders of the star plate:




Pressing the wetted golden glitters compound at 2 tons pressure to create the stars:




The stars are ready to be dried:




Now the stars needed to be primed.

Also if they are quite easy to ignite, the stars will benefit from a quick and complete ignition of the entire star surface.

Prime is a good insurance of this and it helps to ensure the display is "crisp" meaning they lite simultaniously and burnout at the same moment.

The cylinders needs to be re-wetted superficially with a spray bottle containing 90% demineralized water and 10% isoprophylic alcohol,

and then floured into a mixture of pulverone plus 10% of silicium.

Here is the primed stars, aka the final product:




Now they are ready to load into shells.

They will not burn properly on the ground because atmospheric oxygen is needed to feed the reaction in the air.

They will burn anyway, but they will turn into a molten blob of slag.

If at any time they get hot while drying it is better set the batch outside in case of accidental ignition.

The risk goes down as they dry, and after 8hrs they are usually dry enough to prevent any reaction at all.



Chapter four: creating nice 4" shells.

------------------------------------------------


First of all an hole is made to insert and glue a straw.

This is necessary because the shell needs to be ignited from the inner center to obtain a simmetric effect after the crack.

A fast fuse is also needed.

With the help of a compass two circles were traced on both the hemis:




Placing the stars around the inner walls of the shells:




Fill the spaces between the stars with enough 20 mesh granulated black powder:




Creating a sort of bags with tissue paper filled with 8 mesh granulated black powder, then placed the bags over the stars and pressing well

to keep the stars in place:




Wrapping an hemis with the help of a tissue paper foil:




Carefully place the wrapped hemis over the other hemis:




Removing the extra paper and tap around the upper hemis with a rubber hammer to compact and fit everything inside:




Gluing the two hemis with a wood glue:




The best option for the 4" shell is to use the 20mm tape with two latitude lines which makes 3 tape rings then repeat the process a second time.

This should create the 30 layers required.

The first ring will be 23.5mm from the pole and the second will be 44.5mm:

Mr. NeighborJ has refined a good way to manually paste the shells in a homogeneous manner, as explained in this video:




Equatorial layer:




First layer:




Second layer:




Third layer. Due to the amount of wetted paper used, the shell needs to be dried for 24 hours:




Placing a small neodimium magnet to easy find the hole after applying the new layers:




Tracing again the circles.

To create a better homogeneous pasting, this time the compass was pointed over the equatorial line, just in the joint of the two shells:




Fourth, fifth and sixth layers pasted.

Finding the magnet with the help of a iron item, removing it and placing the fast fuse.

Other 24 hours are needed to completely dry the shell:





Chapter five: creating a sugar rocket.

-------------------------------------------------


The original cardboard tube: 150mm lenght, 45mm outside diameter, 37mm inside diameter, 4mm wall thickness.

Internal partitions: 20mm for the PET nozzle, 80mm for the propellant, 20mm for the plug, 30mm reserved for other purposes:




Plug and nozzle created from a PET bar with a precision lathe.

Plug: 20mm thickness, 3mm hole, 37mm diameter.

Nozzle: 20mm thickness, 10mm hole, 37mm diameter:




Nozzle pressed and glued with a strong bicomponent epossidic glue:




Nozzle deadly hold with a massive band:




Inside the tube:




Nozzle hole filled with pressed bentonite to avoid spilled compound during the compacting procedure:




130 grams of potassium nitrate, 70 grams sucrose, 2 grams iron oxyde and 6 grams of titanium sponge 450-1000µm.

I used a heavy and thick cast iron cooking pan over an electric cast iron plate to avoid dangerous hot spot that could

accidentally ignite the compound:




Dissolved powders adding 2 big spoons of distilled water:




Cooking the compound at medium heat:




The compound is near to be ready. It is important to stir often the compound for safety reasons and to obtain a homogeneous paste:




Compound dried and melted. Max care is now necessary because it is extremely flammable:




Packing the compound with a PET bar. The fit is perfect, so no compound can get off the sides.

To reach optimal results it is necessary to pack the compound not all together, but the equivalent of two tea spoons every time.

Every time I will apply a pressure with the weight of my body (95 KG).

In that way every part will be well compacted over the previous one:




Well packed and cold compound:




Removing band, bind a spiralled layer of 20mm wide gummed paper:




Removing bentonite from the nozzle and making a 10mm diameter, 40mm deep hole in the propellant:




Gluing and pressing the cap, deadly lock it with a massive band:




Removing band, insert the fast fuse of the shell inside the 3mm plug hole, gluing the shell on the top:




Gluing a suitable long stick, locking the stick with the cardboard tube, the nozzle and the plug with two long tapping screws:




Inserting 3mm fast fuse, keep the fuse locked inside the hole with some small pieces of cotton:




Two beasts of about 770 grams each are ready to be launched:




... and now, the awesome radio-controlled launch:




I'm very proud for the results obtained from this complicated project.

Many many thanks to Mr. NeighborJ for introducing me into this fantastic world. Keep following this thread, this is only the beginning ... :D

Edited by MinamotoKobayashi
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NeighborJ Newbie

NeighborJ

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MK, can you elaborate a bit on the nozzle material you use? PET is not something I'm familiar with. It looks as if it machines well and is quite durable.
MinamotoKobayashi Newbie

MinamotoKobayashi

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Hi Jason.

Polyethylene terephthalate, also knowed as PET, is a friendly atoxic termoplatic resin that has a high melting point, near 260°C.

It is usually used to make plastic bottles for water and sodas.

PVC (polyvinyl chloride) is lighter and cheaper, but has a low melting point, about 100 °C.

POM (polyoxymethylene) is another plastic that I used to make nozzles but it is another plastic that has too low melting point.

A valid alternative to the PET is the Nylon Zellamid (polycaprolactam, PA6): same melting point, cheaper, and easy to shape.

The best choice would be PTFE (polytetrafluoroethylene) also knowed as Teflon, because has very high melting point (near 330°C),

but it is heavier and much more expensive.

Unluckly it is an auto-lubricating plastic, which makes it unsuitable for sticking with the cardboard (poor adhesion to the walls).

 

You can find 1 meter PET BARs on eBay.

It's not very easy to shape this plastic manuallly. Surely You need a lathe, using low speed rotation with sharp and fit tools.

 

In my modest opinion the best choice for a rocket nozzle is bentonite (for small rockets) and aluminum (for big rockets).

But in the middle field I prefer to work with PET or Nylon Zellamid :P .

Edited by MinamotoKobayashi
Sparx88 Newbie

Sparx88

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Very nice info/tech, thank you for sharing.

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MrB Newbie

MrB

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In my modest opinion the best choice for a rocket nozzle is bentonite (for small rockets) and aluminum (for big rockets).

 

Probably not a shock to anyone, but bentonite works great for "small scale", but for large stuff, one really should use graphite. It is more expensive then aluminum, but pretty much isn't affected by erosion, and can be reused infinitely.

MinamotoKobayashi Newbie

MinamotoKobayashi

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Hello Mr.B.

Yes I know graphite, but I think it is a waste of money for this kind of project, because I lose the rocket everytime that I launch one of them.

Besides this, small/medium fireworks do not need to reach high altitudes, so my nozzles needs to resists only for few seconds :P

Edited by MinamotoKobayashi
OldMarine Newbie

OldMarine

Posted
Posted

Powdered graphite added to the clay helps with pressing and does make a more enduring nozzle. It makes the rocket release from the spindle much easier as well. Like MK said, I don't reuse my rockets.

NeighborJ Newbie

NeighborJ

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Posted

While talking a little with MK about his sugar rockets it is clear to me that his motor designs are using the nozzle erosion to prevent over pressurization of the motor case. I'm not certain if a erosion resistant nozzle will work properly with his design. A change in the materials used would certainly require re working the motor dimentions.

 

I can easily see where B is going with his bentonite suggestion. I must say that I agree that the polyester nozzle is not the most environmentally friendly material to use so I would suggest that a non optimized candy fuel mix be used in its place. It could be pressed hot or cold which would reduce the machining time required for each motor and it can be mixed in various ratios to tune the erosion factor. This is of coarse a suggestion but in my mind it would be a quicker construction method and kills several birds with one stone.

MrB Newbie

MrB

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Yes I know graphite, but I think it is a waste of money for this kind of project, because I lose the rocket everytime that I launch one of them.

 

Um... Excuse me for asking, but does that mean you are pretty much just making rather expensive lawn-darts?

I'm assuming that you are shooting these in none "civilized" surroundings, so there is no real lawn to speak of, but putting enough effort in to shooting things like this, and not recovering the rocket housing seems like an opportunity wasted. Examining the corpse tells you a lot, so to speak.

I'd use a bentonite nozzle over a PET one any day, just "design" it to do what you want. Kitty litter is easily turned in to powder, you already got all that needs, making, or buying pottery grog, and using larger then average particle size, should help it bite in to the tube real nice, and help limiting erosion, if that turns out to be a problem. And the upside is... You already seem to have the tools to make the rocket tooling from PET. The grog has a nasty habit of eating the tooling alive, being able to make new from a cheap, hard, workable plastic might be next to ideal... Also saves you the step of having to drill out your partial core, and removing the bentonite.

 

As NeighborJ might be hinting at... Make your rocket fuel, but let it cool before adding it to the rocket. Granulate it, and use rocket tooling to ram a "solid" cored core, with no air inclusions. Tune it to perfection, and add a parachute for recovery.

 

Also. It's none of my concern, but... Get a press. At least a hand cranked one. Your 95 kilos on the end of a PET rod, is nothing like the force you get from even a small mechanical advantage, (from a short lever) and consolidation is, key.

 

Last thing on my mind, for right now at least. Your nozzle. You have a small divergence zone, but there is, as far as i can tell, no picture of the "other" side. Do you have a convergence zone that stretches to the outer edges of the plug? You probably "should", but i'm mostly asking out of curiosity.

 

Anyway, good luck, what ever you do.

MinamotoKobayashi Newbie

MinamotoKobayashi

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x Oldmarine: what is the ideal ratio bentonite:graphite for the nozzle?

 

x NeighborJ and MrB: Sometimes I found the used rockets in the middle of the field, and usually the nozzle has a diameter 1-2mm larger, so I cannot re-use it.

The diameter increment is not a problem for me, because I have found the perfect timer: when the rocket begin to lose thrust, the shell explode :P

 

PET is non-toxic polymer plastic, suitable to the contact with the foods. Usually I launch my rockets in a field reserved for cultivations, so the farmer will found, before or after,

the rockets' carcass, so no plastic will left in the environment.

Usually I buy a 1 meter PET (or PA6 Nylon Zellamid) bar, cut in pieces of 2 cm each and make nozzles and caps. It costs me about 1.5 dollar at piece. It is not so expensive for me, also because I launch only 2 rockets every week.

 

I tried to cool down the compound, granulated it and pressed inside the tube: the rocket exploded.

I tried to press the compound while it is again hot with my hydraulic press at 500 KG pressure: the rocket exploded.

I tried to skip the screws step: plug and nozzle were sput out.

I tried to use bentonite instead PET: same as above.

This rocket is born so, and so must rest.

Probabily it is working at the very edge of a CATO and the internal pressure is a little bit high, but since now I launched more than 15 identical rockets with my original formula

with or without shell on the top, and never happened a CATO.

 

The other side of the nozzle has no divergence, it is not needed. And probably the divergence is not needed on either side.

Edited by MinamotoKobayashi
OldMarine Newbie

OldMarine

Posted
Posted
MK, I use 2% graphite in bentonite cat litter and it presses up really nice.
MrB Newbie

MrB

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The diameter increment is not a problem for me, because I have found the perfect timer: when the rocket begin to lose thrust, the shell explode

 

As long as you are happy with that, i guess it's fine. "most" people launch the rocket, watch it end it's burn, and coast until it reaches it's apex, and that's where they blow the shell. Just means you get higher on a smaller motor.

 

 

I tried to cool down the compound, granulated it and pressed inside the tube: the rocket exploded.

I tried to press the compound while it is again hot with my hydraulic press at 500 KG pressure: the rocket exploded.

 

Sounds like you got a better burn, and needed a larger nozzle, or a nozzle with a convergence zone.

 

 

I tried to use bentonite instead PET: same as above.

 

If it blows out the PET nozzle as a chunk, you need a higher pressure when making it in the tube, or, grog. Possibly both. If it gets blown apart by the pressure, grog might help there to. And graphite.

 

 

The other side of the nozzle has no divergence, it is not needed. And probably the divergence is not needed on either side.

 

I'm no rocket expert, but it is my understanding that the convergence zone both increases thrust, and decreases the risk of a burn through on the side of the tube, just above the nozzle.

 

 

Also, you shooting two of these a week, the farmer tends to plow the fields once, or twice a year. The paper tube is, for most of these, no longer recognizable, the steel bits have rusted, and the nozzle is small enough that the plowing action mostly just ignores it.

At least solid chunks of PET is rather inert, so it shouldn't be a great issue.

MinamotoKobayashi Newbie

MinamotoKobayashi

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Thanks Oldmarine!

MrB, thanks for the suggestions!

But I cannot understand what is "grog". Google translate and DeepL do not show any translation, sorry ... :wacko:

Edited by MinamotoKobayashi
OldMarine Newbie

OldMarine

Posted
Posted

Grog is essentially coarse particles of fired and broken pottery or ceramic added to the nozzle mix to help it bite into and lock onto the tube wall. I use just the Bentonite cat litter with the graphite and have yet to blow a nozzle out of the tube since the clay is granulated it bites into the tubes very well.

MinamotoKobayashi Newbie

MinamotoKobayashi

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Oh now I understand.

But I have solved the question creating a sort of threaded profile in the ending parts of the cardboard tube like this:

 

34796490476_b20d65bf34_b.jpg

 

38315501186_4b00628f9e_b.jpg

 

.. but it works well only with small tube diameters (in this case, 25mm)

This is another project of mine and I will do a full review soon.

You can call this: the "light cheap son" of my last project :P

 

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OldMarine Newbie

OldMarine

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Nice! The clay should grab onto that area very well.

  • 2 weeks later...
MinamotoKobayashi Newbie

MinamotoKobayashi

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Updates 26/11/2017.

---------------------------


- I had problems changing potassium nitrate from the anti-caking version to the not anti-caking one.

In fact the anti-caking version, the one that used for my rockets, is added to magnesiun carbonate to avoid caking,

but as a secondary effect it slow down a lot the performance of the mix. So, using the potassium nitrate in pure form,

the internal pressure raise so much that every rocket made with the new compound exploded :(

So the choices was two: slow down the internal combustion adding 5% of sodium bicarbonate or enlarge the rocket nozzle

diameter from 10mm to 12mm.

Both the solutions worked very well, but the second was surely the more professional and faster to realize.


- I commissioned a new star plate with bigger cylinders to optimize and to speed up the granulating process of the BP:

24775898628_3352ec7d52_b.jpg


The BP cylinders:

38616053952_90d6833132_b.jpg



- I added a second layer made by fast BP over the first layer made by slow BP (also called pulverone):

37761089675_3b56aa1a22_b.jpg


This trick add two nice new features:


1. It ensure a better ignition of all the stars (avoiding the so-called "blinded stars");

2. Add an ignition delay of the stars, making the peony wider and more durable.


And finally, here is the result of the new modded rocket/stars:




.. a wider, longer, beautiful peony!

  • Like 2
calebkessinger Newbie

calebkessinger

Posted
Posted

Very nice !

:D

dynomike1 Newbie

dynomike1

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Posted

Hi Minimoto good looking rocket. I wonder if i could get the specs on that press.

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