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BengalFlair

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It is the firework which made me pyro-addict forever from the age of about 12 or 14. I have just translated the local term ‘uron tubri’. Those thrilling sweet memories and the composition of my first made firework are still in my mind although I have not done it during about last 25 years.

It consists of a tiny clay terracotta pot having two holes. Small one is for exhaust which can be tuned with scrapper and the large for charging composition which is finally sealed with clay. The actual thrilling part of this firework is that, one has to fly it with his own hand, gripping it between two fingers and leave it with a twist judging the appropriate thrust, keeping the exhaust hole down as it can spin in air and fly away. Traditionally no fuse is used and lighted it with burning charcoal of a smoldering dry coconut leaf stick touching to the exhaust hole. The main drawback of this firework is that the red-hot pots return to ground.

City rises and the vacant lands, pastures, agriculture fields are decreasing rapidly. So these types of fireworks are gradually becoming obsolete because of their “falling back to ground” issue.

The composition is also funny . It is as follows:-

Potassium nitrate - 12

Aluminum- 6 (20-60 mesh turnings from Al utensil factories)

Sulfur- 3

Charcoal (fine powder) 1 (did not know the term ‘air-float’ at that time)

Brunt conch shell powder-1

This composition is also used to make good ground fountains with nice white sparks.

 

I am very curious about the existence of this kind of firework elsewhere in our planet. If you have any idea please do share..

 

I’ve embedded a video I made recently on this. Check it out and comment..

 

http://www.youtube.com/watch?v=0wEhodEDT8I&feature=share&list=UUggj81qQpLnYMMSl0fFUvfQ

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Very interesting and cool effects! Thank you for sharing this neat firework from your part of the world. I love seeing new stuff like this. I am guessing, correct me if I am wrong, that this is a traditional fountain design and throwing the small ones into the air is a secondary way to use them, or is this the intendind use, to fly?
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That was most interesting. I would love to see how they are made. But for use in our country the casing would have to be made of a paper type of case. This could be done I think. Then a means to spin it without touching it with any part of our body (this could be done as will).

The way that it flies is how a stringer works but we use a side hole to start and maintain the spin.

And now a question. What does "Brunt conch shell powder" do in the comp?

I am very please with the new items that you are bring into the forum and showing us.........2smile.gif ...........Pat

Edited by patsroom
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I think it might be burnt conch shell powder. If it was a carbonised shell from a shellfish, it might make a granular charcoal for spark effect.
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hi bengalflair,

 

thanks for sharing the wonderful video . i am from the same part of india where you are from and its a pity that all nice and wonderful fireworks that the whole world enjoys are being banned here. well we pyros have to adjust as and when the situation demands. and for the record whenever aluminium is mixed with kno3 it is advised that a little % of calcium or boric acid is added to negate the chemical reaction for alu and kno3.its a safety precaution as the combination al and kno3 produces nitrates which will corrode the alu and make the device go dud or even in worst case cause an explosion by builtup of hydrogen sulphide gas. burnt conch shell is nothing but pure calcium. it basically cools the reaction down. otherwise the alu will corrode.

regards,

pyroind

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bengalflair has worked hard by pounding the clay well. good job. because whenever i do it i mix a little bentonite clay and small broken pieces of terracota fountain pots which i have already used. its like "grog" with the clay. the clay is also special as i get it from potters who in turn get it from river ganges, for making idols and process it. and in Bengal whenever fountains are considered they are always made of terracotta. there are competitions held as whose fountain spray reaches the highest without a cracked pot. also the pots for senior pyros are made by specialized potters who for years are making these pots. the local name for this is "tubri". i used to get mine from a renowned potter named "AK.P." the pots bengalflair has used is made by very potters and its very rare that you will find these commonly anywhere.
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i saw the tubri, last year i think, the pot suprised me a bit, shame you didnt win, also suprising was the coconut four inch shell, and the three pound parachute flare rocket, a very skilled pyro checkout his channel guys awesome shells, im going there now.

 

 

Dan.

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i saw the tubri, last year i think, the pot suprised me a bit, shame you didnt win, also suprising was the coconut four inch shell, and the three pound parachute flare rocket, a very skilled pyro checkout his channel guys awesome shells, im going there now.

 

 

Dan.

 

Haha, I have also seen the coconut shell, though it was long time ago. Didn't realize it was the same guy. Brilliant! biggrin2.gif

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neat little things! Looks like the really old stuff you see in old lithographs and books that describe fireworks around 1600. Thanks for sharing with us!
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I think it might be burnt conch shell powder. If it was a carbonised shell from a shellfish, it might make a granular charcoal for spark effect.

hi bengalflair,

 

thanks for sharing the wonderful video . i am from the same part of india where you are from and its a pity that all nice and wonderful fireworks that the whole world enjoys are being banned here. well we pyros have to adjust as and when the situation demands. and for the record whenever aluminium is mixed with kno3 it is advised that a little % of calcium or boric acid is added to negate the chemical reaction for alu and kno3.its a safety precaution as the combination al and kno3 produces nitrates which will corrode the alu and make the device go dud or even in worst case cause an explosion by builtup of hydrogen sulphide gas. burnt conch shell is nothing but pure calcium. it basically cools the reaction down. otherwise the alu will corrode.

regards,

pyroind

 

Thanks to all you guys who liked and commented and especially to Dan who has told about me to the forum. Some questions have risen about burnt conch shell powder and I think I should say something in this matter.

 

Conch shells are mainly made of calcium carbonate (CaCO3). By heating about 10000C it decomposes to calcium oxide (CaO) releasing carbon dioxide (CO2).Calcium oxide is also called quick lime which is not a stable compound. By storing in open it reacts with the moisture from the air and forms calcium hydroxide [Ca(OH)2 ] generating heat. Calcium oxide and hydroxide in some condition also reacts with carbon dioxide and converts back to calcium carbonate. So brunt conch shell powder contains mostly of calcium hydroxide (salked lime) and some calcium carbonate, (not pure calcium).I have replaced it with calcium hydroxide in this composition with success.

 

To suppress Al and nitrate reactions it is said to make the mixture slightly acidic with a little boric acid (not calcium) but due to basic in nature, burnt conch shell powder is not only useless in suppressing Al and nitrate reaction but makes it more prone to reaction.. No nitrate but respective metal amides and ammonia are formed during the reaction.

 

It is a traditional formula and the pyros then planed to fly it with their hands, so I think burnt conch shell powder was used as burn rate inhibitor for smooth burning of the composition. That time the pyros did not give importance to stability of the mixture as they used dry mixture with large granular Al and burnt off all the composition about within a day.

Edited by BengalFlair
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im sure im not the only one that appreciates your work, you know your stuff and can teach a thing or two, credit where credit is due.

 

Come on start a thread on the ground spinners, there is no info that i can find here or anywhere, i for one want the comp, the more to make with nitrate the better.

 

Dan.

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  • 5 months later...
i found that to be awesome and im very interested in learning if meybe it could be used like a stinger..as mentioned above...very cool..thanx
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these aluminium turnings looks like coffemill milled aluminium foil. Edited by Oinikis
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aluminum foil or not its cool as hell..lol.. seriously i wanna try this..its just sitting there begging ya not too..
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  • 7 months later...

Thats excellent !!!

Glad to see these 'URON TUBRI's in this forum.....
I heard a trick to explode these terracotta pots high in the air....
After packing the composition in the pot, a small steel ball (from a bi-cycle wheel bearing), is usually put in the pot...

This is to be done before sealing the pot off with clay.

Still I doubt about the safety, as the small falling fragments as well as the steel ball may be dangerous.

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Thanks for the nice video and information.Me too a pyrotechnician from Bengal,India, though my skills have been rusted by a few years.

BTW regarding the 'self destruct' mechanism of "uron Tubri' I came across two methods in a Bengali book on pyrotechnics written by Samarendranath Pandey( AKA Swapankumar).

One of them was the ball bearing technique as mentioned by shovik. The second one was a bit bizarre. It says about putting a tiny piece of calcium carbide wrapped in a cellophane paper at the top of the charge before sealing it with clay. The ball bearing methods worked for quite a many, tried the carbide method once, but it was absorbing moisture continuously and getting warm, so abandoned the idea.

Nevertheless that book(and my first book on pyrotechnics for that matter) contained many sugar/chlorate/colorant formulation for Uran Tubri's. Typical colorants were Ba/Sr carbonate and nitrates,CuSO4 and NaOxalate and a few with Barium Chlor. Besides, there were many KN-Charcoal-Sulph composition listed.

One uncommon one was KN:Sugar:Charcoal =4:2:1, and it worked.

I've a uron tubri formulation with Na-Bicarbonate and which might corroborate the purpose of having lime (or "shamuk pora chun" as its locally called) as acid reducer. However I have copied that formula hastily from somebody and it might be a little erroneous.

Edited by sora
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