Makeshift gram scale (balancita improvisada)

Hace tiempo tengo ganas de volver a incursionar aunque sea ligeramente en la pirotecnia. Hace unos días pude comprar 1 Kg de NO3K (nitrato de potasio), y me decidí a lanzarme a la tarea. Cuando llegó el momento de mezclar los componentes de la pólvora me encontré con la ligera dificultad de que todos los que han publicado fórmulas insisten en que las proporciones son por peso, no por volumen. De modo que busqué una balanza de cocina que tengo entre mis cosas, pero su rango es hasta 3 Kg, con una división mínima de 20 g, lo cual es demasiado grueso para mi necesidad de proceder a mezclar pequeñas cantidades.

O sea que tuve que interrumpir la tarea de moler y tamizar el NO3K para ponerme a improvisar una balanza con la sensibilidad que necesito.

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Long time I have wanted to return to venture even slightly in pyrotechnics. A few days ago I bought 1 kg of NO3K (potassium nitrate), and I decided to throw myself into the task. When it came time to mix the components of gunpowder I found the slight difficulty that all those who have published formulas insist that the proportions are by weight, not volume. So I looked for a kitchen scale I have in my stuff, but its range is up to 3 kg, with a minimum of 20 g division, which is too thick for my need for mixing small quantities.

So I had to interrupt the task of milling and sieving NO3K to get to improvise a balance with the sensitivity I need.

Step 1: Specs (especificaciones)

Mi diseño debe cumplir algunos puntos básicos:

1 debe ser factible
2 debe ser fácil
3 debe ser rápido
4 debe ser barato
5 debe tener sensibilidad de alrededor de 2 gramos
6 debe tener poco o nulo rozamiento
7 debe ser fácil de usar

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My design must meet some basic points:

1 should be feasible
2 must be easy
3 must be fast
4 must be cheap
5 should be sensitive to about 2 grams
6 should have little or no friction
7 should be easy to use

Comments

[Lefrançois]

Grinders for coffee grinder would be the case or better yet a device to grind spices

[rimar2000]

Pardon, surely your comment is for another instructable. Anyway, thanks.

[yoyology]

I grasped the concept from the first photo, but kept wondering what you were going to use for the reference weights. Water is the perfect answer.

This would also work for "English" non-metric weight systems, since 1 fluid ounce of distilled water weighs 1 ounce. Of course, grams are smaller and therefore more precise.

Excellent work!

[rimar2000]

Thanks for your kind comment, yoyology.

[Dr Qui]

Clever idea for a reasonably accurate gram scale. I look forward to you fireworks Ibles. N03K is on the controlled list here in Northern Ireland even sulfur is quite hard to obtain now, we have to make the best of what can be made from match heads, paper caps and sparklers and that limits you to small bangers.

[rimar2000]

Thanks Dr.Qui for your comment and your concern.

My rockets are in "stand by" due to lack of a mill to process some grams of NO3K, sugar, Carbon and Sulfur. Mortar and pestle make the task too sluggish.

Since Saturday I am making a balls mill, but I am having troubles with the motor, it works well but heats after 3 or 4 minutes. Today I will replace it, at least that is my plan. The proximity of the holidays makes everything a bit more complicated. Here in Argentina the school/college courses finish in december, and consequently the parents and grandparents we are forced to attend many long, boring ceremonies related to our children and grandchildren.

[Dr Qui]

Ah Christmas, keeping grumpy men from the sanctity of their sheds for over 2000 years! lol.  whats worse is that you are not allowed to comment on the fact that your related children are tone deaf and have no musical ability yet.


Hopefully the post Christmas left overs will yield some items you can use to build a ball mill.

[Bill WW]

Excellent as usual, Osvaldo.
Ten cuidado con la pirotecnia

[rimar2000]

Thanks, Bill. Pirotecnia is very laborious if you have not the components finely grinded, and this is my case. To grind 150 g of NO3K I took almost a day using a porcelain mortar. Sulfur is even worst.

I have only 4 almost finished rockets, I have thought to try them tonight, if it does not rain. The chances of failure are very high.

[Dr Qui]

Some sore of motorized ball mill would help with this, i have played around with this using 12mm ball bearings in a sealed metal can, you can get some very fine powders from this, a small 6-12v motor should be enough to run something and i'm sure the rest could be obtained from scrap.

I dont know where i heard this but, I remember seeing something aout how the carbon and sulfur should be milled together to get the carbon to bond to as much sulfur as possible

[rimar2000]

I answered this comment above, Dr. Qui.

[Bill WW]

I purchased this scale for US$16.50, advertised as accurate to 0.1 gram. I used it in an experiment to calculate magnetic field strength versus distance. Hope to post the results of my experiment as an Instructable soon.
Buying a scale is not as much fun as making one as you did.
When I was ten years old we purchased sulfur at the local pharmacy to make gunpowder. We thought the other ingredient was from old electric batteries. Fortunately we were not successful.

Compre esta escala para EE.UU. 16,50 dolares, anunciado como una precisión de 0,1 gramo. Lo use en un experimento para calcular la intensidad de campo magnetico respecto a la distancia. Espero volver a publicar los resultados de mi experimento como un instructivo pronto.
La compra de una escala no es tan divertido como hacer uno como tú.
Cuando yo tenía diez años hemos comprado azufre en la farmacia local para hacer pólvora. Pensamos que el otro ingrediente fue antiguas baterías eléctricas. Afortunadamente, no tuvimos éxito.

[Dr Qui]

I too bought a set of scales like these, i got mine on eBay directly from Hong Kong for about £4.99 postage inc. they are very useful indeed.

[Bill WW]

Yes, but I feel a bit guilty admitting on this site that I did not make it myself!

[Bill WW]

Yes, but I feel a bit guilty admitting on this site that I did not make it myself!

[Dr Qui]

I know what you mean but you cant make everything,  those mass produced items are needed to make the bespoke stuff.

I have reached the age where I work out if the price of an item is to expensive based on how much hassle it would be to build my own version, how safe mine would be and how wrecked I would be from building it, or more importantly if i could even build the thing in the first place. if its under 10 pounds i don't even think i just buy it.

The other point is why waste the fuel money time and hassle of traipsing round stores only to have some disinterested teenager stare at you blankly and ask "whats that?" or "I'll have to go ask one of the older guys".

I think eBay is great, combined with my smart phone and tablet I can order stuff from anywhere.  I feel like Wylie Coyote ordering things from the ACME company,  only these days you click a button and then pace back and forward waiting for the post man.

[Bill WW]

I get most of my "whats that?" questions from my wife

.Bill

[rimar2000]

Me too, Bill. She ask, I answer, she forget. Tomorrow, same question again.

[rimar2000]

HAHAHA!!!

Like "...some disinterested teenager stare at you blankly and ask "whats that?" or "I'll have to go ask one of the older guys...". I get almost every day that response. Not only teenagers, old men/women say it, too.

[rimar2000]

That scale is beautiful and useful!

To get Carbon for gunpowder, the best option is to make a bonfire with pieces of pinewood, wait some minutes and take off the embers. Leave them aside to go out, or just soaking in a bucket of water. In the last case, you must wait 1 or 2 days to they dry. After, grind the pieces (as you can do it) to get a finely ground powder. All this work is easy but a bit boring. My first 4 rockets were fails, but I learned must do some changes.

[Bill WW]

Fortunate that I did not have all this information sixty years ago!
Suerte de que yo no tenía toda esta información hace sesenta años!

Abrazo y Feliz Navidad y Prospero Ano Nuevo para ti y tu familia.

Bill

[rimar2000]

Gracias Bill, retribuyo tus buenos deseos para las fiestas y el 2013.

[marcellahella]

Smart!

[rimar2000]

Thanks for the praise, Marcella!

[elgatoandaluz]

Me encanta lo que inventas.
Idea genial, simple....Enhorabuena!!!
Observo tus instrutables con curiosidad....

Un abrazo desde la Costa del Sol-Malaga

[rimar2000]

Gracias, elgatoandaluz! Esta noche, si no llueve, probaré los primeros 4 cohetes. Hay altas probabilidades de falla, Ojalá alguno de ellos suba bien.

[rimar2000]

Fracaso total, los 4 primeros cohetes fallaron. Pero eso me dio la pauta de algunos cambios que debo hacer a la construcción, o sea que bienvenidas sean las fallas.

[jpalacios3]

totalmente de acuerdo con tus especificaciones de diseno, trato de tenerls en cuenta cuando construyo algo, no es facil reunir todos esos requisitos pero como dice un refran gringo: KISS (keep it simple Sir)................ un abrazo Osvaldo
PD: cuidado con la pirotecnia por favor

[rimar2000]

Gracias, jpalacios3. Yo a ese principio lo tenía como "Keep it Simple, Stupid". Pero lo cierto es que las cosas demasiado simples suelen no funcionar bien. Por suerte en este caso mis necesidades eran muy elementales, y no tuve problemas.

[ChrysN]

Great design!

[rimar2000]

Thanks, ChrysN. I am satisfied for the result: ugly but useful. Considering it was done in a hurry, is not so bad.

[Phil B]

Very good and very clever.

[rimar2000]

Thanks, Phil. Your praise is the praise of a MASTER.

[ToyMaker]

This is beautiful. Elegant simplicity.
I have some flat stainless steel from windshield wiper blades and will try to reproduce your design. I don't have ready access to a syringe but coins are very consistent in weight from one to the next. New ones should serve as calibration weights.
Thank you for a wonderful idea.

[rimar2000]

Thanks for your kind words, ToyMaker. These flat blades can work very well, I have some of them too. Warn don't exceed the max elastic bending limit, ie the wire don't deforms.

My design is a lot improvable, it raised in middle of a hurry to make some rockets for next Christmas and New Year celebrations.

[rncbme]

I continue to be amazed at your creativeness!

[rimar2000]

"Necessity is the mother of invention", rncbme. The alternatives were "this or nothing". It is working pretty well.

Thanks for your comment.

[tholopotami]

Once again accept my admiration! A physicist like me would be lost in a world of precision limits, elastic modules, non-linearity, mechanical tolerances, stiffness and staff like this before taking the pliers and do what you did!

[rimar2000]

Well, one of my favorite sayings is "perfect is enemy of good". All my projects have flaws, bugs, and are mostly ugly, but almost all function almost well.

Thanks for your comment!