dynomike1 Posted September 25, 2012 Posted September 25, 2012 I have been looking at a lot of formulas and the problem that i am having now is the factor. Where i am having trouble is converting the factor to oz., or grams.. Like a factor of 37=? oz.
Mumbles Posted September 25, 2012 Posted September 25, 2012 This is a reasonably simple conversion. I'll show you two examples just to get it all covered. A majority of formulas add to 100 parts, which makes them easy to convert into percentages for calculation in any unit you'd like, and is nice for comparing different formulas. If you find commercial formulas, they'll probably be specific to batch size, so may be out of a total of 30 for instance, because each batch is 30lbs. Tigertail:Potassium Nitrate - 44Charcoal - 44Sulfur - 6SGRS - 6 This one is out of 100 parts, so it is both 44 parts potassium nitrate and 44% potassium nitrate. If you wanted to make a batch with a total weight of 40oz or 40g, you just multiply by .44. Since the nitrate is 44% of the formula, it will be 44% of the total weight. In this case, it would be 17.6 ounces or grams or pounds, or whatever units you're working with. Charcoal will be an identical weight. for the sulfur and SGRS, you multiply 40 by .06, which gives 2.4. If you add up 17.6 + 17.6 + 2.4 + 2.4 you'll find you get your grand total of 40. One of my favorite star formulas is from the Best of AFN III called Spider Star #2. This is a commerical formula. Potassium Nitrate - 15Charcoal - 9Sulfur - 2Dextrin - 2 As you can see this does not add to 100. Instead it adds to 28, which is the number of pounds in the batch. The most direct thing to do is make everything either in batches of 28, or a multiple there of. (pounds, ounces, etc.). If you did that you'd use 15oz potassium nitrate for a 28oz batch, or 45oz potassium nitrate for an 84oz batch. If you want to convert to a percentage like we did before, you divide the parts by the total weight. For potassium nitrate it'd be 15/28, or 53.6%, and so on for the other components. If you wanted to make a 1 kilo (1000g) batch, you'd be best off doing it this way. I posted the amounts you'd need for a 1 kilo batch below rounded to the nearest gram, let me know if you still have questions. Potassium nitrate 536gCharcoal - 321gSulfur - 71gDextrin - 71g As you may notice, it only adds to 999g, this is due to rounding errors compounding by going to the nearest gram.
dynomike1 Posted September 25, 2012 Author Posted September 25, 2012 (edited) Ok i will study on it. I think i am missing something. How would i know how much say Potassium nitrate to put in a say 3" shell? Potassium nitrate 0.55 Airfloat charcoal 0.33 Sulfur 0.07 Dextrin 0.05 Edited September 25, 2012 by dynomike1
FlaMtnBkr Posted September 25, 2012 Posted September 25, 2012 (edited) You make a batch of stars and then just use them until gone. You don't try to make a batch of stars for one 3" shell. The amount of stars will depend on a couple things like density of star, star shape, and the method you build the shell. Just pick how big of a batch you want to make and go from there following Mumbles directions. Edit: It sounds like you are talking about just dumping the chemicals into a shell. You have to make stars first with the chemicals. Edited September 25, 2012 by FlaMtnBkr
mikeee Posted September 26, 2012 Posted September 26, 2012 Kind of like baking a cake.You need to read the recipe several times, to make sure you get it right.You might want to watch a few video's to understand how they go together.Skylighter website has a few video's along with Youtube etc. (Some Youtube video's can be crap)You might also want to hook up with a Pyro club in your area if there is one.Making a mistake in the Pyro world can be painful & expensive.Some chemicals and comps can be very volatile. Mikeee
dynomike1 Posted September 26, 2012 Author Posted September 26, 2012 Hot dam i got it if i dont forget it. I new i was missing something. I want to thank yall for your help.This statement statment is what made my brain click to mumbles directions. Just pick how big of a batch you want to make and go from there following Mumbles directions
dynomike1 Posted September 26, 2012 Author Posted September 26, 2012 I agree. Any thing that i think i am going to buy from skylighter i read and watch the video's first This is probably going to be like it was when i was building my Cannon, started out didnt know anything but learned enough to build it and shoot it safely. It will be awile before i make a batch, my partner is on his way to Itlay i will wait till he gets back. Again thanks.
Peret Posted September 26, 2012 Posted September 26, 2012 There are about 28 grams in an ounce. If you take a formula where the parts add up to 100, for example 75 KNO3, 15 charcoal, 10 sulfur, and take each part to be 1 gram, you end up with roughly (a little short of) 4 ounces of compound. This is about enough stars for a 3 inch ball shell, which generally gross out close to 140 grams (5 ounces) including case and pasting. If you take that as a baseline, you can roughly calculate what you need for other sizes by the ratio of cubes. That is, a 4 inch ball will need (4^3/3^3) times as much, 64/27, about 235 grams (8.4 ounces) of stars.
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