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Parts by weight


Zpyro

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Im new to making stars of Any kind and was wondering IF you People could hela me with this newbie question.

 

How much of each chemical does this mean?

 

Red Metallic Fueled Star: Name: Buell Red

Source: Dave Buell

Chemical

Potassium Perchlorate 8.75

Strontium Carbonate 6.25

Magnalium, granular, 200 mesh 3.5

Parlon 3.25

Red Gum 1.75

Dextrin 1.25

Notes:

Moisten with 50/50 Alcohol/Water mix.

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It means grams, ounces, pounds, kilo... You decide ;)

Use the same unit for all chemicals, and weigh the chemicals individually.

That's what it means by 'parts by weight'.

I hope this is helpful.

Edited by Ubehage
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I like to break formulas into percentages, and multiply my desired final weight by the percentage to decide how much of each chemical to use. So for this particular composition you have:

 

Potassium Perchlorate 8.75

Strontium Carbonate 6.25

Magnalium, granular, 200 mesh 3.5

Parlon 3.25

Red Gum 1.75

Dextrin 1.25

Total parts 24.75

 

Let's use the perc for example

8.75/24.75=35.35%

 

If I wanted to make a 1 pound batch then I'd multiply 454 grams by 35.35%, which equals 160.49 grams. Do the same for each chemical, and you can make any size batch you wish.

Edited by BurritoBandito
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Many thanks for a fast reply. Even if i suspected as much, it's nice to have it confirmed!

 

I figured i could see each chemical as grams, i tried that. But My results was disepointing. My cylinder stars started to crack when they dried.

I just made an order for a precison pocket scale. So maybe this Will make the compound more stabel.

 

Another question!

 

Im not able to roll stars, i press them one by one. Can i still use cylinder shape stars in sphere's?

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If they cracked there can be some different issues, one is not enough binder, it's easy to fix just raise the binder content by 1% and see if that helps.

An other problem can be that the binder didn't activate, to fix that raise the ammount of solvent your binder needs (for dextrine watter (e.g. 3/7 alcohol water ) for red gum alcohol).

An other issue can be the use of to coarse materials.

Also when pumping one of the main effects is the pressure that got applied and the drying speed.

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