5 replies to this topic

[bigtonyicu]

Hi everyone,



I was wondering if anyone knew the solubility of potassium nitrate in different solvent (other then water) for example methanol, ethanol, isopropyl alcohol.. basically anything that has a high evaporation rate.



I recently made a batch of color changing starts that turned out great… but the burn time was Way!!! too long, I'd like to be able to make a few test start with a different solvent to test them, not really looking for something that could be ramped up to production quantity, just something that would speed up the process from over a week to a few days… and suggestion would be greatly appreciated.



(and yes I'm asking for KNO3 solvents not KClO4 because perchlorates are impossible to get in Canada with out jumping through loops till you're blue in the face, so I'm been doing my colors with KClO3 or KNO3… and lets not open the debate on KClLO3 here.. I KNOW. I've given up on blues L )

[YT2095]

KNO3 is a Polar molecule, and as such will require a polar solvent, now with a Dielectric constant of around 20, there`s are Few organic solvents that are A] Polar and B] with a dielectric constant that high or higher.

there are some though

Dimethyl sulphoxide (DMSO), Formic acid and Methanol will work also but won`t dissolve much.
IPA won`t really work at all, in fact it`s used for salting out!

hope that helps a little.

edited to add; if you Do use DMSO, be VERY carefull, anything it dissolves will pass the skin to blood barrier within seconds, only a little slower than actually Injecting yourself with the stuff!
the extends to the Pyro nasties like Copper or Barium salts etc...

Edited by YT2095, 24 May 2008 - 08:10 AM.

[dr thrust]

hi, unfortunately theres no quick route to star drying, kno3 being a salt only dissolves readily in water or we would all be doing it! try smaller stars, an efficient drying cabinet( but let your stars dry naturally for a couple days before adding to the cabinet) the use of a resorcinol resin resin as a binder and fuel to speed up drying times as been discussed on the forum, you could change your method, with pumped and even pressing under force ( 1ton) needing at lot less damping, if its for quick testing i recently used a yellow star formula that called for 50%, water 50% alcohol these dried quite fast these had dextrin and red gum as binders so you could up the solvent by including red gum, how where you testing your stars? they do burn much faster though the air

Edited by chris m, 24 May 2008 - 12:24 PM.

[Arthur Brown]

Stars only function well in their intended environment! You should be able to tell when stars are dry as they will reach constant weight. Try a few, as rolled then after days in a dry place. the weight could go down significantly in the first few days. They are not ready to fire til they have been at constant weight for a day or so. Expect anything up to 10% weight loss for dry looking comps more if they look moist when formed. Do NOT over damp compounds as some - notably glitter - don't work if over damped.

Multi layer stars may need to be part dried before putting the next layer on to permit the subsequent layers to adhere without incorporating.

[bigtonyicu]

how where you testing your stars? they do burn much faster though the air

I used a Star Gun

Multi layer stars may need to be part dried before putting the next layer on to permit the subsequent layers to adhere without incorporating.

I let them dry for about 36-48 hours between layers... Might try letting them dry longer.

[seymour]

I'm been doing my colors with KClO3 or KNO3… and lets not open the debate on KClLO3 here.. I KNOW. I've given up on blues L )

You can make perfectly good blues with chlorate...