Drying (Rocket Motor)

Before you begin, all of the chemicals must be thoroughly dry. You can place potassium nitrate and sodium nitrate
in non-aluminum pots (i.e. steel, iron. Pyrex. enamel, etc.). and dry them in a kitchen oven for 1 to 2 hours at 250° Fahrenheit. When they are not mixed with anything, both chemicals are very stable, and there is no hazard in doing this. An aluminum pot will work, but these chemicals will etch the surface of the metal, and ruin the finish.
You can dry charcoal in a kitchen oven, but if it gets too hot. it will ignite and burn like it does in a Bar-B-Que. You’ll have to keep the temperature at 225° to 250° Fahrenheit, and you can expect a noticeable odor.
You can dry coal and carbon black at 225° to 250° Fahrenheit, but the odor is so unpleasant that you’ll want to do it outdoors. An electric frying pan with a cover works fine, but you’ll have to place the cover askew, and open its vent to let the steam escape. If you don’t, the water will recondense. and drip back into the pan.
Baking soda and powdered sugar are dried before they are packaged, and no further drying is necessary.
Sulfur, red gum. vinsol resin, and goma laca shellac either melt or give off unpleasant odors at low temperatures, so spread them on a sheet of plastic, and dry them in the sun. Sun-drying isn’t as effective as oven-drying, but these chemicals are used in such small quantities that tiny, residual amounts of moisture shouldn’t be a problem.