Black Powder Storage

[paulvallandigham]

I am always amused when someone is reluctant to store Black powder in its cans in their garage, when they usually don't think twice about storing cleaning solvents, paint, propane, and gasoline for the lawmower in the garage. The fumes from the gasoline are the most dangerous, the most explosive, and the most easy to ignite! The old oil based paints are pretty good accelerants, and the solvents- denatured alcohol, naptha, mineral spirits, acetone, etc. are all good burners. All should be stored in cool, dry places, just like your black powder.

 

[Zonie]

bramble: Yup, ye hit tha nail on tha head!

zonie

 

[Mad Monk]

Incorrect on the burn rate thing.

Blasters' Handbook
E.I. duPont de Nemours and Company
15th Ed.
Wilmington, DE

Velocity.

Black powders do not have true velocities, whereas detonating explosives do.

Their rate of burning is affected by confinement. In the open, trains of black powder burn very slowly, measurable in seconds per foot. Confined, as in steel pipes, speeds of explosions have been timed at values from 560 feet per second for very coarse granulations to 2,070 feet per second for the finer granulations.

 

[Mad Monk]

Forgot.

Storage temperatures.

Sub-freezing temperatures do not harm black powder.

You do not want to expose black powder to temperatures above 170 degrees F.

When the temperature goes above 170 F a tiny bit of the sulfur will turn to a vapor without going through the liquid state. While the actual melting point of sulfur is higher than 170 F a tiny bit will turn to a vapor. In the vapor state the sulfur will become chemically active. It then sort of attacks the potassium nitrate. End products being potassium sulfate a free lower oxides of nitrogen which become acidic with moisture, with makes the reaction somewhat self-accelerating.

This does not make it blow up in the storage container. The powder just gets weaker and corrosive.
The mineral content of the charcoal used is caustic in nature. Acts to buffer the chemical changes to a certain extent. Once the caustics from the charcoal are consumed the powder can go over the hill rather quickly. At least as far as usefullness in the gun.