Composantes de la poudre

The primary difference between 'a' and 'g' grades is processing. Both
powders begin as milled 'meal' powder. The potassium nitrate, charcoal and
sulfur are milled into an extremely fine powder. This milling process takes
many hours and is usually done by remotely operated equipment due to the
inherent danger of the process. The meal powder is consolidated under high
pressure into a 'mill cake' or 'press cake' of solid Black Powder by
hydraulic press. The cake is dried, and crushed into grains. Both types are
then screened to remove fines, and to grade the grain sizes.

Subsequent polishing of the powders may be done in a tumbler. Blasting "a"
type powders are not usually tumbled. If they are tumbled, it is just for a
short time to knock off any sharp an d long projections. Sporting "g" type
powders are tumbled with a tiny amount of graphite to polish the grains.
The base formula is the same. The graphite is not part of the basic Black
Powder formula.

The graphite does act as a burn rate modifier, slowing the burn rate
slightly. But primarily, the graphite serves as a surface lubricant to
make the powder flow more easily when loading guns. It also serves the
cosmetic purpose of making the powder shiny and pretty. The grain sizes
are different for sporting and blasting Black Powder.



et voila ... jai fini pour se sois :P

Pour ceux qui seraient intéressés, le guano utilisé dans les poudres triple base, proviens des excréments d’oiseaux. Sur certaines Iles les oiseaux y nichent depuis des centenaires et font ce qui est naturel, Ces fientes s’accumulent et se solidifient pour être finalement minés et utilisés comme source de Nitrates( NO3). Lors de ma carrière j’ai travaillé pour une firme ou nous utilisions ce guano dans la composition d'une colle qui servait à faire des produits laminés comme l’arborite. C’est de la mer** mais ça vaut son pesant d’or, si nous savons ou l’utiliser.

Avec un petit sourire aux lèvres

Effectivement, cela me rappelle une aventure de Tintin...