Explosive Black Powder

March 28, 2013 Facebook Twitter LinkedIn Google+ Uncategorized

Black powder 

Originally : mixture of Potassium nitrate + charcoal + sulfur 

Standard  : 74 % Potassium nitrate + 15,6 %  Charcoal + 10,4 % Sulfur 

Military   : 72 % Sodium Nitrate + 16 % Charcoal + 12 % Sulfur  (all + 2%)

Some Fuzes : 70% Potassium nitrate + 14 % Semibituminous coal + 16 % Sulfur    

Grains : Glazed with graphite

Burning rate : Depend of the charcoal used

                        Increased is reached by confining the powde

                        Decrease is caused by    – increasing the nitrate percentage

                                                                 and decreasing the charcoal percentage

                                                              – more than 0.2 % of moisture

                                                              – mixing instead of milling the ingredients

                                                              – using sodium nitrate instead of potassium  


 Grain sizes : From coarser than 4 mesh to finer than 200 mesh

                       Sodium nitrates is divided in three classes

                       A – saluting charges

                       B – Practice bombs

                       C – Torpedo impulse charges

Sensitivity :  ignition by flame, incandescent particles, electric spark, friction,  

                      impact. Ignites spontaneously at 300 degrees centigrade.

Stability   :   Corrodes steel, brass & copper

Usage : Rocket & missiles propulsion

                          Primer, delay, bursting charges, spotting charges, expelling charges, fuzes

             Safety fuze ( common burn rate = 1 foot in 40 sec)

 Substitution : Benite – (KNO3 + Charcoal + Sulfur), Primer, base igniter bags                         Eimite – Artillery primers                        Boron Potassium – delay elements (granular or pellets)                        MOX 2B – Spotting charge, explosive filler
Manufacture : Charcoal and Sulfur are pulverized in a hollow drum called ball mill ( by means of steel balls).
                          The saltpeter is crushed separately.                          The mixture of charcoal, sulfur, saltpeter and water  is grounded and mixed with

                          heavy rolls for  several hours.

                          The mixture is pressed, the solid block obtained is cracked and reduced to the desire size.   

                          For several hours the grains are tumbled in a wooden drum, 

                          Graphite is added to form a film over the grains ( the glazing).

                          Grain sizes are designated from F to 7F (finest) for fine grain and  C, 2C …  for larger grain,

                          A letter is the fineness, g letter if the grain is glazed.

                          Smokeless powder is a product of nitroglycerin and guncotton.