Some priming info.. thoughts?

[braddsn]

Hey guys.. wanted to share something that I noticed through extensive testing of many methods of priming and general shell building. I use different priming methods for different circumstances. However, all else being equal, I have noticed more reliable ignition when my burst is dusted with slow flash booster (50 KNO3, 25 dark al, 25 sulfur). I use 3% by weight.. so another words, I take 1kg of burst and dust it with 30g of this formula. I then use either 70/30 or 35/35/30 for additional booster if needed. My thought is that by dusting the entire burst charge with this slow booster, the temperature reached right before break is higher than just bp alone, or even bp + 70/30. The higher temp aids in ignition. This is the only explanation that I can think of. Feel free to share your thoughts. Edited May 20, 2015 by braddsn

[GMetcalf]

Interesting information braddsn! My thought is that the improved ignition may well be related to the fine metallic coating on all the grains of Black Powder ensuring better conduction of heat throughout the shell, not necessarily a higher temperature. The faster heat conductance resulting in more Black Powder burst charge igniting at once and hence the stars being bathed in more hot gas, increasing their ignition.

Just my thoughts!

[JOPETES]

Hey guys.. wanted to share something that I noticed through extensive testing of many methods of priming and general shell building. I use different priming methods for different circumstances. However, all else being equal, I have noticed more reliable ignition when my burst is dusted with slow flash booster (50 KNO3, 25 dark al, 25 sulfur). I use 3% by weight.. so another words, I take 1kg of burst and dust it with 30g of this formula. I then use either 70/30 or 35/35/30 for additional booster if needed. My thought is that by dusting the entire burst charge with this slow booster, the temperature reached right before break is higher than just bp alone, or even bp + 70/30. The higher temp aids in ignition. This is the only explanation that I can think of. Feel free to share your thoughts.

Phew ... it's very difficult to know exactly what happens inside a shell at the time of opening. I'll give my opinion: rice husk covered with very fast black powder produces more than enough heat to ignite all the stars in the interior of the shell, also thinks that if you add an extra burden 35,35,30 ( Opening PDF) or 70/30 flash will produce even more heat, plus a more powerful opening. The question is not produce much heat inside the shell, but opening the powder (rice husk bp) is very fast so that the fire from spreading inside very quickly and on a regular basis all stars and provide fire Turning the power on, and here also intervenes the number of layers of paper to close the shell and also the fuse spit fire right in the center of the shell. I saw two equal shells 4 inch with stars tiger tail + titanium, one with shell very fast rice + bp and the other shell with rice hulls coated with Kp (KClO4 + carbon + sulfur) and a little reinforcement 35, 35.30 ....... and what was the result? ................. all the stars in the shell with very fast bp ok ignition, but the shell had kp many stars did not ignite. Brad have to know that the very fast high-quality black powder is much faster than wildfire Kp (klo4 + sulfur + carbon), however the Kp gunpowder produces more heat.

 

If you add powder composition of kno3, sulfur and aluminum, boric acid to be added, the presence of water with aluminum and KNO3 can heat the composition and produce autoignition, so boric neutralizing acid or slow this reaction is added.

[braddsn]

Jopetes I agree...too much booster and ignition begins to fail. There is a fine balance between good hard breaks, and too much booster.

[braddsn]

Jopetes: After this last week of testing I have realized that it is VERY important to use very little moisture when adding the last layer of prime (bp). Before, I was adding this layer with plenty of moisture and the star was hard and shiny on the outside. This makes for difficult ignition. I am getting vastly better results priming like you described.