I took the old mower blade to the shop and with a grinder took it back to bare metal. I then took Birchwood Casey Bore Scrubber and wiped the metal clean of all fowling. I then took Birchwood Casey Sheath and protected the metal. I then took isopropyl alcohol and wiped the Sheath off the metal. This would be as exact to the manner in which I treat my rifles before and while hunting.
I then marked out 14 separate spots on the blade to be tested. The powders were in order 1-14
1= Goex 2f
2= Goex 3f
3= Swiss 2f
4= Swiss 3f
5= Kik 3f
6= Pyrodex RS
7= Pyrodex P
8= Triple Se7en 2f
9= Triple Se7en 3f
10= American Pioneer Powder 3f
11= Black Mag 3
12= Goex 4f
13= metal untreated
14= metal treated with Kroll Oil
It should be pointed out in order not to contaminate any of the testing areas, each area was covered with a specimen cup (lower corner of the picture) so that the flash from the flame next to an area could not drive over. Also the tested were conducted outside where it is 34 degrees, and very damp... just like I hunt in.
After all the areas were fired, I then took a Q-tip, and moistened it with Kroll Oil and scribed between all test areas ... again, to make sure no contamination for the other powder would effect the rusting properties. In #13 the metal was left bare just to see the effect the damp weather might have played on it. In #14 I wiped that area clean with Kroll Oil so that it would simulate a clean protected barrel in the same environment.
The blade was placed out in my wood working shop which is unheated. It is off the ground in a cool dry space where nothing but the powder's own chemical reactions should effect it. I will check the blade each day to note the condition of the burn marks. Since the powders were ignited at approximately noon, I will use that time frame to recheck.
Any other ideas you would like to try? I have no other kinds of powder around the house.