In a previous instructables I showed how to make a Micro Pen cannon that uses black powder as the propellant. Now many of you out there will be likely to over pack or improperly pack your cannons and wind up blowing it up and hurting yourselves; so for all of you micro cannonniers out there, here's an instructable on how to make prepacked charges for mine, and many other mini cannons out there. As always have fun and be safe.
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Step 1: Supplies
1. Black powder. this can be either made, store bought or salvaged, mine personally is salvaged from model rockets
2. Gum wrappers, preferably 5 brand, they MUST be foil backed for best performance.
3.Straws (2). can be done with only 1 but i just prefer to use two. bendy straws work best in my opinion but non-bendy also work, I'll explain why later.
4. Knife or scissors, basically anything that can be used to cut through the wrappers cleanly. you can rip them with your hands if you really need to but i prefer a clean cut, it wastes less.
5.mortar and pestle, optional but recommended. since you are working on a smaller scale, you need a finer ground powder than you normally would. I'll go into more detail in a later step.
6. ruler(not pictured) optional
THE STRAWS I USED ARE SMALLER THAN YOUR AVERAGE STRAWS YOU MIGHT GET A Mc. Donald's IF YOUR STRAWS HAVE A DIAMETER THAT IS LARGER THAN THAT OF THE BARREL OF YOUR CANNON THE PACKETS WILL BE TOO WIDE TO FIT PROPERLY INTO YOUR CANNON, DOUBLE CHECK THIS BEFORE YOU SPEND YOUR TIME MAKING PACKETS YOU CANT USE.
Step 2: Powder Particle Size
Pieces that are too large will not fit and you cannot have large solid pieces if you are looking for the most efficient burn. i recommend partially grinding the powder to get to a particle size similar to the one labeled below.
Step 3: Creating the Cartridge
1.Open up a wrapper and lay it out flat, foil side down. Place one of the straws ontop of the wrapper, leaving about 1/4 of an inch of wrapper overhanging the straw.
2.Roll the wrapper evenly around the straw, use the whole wrapper, just keep rolling until there's no excess.
3.Now take the excess that you left and tightly (WITHOUT RIPPING THE WRAPPER) fold it over in a way that it can't come undone.
4.Measure out about 3/4 of an inch on the wrapper and mark it either by scoring it or by marking it with a marker.
5.Gently slide the wrapper down the straw until the mark you made is slightly past the end of the straw.
6.Cut the wrapper on your score mark.
7.Slide the rest of the wrapper slightly further down the straw, leaving just enough room to fold the end over again like you did the first time.
Step 4: Filling the Cartridge
take your bendy straw and cut the long end down so that there is about equal lengths of straw on either side of the bendy portion.
bend the straw at a right angle
slip the cartridge onto one end of the straw.
using the other end of the straw as a scoop, fill the space before the bend with black powder. it should be slightly less than would completely fill the cartridge.
when the desired amount is visible in the straw before the bend, straighten the straw and tap the powder down into the cartridge.
another reason for small particle size is that if the powder is too coarse it will clog your straw at the bend.
slide the cartridge off the end slowly, tapping the whole time to ensure the powder settles.
FOR NON-BENDY STRAWS.
they can still be used in exactly the same way, you just have to physically make the bend in the straw and hold it there. the advantage of the bendy straw is that it holds its bend on its own.
Step 5: Finished Products
once you remove the filled cartridge, carefully but securely fold the open end closed being careful not to spill out any powder.
if the cartridge is too full to securely close, then dump a small amount out.
And there you go, you know have ready to go powder packets. Just poke a fuse hole after youve inserted them in the barrel and your set, no more loose powder worries.