Introduction: Reusable, Water Resistant Blowgun/Airgun Darts

About: AKA Roborovski, and Cowscankill for several years. I'm a mechanical engineering undergrad.
I need air powered darts that I can mass produce and hopefully reuse for my blowgun and various .50 cal air guns. This is the design I came up with that uses cheap, easy to find household materials.
The water resistance is good for when you keep reusing darts, since breath is rather moist. 
I would technically call these semi-reusable because some pneumatic guns I own will actually destroy the cone upon impact with a target or bend the nail so much that they aren't safe to use again.
This Instructable was made for .50 cal or 1/2" nail darts.
If you aren't using the same bore size as me, you can modify the design slightly or use the same cone dimensions and trim them to fit in your barrel.
These work great in pneumatic guns like https://www.instructables.com/id/Cascade-Failure-Triggered-Double-Burst-Disk-Pneuma/
As a quick demo of how fast and easy they are to make, here is a little video:

Step 1: Materials

There are three parts to every dart: the cone, the tip, and the bond between the two.

For the cone, duct tape works really well. You can customize the darts to be different colors and even glow in the dark. I use three different colors to distinguish my shots from two friends of mine who wanted to shoot some targets. The yellow darts made in this Instuctable were specially made for a colorblind friend who can't see the red or green darts when they fall in grass or on the ground.

For the tip, I use nails. Boxes of nails are easy to buy and one box will last you forever. I have a ton of different sizes in my shed so I have many options available. Preferably, use a nail with a large, flat head for fitting in the cone. Screws can also be used, but from experience are a pain to pull out of targets and reuse. I've used two different types of nails, but they are both 2.5" long. That is my favorite length to use, but any size is viable.

For the bond, I use hot glue. Cheap, sets up fast, and can make several darts per minute. You could use epoxy or something, but since some of my darts will be destroyed in one shot, I'd rather not waste expensive glue.

To make the darts, I use a ruler, marker, scissors, razor, and cutting board.

Don't forget to have a piece of blowgun/barrel material to test each dart. They tend to be slightly different every time I make them.

Step 2: Getting Started

Once you measure this once, you'll never need to measure again!

I found for the 1/2" PVC bore that I use, 2 1/4" is the  perfect size needed to just barely fit the cones. Start off by measuring on you're cutting board every 2 1/4" and marking it with the marker. (I gave myself a margin of 1" first). Make as many marks as you can fit.
Do this again on the opposite side and make sure the marks are parallel. (I drew dotted lines on the outer boundaries as quick reference markers)

Once you're done marking, start laying down the duct tape horizontally, in the same direction as the markings.
Use the ruler to cut from one side of markings to the other, making perpendicular cuts. The excess pieces can be peeled and thrown out.
I can fit 5 on this cutting board, and I have 4 columns marked. This gives me 20 cones per session.

Step 3: Making a Cone

To make the cone close on itself without needing more tape/glue, I cut out little tabs that will fold over the whole thing. These tabs are 45 degree triangles. They don't have to be measured! As long as the 45 degree cut is above the midpoint on the side of the tape, it will work. If you want to maximize the size of the tab, however, you can measure or make a template like I did. The triangle is 23mm x 23mm on each side, or you can measure 1" from the bottom and cut starting there.
I eyeballed my first set of cones and they all came out slightly different, but worked exactly the same.
Using whatever method you choose, do this to the whole column.

After all of that, take one piece of tape and prepare for folding it. I would recommend just following the pictures below. Alternatively, visit the video in the introduction--it goes over everything!

Once you use all of the tape, heat up the glue gun and prepare for gluing.

Step 4: Finishing Up

To finish these and keep the cones from falling off, I use a bit of hot glue. Slide the cone down the nail about an inch, then surround the base of the head with a bit of glue. Too much will make the cone messy, too little won't hold that well. Just enough is when the excess glue squeezes out and holds the nail from on top.

The darts can now be sharpened on a bench grinder, with a file, or whatever you like to use. They can even be used as is, and should stick into softer targets like archery mats. 

Alternatively, the tips can be sharpened ahead of time and the cones can also be made in advance, and you can mix and match different color cones with different style tips.

Step 5: Conclusion

I pack my darts into a little cardboard box for carrying out to the shooting area. The box that the nails come in works great for holding the darts.
The green darts are for a friend and are put into a custom cardstock box. 
The yellow darts will also be given in a custom box for the colorblind friend.
The last picture shows the prototype darts that led to the design in this Instructable.

In action videos to come!

That's all for now, thanks for reading!