(If the images are broken, I apologise, as I'm new to this)
So this will be the product:
-Foam; stock, blue or fbr
-E-tape, or something alike
-wire; i use copper wire, but it's up to you
Start by cutting a dart at a desired length. Here's a streamline dart (that has its tip breaking off) next to a set-square. I'll be cutting it at around 2 inches (about 5 cm)
You'll need the excess foam that you've cut off to fill in the hole of the dart, so don't throw it away.
Take your excess foam, and cut out a small piece that you can fold and push into the hole of the dart.
Have it flush with the top.
Now you need a weight. Take your wire and cut it to size. The length of the wire is entirely optional, and you should cut it to suit your blasters. Obviously, the longer the wire, the heavier the weight. I cut my wire the same length of the hypotenuse of the set-square shown above.
Now take your wire, and pierce the dart through to the other side. This will make the next step easier, and prevent the foam in the middle from flying out.
Begin to wind the wire down the dart TIGHTLY. The last thing you want is for the wire to expose itself when leaving the barrel of your blaster.
Once complete, you can snip the wire protuding out the side off.
Then wrap the wire with E-tape TIGHTLY. The tape shouldn't touch the walls of your barrel when you use the dart, otherwise it'll only create friction.
It works flawlessly in my 16mm conduit. The darts fly straight, and get ranges comparible to hotglue tips. They are easily consistent in preformance compared to hotglue tips, and don't NEARLY sting as much as hotglue tips. Personally, I believe these are a nice alternative to slugs, and I'm sure using a different kind of foam wouldn't be to hard.