Projectiles - Dart cannon

I thought I'd make a cannon, and use the little dart I made when I built my blow dart gun with a laser sight as the projectile.

Making projectile launching things that shoot projectiles can be fun.

And stupid.

This project was both.

I started with a jumbo bag of party poppers.

They might be called something different where you live, but they are a little explosive device designed to deliver a quantity of litter into the environment.

They do it surprisingly effectively.

I pulled all the streamers and other junk out to reveal the small firework.

Then it was a simple matter of finding a tube that would fit over the bit that goes bang.

I found a bic pen worked a treat, and the tapered end meant it was easy to create the required seal by just forcing it into the handle of the popper, to surround the firework.

Like this.












Before jamming the pen into place I put the dart in at the firework end.

And this is where the stupid bit comes to the fore...

Then I pulled the string.

Luckily I had taken the precaution of wearing a scratched pair of sunglasses, and aiming in the general direction of the back wall of my shed (garage/iron clad building full of junk in my backyard).

The result was that I no longer own my little hand made blow gun dart.

It's gone now.

It's definitely still in the shed, but it really could be anywhere.

It went away really, really fast, and obviously didn't want to be found.

I think it must hate me.

The pen/cannon has a new fracture as well. You can see it in the milky burnt picture in the pic before last.

I put the inky bit of the pen loosely into the little cannon and re-loaded it to see how much power it had, and was a little surprised to see it actually shift it ... perhaps....6 feet.

That could come in handy if you ever needed to project a full stop to the far wall of whatever room you were in.

Very handy.



According to my calculations, all this means I could shoot a 44 magnum slug nearly a thousandth of an inch.

Which is nice.

Generally I prefer to blog about things that are kid friendly, but this time I guess I have to say...

Don't try this at home...

Unless you really, really want to.

But please, please, put on an old pair of sunglasses or some safety goggles, or wrap your kids in a mattress or something. And maybe just launch a polystyrene ball from a bean bag or a pug of potato or something. It's always embarrassing to rock up to emergency with a little dart poking into your kid's brain through one of the soft, squidgy, eye portals that the gods built into heads as a sick party joke to make you look silly when you rock up to emergency with a little dart poking into your brain.

Don't encourage them.

Besides, wearing safety goggles shows you and your kids that you at least have a certain confidence in your ability to create mayhem.

I count the cannonic loss of my little home made blow gun dart a total success.


120 Things in 20 years thinks it might be a good time to quit while I'm ahead. I can see making cannons is a thing I could rapidly get addicted to. Like crack and cross-stitch, some things are (apparently) too addictive to mess with.

Just say no.


 

Projectiles - Building a blow gun with laser sight

I thought I'd build a blow dart gun with a laser sight.

It turned out to be a total success.

It works well, and is much more fun than regular darts of the non-blown variety.

I started with a couple of pins, some string, some cotton, and a thin pipe. A broken car aerial works well, so does a pen casing. Even a drinking straw works at a pinch. The longer the better, and it's best to avoid flexible things as your pipe. Drinking straws tend to be a little less accurate.

I started by piercing the string so I had four strings stuck to my pin.

 I taped up the strings so they wouldn't move when I started to wrap them.

This next bit is really important.

Add a loop of cotton running the length of the pin.

Take some cotton and wrap it tightly to make a binding along about a third of the length of the pin.

I also made one where I used electrical heat shrink instead of cotton binding. It worked well, and was much faster to make, but didn't look as nice as one with binding.

Trying to tie off  the end of a binding is difficult unless you have that loop we added.

To finish your binding, pass the loose end through the loop.

Then pull the back of the loop all the way back. This will draw in the lose end, and secure it by tucking it under itself... under the binding.

That's really important string tech. As long as you plan it beforehand and add that loop it's easy, but without the loop, it's next to impossible.

 The end result looks something like this.

Next I took another pin and frayed the string.

Wool would work better, but I didn't have any.

When it's fully frayed, it looks like this.

You can us it like this, but it was a little slow, and not very accurate.










I trimmed mine down a bit.











The point of the tail is to create drag so it flies straight, and with the sharp end up the front where it belongs.

If you have even one thin strand longer than the others it can cause trouble.

A long strand will make your dart turn off course a bit, and can also get stuck between your lip and the tube, resulting in a blowing noise but no shooting.

An easy way to trim it is to put it into the blow pipe and cut any excess with scissors.

Next, I found my container full of prototyping plastic. I explain it in this post about it's possible use in making hand made fishing lures, but basically it's stuff that gets soft at 65 degrees centigrade or so, and sets hard once it cools.

Next, I got hold of a laser pointer ($15 or so), then it was a simple matter of heating up some prototyping plastic, and wrapping it around both the tube, and my laser pointer.

I added three screws that sit through the plastic so I can tighten them against the laser to adjust where it points in relation to the tube. That way, it's easy to adjust and make certain everything lines up properly.



I shot some video while I was sighting it. I placed the laser sighted blow dart gun in a clamp, and repeatedly shot it, and adjusted the screws to get it more accurate. A simple matter of firing, then moving the dot to the same spot as the dart hit.