First, I know, it's actually a slug-canon. But slug-a-pult just sounds much cooler.

The Slug, every garden owners worst nightmare. (I know, snails are a bit of a pest as well, but I would like to focus on the slug today).
There are many ways to fight the slugs in your garden.
You can put a little salt on them (they will melt).
You can use slugpellets, but there is usualy poison in them. Not very nice for the animals that eat the poisoned slugs.
You can make a slug-kabab (or slug-on-a-stick), but I don't think many would like to see that on a grill.
You can pick them up and throw them in the neighbours garden (but your neighbour will probably throw them back the next day).
And so on....

There are many ways to get rid of a slug but non as satisfying as the use of the Slug-a-pult.
You can shoot the slug a fair distance, and prevent the neighbour from throwing your old slugs back in your garden.
It is also much more fun to shoot the slug, the only icky bit is that you will have to pick up the slug and either train it to crawl into the barrel or you will have to force it in  (the first option could be a little time consuming).
And to top it all off. I just like to think I give the slug a small chance to survive, and give it the ride of its life in the process. I'll bet that the slug will never have traveled this fast, this must be like warp speed in slug-land.

p.s. I noticed that some comments I made in the pictures don't seem to stay where I placed them but end up all over the place, so if that's a bit messy, don't blame me, I didn't shake my monitor that hard....

And before I forget, english is not my native language so there could be some mistakes here and there...

Step 1: Parts and Tools

The parts you will need to built this project will depend on what you can find around the house. And there are not a lot of parts in this project so you might have everything allready.

You can use just about any container you can find for a combustion chamber. But please be a wise Slug-shooter and never use something like a glass jar. There is always the slight possibility that the combustion chamber explodes in your hand, it is not a wise thing to end up with a face full of glass!!

The parts I used to build my Slug-a-pult:
1 plastic container with lid (I think the volume is about 250ml or 15 cubic inch)
1 piece of 3/4" PVC pipe, length is about 30Cm (1 foot)
1 PVC sleeve (I hope I picked the right translation for this one) that will fit tightly on the PVC pipe
1 lighter with a piezo ignition
1 piece of solid core copper wire (I think I used somewhere around 0,7mm² or Gauge 19 but you can use any gauge you can fit)
1 piece of duct tape and some hot glue (there are better ways to glue the pieces together but hotglue is the fastest to cure)
1 can of fuel. Hairspray will probably work just fine but I like to use "Starter spray" (used for starting old/stubborn combustion engines), it usualy contains Diethyl Ether. This will anesthetize the slug and put it in a mild sleep just before launch. This way, when the slug wakes up after the landing it will be very confused and can't find it's way back to your garden.

The Tools I used:
A small saw
A cordless drill
A hobby knife
A hammer
A hot glue gun
A small small screwdriver
Some small pliers

But as it is with the parts, use what you can, need or have.

Step 2: Let the Build Begin!

Let's begin with the lid and sleeve, this is a crucial part. (actualy, all parts are crucial but this sounds a lot cooler).

I used a 10mm (0.4 inch) drill bit and drilled a hole in the middle of the lid to get things going, from there I used a hobby knife to cut the hole to size. Eventualy the PVC sleeve should fit snugly in the hole.
Be very carefull here, cutting in you finger with a very sharp hobbyknife actualy doesn't hurt all that much. But the stitching to close up the wound will hurt very, very much!!!

After inserting the sleeve, you can hotglue the two together. The lid I used hapened to have a nice reservoir for the glue to settle in, if yours doesn't, try to get a good amount of glue on both parts. The glue is for holding the two together and make an airtight seal.

Step 3: Preparing the Lighter

Before you do any work on the lighter, you should empty it completely so there is no flameble gas left inside. You are not going to need or use it anyway.
The fastest way to do this is to use a small screwdriver (or something similar) and push on the valve on the bottom of the lighter. This is where you would normaly re-fill the lighter with gas, be carefull that there are no sparks or flames nearby because there is more gas in a small lighter then you would think. The gas is compressed to a liquid in there, and will expand when it is released.
Also mind your fingers, because of the gas expanding it will get very cold when it comes out.
If there is no valve on the bottom of your lighter, then you will have to empty it the oldfashion way. Push the button and blow out the flame, but keep a hold of that button (it is best to do this outside), this could take a while so you might wanna pack some lunch, or at least an apple or something. You could try to turn up de gas to speed things up a bit but be carefull if you let go of the button and have to push it again, your flame could be crazy high!!
If you want to check if the lighter is empty, push the button (there should be no flame) and listen if you hear the gas escaping. If you are still not shure you can smell the lighter.

Now for the fun part of this bit.
Take apart the lighter and do so very carefully, we will need to put back some of the parts.
Take of the metal windshield and the button, below the button there should be a spring and the piezo igniter, you can take them out too.
Under the peizo, there can be a small rubber disk. The pieces that are taken off now will have to go back on when you are finished modifying the lighter so put them aside.

You should see a small metal tube on top of the lighter, where the gas came out. This is connected to the valve system. This  valve can usualy be screwed out of the lighter. After you take this out, you can be 100% shure that all the pressurized gas is out of the lighter. Although it is not necassary to take it out for this to work, it is highly recommended for safety purposes.

Take the decorative foil of the lighter, or you will be gluing the foil to the container later on. This will be a very weak point if you don't.

Step 4: Finishing Up the Lighter

If you have big hands like me.... You are not going to like this bit, sorry.

First you have to drill two small holes in the side of the lighter, the diameter and location of the holes is different for every lighter I think. These holes are where the wires go through that are going to make the spark that makes the boom that is going to give our slug it's first flying lesson. In English this means, read this part first and you can probably figure out where you would want to drill.

Now, take your piece of copper wire and strip off some of the insulation, 1Cm (1/2 Inch) should be enough. Now take your hamer and beat the cra...... sorry. Put the copper wire on a solid surface and flatten it out a bit, copper is a very soft metal so it should be easy going.
Don't worry about how big it gets, you can clip it to size with a smal wirecutter. You want as much contact as possible but you don't want to make it as thin as tin foil, find a middleway and be done with it!

Now comes the bit we big-handed-people are not going to like.

First, put in the rubber disk.
(If there was no rubber disk in your lighter when you opened it up, then you can skip this bit about the rubber disk, because in your lighter there probably was no rubber disk needed. But if you realy want to know, then you are very welcome to read the rubber disk bit. Not that it is very long. Actualy, now that I think of it. As far as I know, that was all there is about the rubber disk. So you can skip this bit about skipping the bit about the rubber disk...... what? oh, sorry. Let's continue).

Now you will have to manhandle the tiny wire in place. The flat copper end must end up on top of the rubber disk and tight against the side. The piezo ignition will have to go back in there with it soon, so you have very little space left.

Now take the piezo and bend its wire to the side, you will have to eyeball where to drill the hole for it. You want the hole on the same side as the copper wire, but as far apart as posible to prevent "leaking" a spark in there and misfire a lot.

Next, it is time to put the piezo ignition back in it's place and at the same time wiggle it's wire through the hole you made for it. It took me some time, 3 lighters, and if I remember correctly, some words were spoken pretty loudly wich I can not repeat here.
So take a deep breath, sit in a comfortable position, think about your happy-place, get very zen and you might break my record in this exercise.

After you have brutaly abused some perfectly good lighters and finaly got it right at lightrer # .. ( <- fill in your number of broken lighters), you can cut the wires to the same length. Make them at least 1Cm (1/2 Inch) and cut them in an angle so they face eachother (sort of).
Now you can put back the spring, button and the metal bit, if needed. And test the lighter, see if it sparks at the tip of the wires. You can put them closer or further apart to get a better spark, play around with it a bit. Don't touch the wires when you are clicking though, it could bite.

Step 5: Final Step of the Build

Now that your lighter modification is completed and gives nice and steady sparks, it is time to connect the lighter to the combustion chamber.

You need to drill two holes in the bottom of the container, this is where the wires you just made on the lighter go through in a little while. So you will have to eyeball (again) where these should be. Keep in mind that you need to be able to push the button when we're done.

Try to fit the lighter first without any glue, just to see if you guessed the location of the holes right. If not, you might be able to seal up the holes with a piece of duct tape on the inside of the container and try again. Don't get too picky, you can still bend the wires a bit when you're done.

If you are happy with the location of the holes, then you are ready for the hot glue gun.
Get a generous blob of glue in between the wires and around them, this is going to make the holes airtight again. Don't get too enthusiastic and empty out a complete gluegun on this puppy, because it could glue the lighter out of order. And more important, hot glue is...  eeehhh...  well.. Hot! So mind your fingers.
After you get some glue around the wires, put a little blob on the lower end of the lighter as well and carefully place the lighter on the container. Now press firmly to get the glue all the way around the holes and seal everything up real good.

Now would be a good time to let it rest a bit and let the glue harden.
(place personal pause music here and maybe get a drink or some nuts)
When the glue is hardend (or you run out of nuts) get the gluegun back in action and be generous with glue. Make the connection as strong as you can.
(again, harden time, drink, nuts, you know what I mean)

Normaly, this would be it, but I have tested this design in the field. At the fifth testshot the lighter got blown completely of the back of the combustion chamber, hotglue wasn't enough for this monster. So, Duct Tape To The Rescue!!!
Put as much duct tape on this as you like, just don't blame me if you run out ok?

Step 6: Test Firing

First, see if the barrel (the piece of 3/4 inch PVC pipe) will fit tight in the sleeve. This should fit so tight, you don't need anything more to keep it in its place while firing. If yours feels too loose, use some duct tape to secure the barrel to the sleeve. If you don't, you end up shooting your barrel away with every slug you launch and that could end up being a very expensive hobby.

Next, you will need to lubricate the inside of the barrel with petroleum jelly. There are many way's to do this, I'll give you a few ideas to start with.
You can use a small paintbrush and "paint" the inside of the barrel with petroleum jelly.
You can put in a big blob of jelly and hold that end of the barrel up, now heat the location of the jelly and it should drip down and lubricate in the process. Don't use too much heat, I allmost melted my barrel the first try.
The lazy man's way is to let a slug to do the work for you. First you put in a blob of jelly and load the slug behind it, during the first launch, the slug will push the blob through the barrel for you (at no extra cost).

Now you are ready to load your first slug.
But you will have to find the slug first.
On a sunny day, you won't find many around. Slugs like it cool and moist so look around at sunset or early in the morning, slugs will most probably be just about everywhere. If you must have one right now, and right now is around midday, then your best bet will be to look under leaves, flower pots, stones, anywhere where it is cool and moist.

You could train your slug to enter by itself but that could take a while. Slugs are slow by nature, and when they get evicted, well, let's just say they won't be running. The other option is to wrestle your slug in there, slugs are surprisingly malleable. But at least try to find a slug that looks like it could fit. You might have to persuade the slug a little but that's where the petroleum jelly comes in and helpes out a bit. I know that slugs are slimy and icky and stuff but sometimes there is no other way but to get your hands dirty. Rinsing your fingers and the slug in some water sometimes helps a bit but have a rag nearby to clean your hands.

Now, from this moment on, you are on the clock. If you look at your barrel for a while you will see that the slug is trying to make a run for it. So, jam your barrel into the sleeve (and use some duct tape if needed). Unscrew the complete barrel/sleeve assembly, spray some fuel into the combustion chamber and screw the barrel back on. You will need very little fuel for this to work, and leave a little oxigen in there as well or it won't fire. This will take some trial and error to get it right, don't worry, my first slug was at 3/4 of the barrel before I got my first shot.

In the video, you see test fire #3.
I've edited about 1 min 40sec back to 20sec. Taken out all the boring mis fires, still trying to get the fuel/oxygen mix right (and make the weirdo in the frame look a little less like an idiot).

And don't forget to be very carefull with the Slug-a-pult. As most of you probably have noticed, this is a miniature potato canon, slugs may be malleable, but your friends eye is not!!! Just use some common sense and never point this where you don't want to shoot it. 
Think a little about what you are doing and you should be fine.

Thank you for sticking with me for this ride, hopefully see you the next time.
I also hope you've enjoyed reading my first Instructable and will build your very own mean, green, slug-shooting-machine. And maybe even improve on it.
Any thoughts, questions, remarks and or comments are very welcome.

This would be great at shooting snails as well. Great job!
Thank you, but wouldn't the snail's house be in the way? The slug has to make an airtight seal to be effective.<br>I tried to shoot a very smal slug one time and it shot about 2 meters. But i have to admit, the sound it made, had me laughing for the next half hour. That was the wettest fart i ever heard :o)
Yes, now that I give it some more thought, the shell probably wouldn't make a proper seal. Maybe some reusable plastic shells (to put the snail in) that come apart once out of the barrel?
Well, there is a solution for every problem...<br>We have a pear-tree in our garden and i think we will end up with well over 100Kilo's of pears (again). We like pears, but not that much. So we will have a healthy suply of perfectly shootable pears. I guess everybody has some fruit or vegy plant with some left-over's.<br>Use this as a plug behind the snail as a perfect seal. This way the snail even has an in flight meal.
the worlds first supersonic slug lol
Because slugs are very slow creatures, I expect to get the first sonic boom in a week or 2 ;o)
Nice idea!!! I was wondering if it would work with lighter gas... Did you tried it?
Thanks for your comment.<br>I haven't tried lightergas so far (I have 2 can's of startergas and my car just keeps starting on it's own so I have to empty them this way ;o)<br>But i think it should work. I guess that every flamable gas could be used, though not every gas has the same power. Some gasses burn faster than others so it might even be a better solution then the can's i have to empty.