This is my first instructable so please bare with me. I have also decided to make it a relatively short one.

In this instructable I am going to show you how to make your own smoke fluid for any smoke machine. This does not include fog machines which use dry ice. Perhaps obvious to most, but just wanted to point that out.

Step 1: What You Will Need

- Glycerol, Glycerin or Glycerine (same thing)
- Distilled water
- Measuring jug
- Container to store solution

Step 2: Where to Get Your Ingredients From

Gylcerol, Glycerine and glycerin are the same thing. It is easily and cheaply obtainable from your local chemist. Either behind the counter or on the shelf, you will find it next to the throat medicines as this is one of its uses -- eases discomfort from harsh coughing. It will also make you more than regular if you drink too much of it!

Distilled water should be easy to come by. Places like Halfords (England), or outlets which sell car consumables should sell this. At a push you can get away with dionised water. The aim here is to get a water that is about as free from lime and other impurities as possible.

I'm hoping I don't need to talk about the measuring jug and container.

Step 3: Method

For high density smoke...
Make a solution of 30% glycerol. The remaining 70% is made up with the distilled water.

For medium density smoke...
Make a solution of 20% glycerol. The remaining 80% is made up with the distilled water.

For low density smoke...
Make a solution of 15% glycerol. The remaining 85% is made up with the distilled water.

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For purposes of clarity, should I want to make a solution of high density smoke fluid I would simply pour all of the glycerol into my container. I would then fill the empty glycerol bottle with water and pour that into my container. I would then do this a second time to achieve (roughly) a 30/70 mix of glycerol to water. You don't have to be exact with this.
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Once you have poured the required amount of each liquid into your container, shake for a few minutes to ensure that the two have completely mixed. You now have your own smoke fluid at a fraction of the cost of commercial smoke fluid.

Step 4: Preservation

You may find that you want to keep your smoke fluid for a period of time. If your container is clean, and your smoke machine doesn't already have traces of mould in it then you should be ok for about a month. Less if you have made up a solution that is less than 30% glycerol.

Anything past a month and you may want to add a preservative (antibacterial agent) to extend its life. Given that this solution will eventually be aspirated and breathed in, it is important that you don't add too much of something, or the wrong thing for that matter!

I would recommend simply adding 2-3 drops of bleach to every litre. This will keep any chance of infection down and will still be safe to people in the concentrations given out when it's used.

Step 5: Make It Smell!

You can also add a few drops of essences to your fluid to make it smell. Typically your smoke will smell / taste ever so very slightly sweet. The emphasis here is again; just a few drops.