Spray-n-Pray Fuels

Not everybody who builds cannons wants the latest and greatest contraption with one-touch fuel metering utilizing inline regulators and three-way valves, or even want to dish out ~$3 for a simple syringe fueling setup.

This page is for the people who simply built a basic combustion cannon and want to know what they should hose into the back of the cannon to get it firing.

Of course, I would always recommend using a suitable, clean-burning fuel like propane, butane, or MAP/Pro gas. With an extremely small investment one can fuel most cannons with a syringe (it does become a chore with larger chambers, since large syringes typically only go up to 60 - 100 mL), and not suffer the decrease in power associated with aerosol fuels like deodorant, hair-spray, etc.

If you absolutely must, though, these are my recommendations.

Denatured Ethanol

Of course, if you only have pure ethanol, that will work the same. Ethanol in concentrations above 90% is typically only easily found denatured an in a large metal can like paint thinner/acetone/etc.

Clean burning, doesn't leave any residue, and the main liquid ingredient in most popular aerosol fuels.

The easiest way to use ethanol is to fill a spray bottle with a fine (misting) nozzle (most spray bottles that you can buy in the "hair care" section of pharmacies work) with ethanol, and use a little trial and error to determine the number of "pumps" it takes to fuel your launcher.


This is on the list in its unmetered form.

If you have a decent collection of tools, you probably have a propane torch. This can be used for fueling with a few considerations...

Just realize that the gas coming out of your torch is not just propane, it is a mixture of propane and air already at an optimum air/fuel ratio. Therefore, your goal should be to displace all of the air in your chamber with this mixture.

This usually takes the form of simply hosing gas into the chamber through a cracked cleanout cap. It usually takes several seconds to replace all of the gas already present in the chamber, and overdoing it should provide no problems as at this point you're merely wasting gas instead of creating a richer mixture in the chamber.

Static Guard

This is made almost entirely of alcohol, propane, and isobutane, and a popular fuel because of it.

Starting Fluid

A picky fuel that is nonetheless very powerful. Use on launchers with larger chambers, as smaller chambers will require the most minute amounts to fire.

Most starting fluid contains heptane, which burns very violently, and is in-fact the reference for the "0" on the octane rating scale, causing knocking and detonation in internal combustion engines.

The propellant in starting fluid cans is carbon dioxide, which displaces air on fueling, making this fuel rather finicky.


The last spot on this list is reserved for some of the worst fuels, which for some reason are wildly popular (at least in the United States, international spudders seem to use alcohol more commonly).

These will certainly burn, but the main flammable ingredient is the propellant, which is usually a mixture of propane and isobutane. The rest of the mixture contains a nasty cocktail of chemicals that when heated during combustion can form unexpected by-products and otherwise coat your chamber in a layer of gunk.

These should be used as a last resort. The traditional American fuel is Aqua-Net hair spray, followed closely by Right Guard spray deodorant. Following that are relatively expensive cans of Axe body spray, and other more random aerosol fuels.


I have recently taken to using my DBC with a $1 spray bottle filled with denatured alcohol. Exactly one pump of the spray bottle works phenomenally, and the fuel is cheap and the bottle can also be used for cleaning glass when not used for fueling.

This is merely a curiosity, though. Any other cannon I would use a gaseous fuel like propane in a syringe, and you should too. :p