Napalm is the name given to a mixture of various fuels or combustible materials, with little to no use in civilian applications, but previously used in warfare. Apart from being used in demonstrations of slow-burning materials, napalm doesn't have much use in amateur science, and most of the time tends to cross into kewl territory.
There are two main types of napalm:
- Oil-based with aluminum soap thickener: this is the classic version of napalm. Is consists of co-precipitated aluminium salts of naphthenic and palmitic acids. The term napalm comes from the name of the latter two compounds. Sometimes called Napalm-A.
- Oil-based with polymeric thickener: Also known as Napalm-B or supernapalm, it consists of petroleum fuel mixed with a polymeric thickening agent. This is the most common and known form. It consists of 46% polystyrene, 33% gasoline and 21% benzene. The classic homemade napalm is derived from this composition.
Napalm appears as a flammable liquid or thick jelly, depending on the composition. It is extremely flammable, and has a strong petroleum odor. It is insoluble in water and most polar solvents, but tends to form a fine suspension with most hydrocarbon liquids.
During combustion, napalm gives off large amounts of combustion gasses, as well as carbon monoxide and lots and lots of soot as well lots of heat.
Napalm is classified in most countries as an incendiary weapon and therefore it's not available in civilian applications, where professional flamethrowers are much better and safer at controlled burnings.
Really, if napalm is what you want to make, you might need to broaden your notion about experimental chemistry. But if you really want to know:
Original napalm can be made by adding palmitic and stearic acids to soluble magnesium or aluminium ions (magnesium or aluminium chlorides e.g.), which precipitates the fatty acid salts of said metals. An organic solvent like naphta is used to obtain the jelly form. A similar preparation can be found here and here.
To make Napalm B, in a metal container, such as an empty tin can, pour gasoline or some other petroleum-derived fuel and add small or broken pieces of polystyrene. The polystyrene will dissolve in the gasoline and its volume will shrink, as it's mostly 95% air. Keep adding styrofoam blocks until you reach the desired viscosity. Napalm-B also contains benzene, so you can also add it as well, though this will cause the mixture to get thin. Other agents can also be added.
Observe and time how long it takes for a sample of napalm of a specific composition to burn completely. No really, that's pretty much the only useful thing you can do with napalm. Oh, and inhaling its toxic combustion gasses. There really isn't much else you can do with it. Its harmful black smoke makes it unsuitable for use in closed spaces and compared to other fuel materials, napalm has terrible performance: it doesn't generate sufficient heat for its volume, gives off way too much soot, stinks everything, etc. All these make napalm a terrible fuel for general heating.
- If you follow a "double polystyrene" recipe of napalm, you will end up with a putty or jelly-like substance. This is useful for starting campfires when bushwhacking. However you will need to hold it in closed bottles when carrying it, due to its strong smell.
Napalm is extremely flammable, though less flammable than gasoline. When it catches fire, it is extremely difficult to extinguish. If it lands on your skin, it will stick there and cause horrible burns. The combustion of napalm generates large amounts of carbon monoxide which is extremely toxic. Napalm-B contains benzene which is a known carcinogen.
If you really want to store napalm, do it in metal containers, away from any sources of ignition, preferably in a bucket with sand, in the event of a fire. Since the the common form gives off petroleum odor, the bottle should be sealed.
Burning napalm or its wastes releases large amounts of toxic fumes and should only be done in incinerators with afterburners, or in a remote location.