Hexamine fuel tablet
Encyclopedia
Solid fuel
Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating, usually released through combustion....
in tablet
Tablet
A tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose...
form. The tablets burn smokelessly, have a high energy density, do not liquify while burning and leave no ashes. Invented in Murrhardt, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, in 1936, the main component is hexamine (hexamethylenetetramine).
A number of alternative names are in use, including heat tablet and Esbit. Esbit (which stands for Erich Schumms Brennstoff in Tablettenform or Erich Schumm's Fuel in Tablets) is a genericized trademark
Genericized trademark
A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...
as it is used to refer to similar products made by other companies.
Uses
The tablets are used for cooking by campers, the military and relief organizations. They are often used with disposable metal stoves that are included with field ration packs. Backpackers concerned with ultra light gear tend to buy or make their own much lighter stove. An Esbit beverage-can stoveBeverage-can stove
A beverage-can stove is a homemade, ultralight portable stove. The simple design is made entirely from aluminium cans and burns alcohol. Countless variations on the basic design exist....
can be made by cutting off the bottom of an aluminum soft drink can, and turning it upside down to support the fuel tablet. A pot can be supported above this with a circle of poultry netting
Chicken wire
Chicken wire, or poultry netting, is a mesh of wire commonly used to fence poultry livestock. It is made of thin, flexible galvanized wire, with hexagonal gaps...
or metal tent pegs. The burning tablets are sensitive to wind, so a simple windscreen should be used, such as a strip of aluminum foil curved in a circle around the pot and stove. If necessary, the fuel tablet can be placed on a rock or on the dirt, with a pot supported above it by rocks, but this is less than ideal.
Another common use is to provide a safe heat source for model steam engines, such as those manufactured by Wilesco
Wilesco
Wilesco is the trade name of German toy company Wilhelm Schröder GmbH & Co. KG, known for manufacturing live steam toys such as steamrollers, traction engines, and stationary steam engines....
and Mamod
Mamod
The Mamod company is a British toy manufacturer specializing in building live steam models. The company was founded in 1937 in Birmingham in the British midlands by Geoffrey Malins. The name is a contraction of Malins Models'. The first models produced were of stationary steam engines, the company...
.
They may be used as a heat source for a pop pop boat
Pop pop boat
A pop-pop boat is a toy with a very simple heat engine without moving parts, powered by a candle or oil burner. The name comes from the noise the boats make. Other names are putt-putt boat, crazy boat, flash-steamer, hot-air-boat, pulsating water engine boat...
.
Advantages and disadvantages
Hexamine is prepared by the reaction of formaldehyde and ammonia. In an acid environment hexamine is converted to formaldehydeFormaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...
, which is toxic.
Fuel tablets are simple, ultra-lightweight compared to other stove options, and compact; the entire stove system and fuel can be stored inside a small 850ml cooking pot. As with trioxane, hexamine has an almost infinite shelf life if stored properly. However, the heat given off cannot be easily adjusted, so water can be boiled, but cooking requiring simmering
Simmering
Simmering is a food preparation technique in which foods are cooked in hot liquids kept at or just below the boiling point of water , but higher than poaching temperature...
is more difficult. Tablets are not a particularly powerful stove fuel, and are sensitive to wind and damp. They are expensive and less widely available than alternatives such as alcohol or petrol.
Esbit's Material Safety Data Sheet states combustion can develop Formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...
, Ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, Nitrogen oxide
Nitrogen oxide
Nitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...
, Hydrogen cyanide and ingestion may cause Nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, Vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, Gastrointestinal disturbances, Kidney damage. When burned, the chemical oxidation of the fuel yields noxious fumes, requiring foods being cooked to be contained in a receptacle such as a pot or pan, and burned tablets will leave a sticky dark residue on the bottom of pots. If they are stored or used under damp conditions then they can break up while burning and shed burning fragments.