Coal tar 4 See also 5 References 6 External links
"Tar" and "pitch" can be used interchangeably; asphalt (naturally
occurring pitch) may also be called either "mineral tar" or "mineral
pitch". There is a tendency to use "tar" of more liquid substances and
"pitch" of more solid (viscoelastic) substances. Both "tar" and
"pitch" are applied to viscous forms of petroleum or heavy crude oil,
technically better described as asphalt or bitumen, such as the
asphalt found in naturally occurring "tar pits" (e.g., the La Brea Tar
Pits in Los Angeles) and oil sands deposits (sometimes called "tar
sands") (e.g., the
Tar Tunnel in Shropshire). "Rangoon tar", also known as "Burmese Oil" or "Burmese Naphtha", is also a form of petroleum. Wood
Wood tar Further information: Pine tar
Pine tar and Birch tar
Tar kiln at Trollskogen in Öland, Sweden.
In Northern Europe, the word "tar" refers primarily to a substance
that is derived from the wood and roots of pine. In earlier times it
was often used as a water repellent coating for boats, ships, and
roofs. It is still used as an additive in the flavoring of candy,
alcohol, and other foods.
Wood tar is microbicidal. Producing tar from wood was known in ancient Greece and has probably been used in Scandinavia
Scandinavia since the Iron Age. For centuries, dating back at least to the 14th century, tar was among Sweden's most important exports. Sweden
Sweden exported 13,000 barrels of tar in 1615 and 227,000 barrels in the peak year of 1863. Production nearly stopped in the early 20th century, when other chemicals replaced tar, and wooden ships were replaced by steel ships. Traditional wooden boats are still sometimes tarred. The heating (dry distilling) of pine wood causes tar and pitch to drip away from the wood and leave behind charcoal. Birch bark
Birch bark is used to make particularly fine tar, known as "Russian oil", suitable for leather protection. The by-products of wood tar are turpentine and charcoal. When deciduous tree woods are subjected to destructive distillation, the products are methanol (wood alcohol) and charcoal. Tar
Tar kilns (Swedish: tjärdal, Danish: tjæremile, Norwegian: tjæremile, Finnish: tervahauta) are dry distillation ovens, historically used in Scandinavia
Scandinavia for producing tar from wood. They were built close to the forest, from limestone or from more primitive holes in the ground. The bottom is sloped into an outlet hole to allow the tar to pour out. The wood is split into dimensions of a finger, stacked densely, and finally covered tight with dirt and moss. If oxygen can enter, the wood might catch fire, and the production would be ruined. On top of this, a fire is stacked and lit. After a few hours, the tar starts to pour out and continues to do so for a few days. Uses
Tar-flavored candy, Terva Leijona.
Tar was used as seal for roofing shingles and tar paper and to seal the hulls of ships and boats. For millennia, wood tar was used to waterproof sails and boats, but today, sails made from inherently waterproof synthetic substances have reduced the demand for tar. Wood tar is still used to seal traditional wooden boats and the roofs of historical shingle-roofed churches, as well as painting exterior walls of log buildings. Tar
Tar is also a general disinfectant. Pine tar
Pine tar oil, or wood tar oil, is a pure natural product used for the surface treatment of wooden shingle roofs, boats, buckets, and tubs and in the medicine, soap, and rubber industries. Pine tar
Pine tar has good penetration on the rough wood. An old wood tar oil recipe for the treatment of wood is one-third each genuine wood tar, balsam turpentine, and boiled or raw linseed oil or Chinese tung oil. In Finland, wood tar was once considered a panacea reputed to heal "even those cut in twain through their midriff". A Finnish proverb states that "if sauna, vodka and tar won't help, the disease is fatal." Wood
Wood tar is used in traditional Finnish medicine because of its microbicidal properties. Wood
Wood tar is also available diluted as tar water, which has numerous uses:
As a flavoring for candies (e.g., Terva Leijona) and alcohol (Terva Viina) As a spice for food, like meat As a scent for saunas. Tar water is mixed into water, which is turned into steam in the sauna As an anti-dandruff agent in shampoo As a component of cosmetics
Mixing tar with linseed oil varnish produces tar paint.
Tar paint has a translucent brownish hue and can be used to saturate and tone wood and protect it from weather. Tar
Tar paint can also be toned with various pigments, producing translucent colors and preserving the wood texture. Coal
Coal tar Main article: Coal
Coal tar In English, German, and French, "tar" is a substance primarily derived from coal. It was formerly one of the products of gasworks. Tar
Tar made from coal or petroleum is considered toxic and carcinogenic because of its high benzene content, though coal tar in low concentrations is used as a topical medicine. Coal
Coal and petroleum tar has a pungent odour. Coal
Coal tar is listed at number 1999 in the United Nations list of dangerous goods. See also
^ Daintith, John. "tar". Oxford University Press (6th ed.). A
dictionary of chemistry. Retrieved 14 March 2013. "Tar:
Definition". Miriam Webster. Retrieved 14 March 2013. "a dark
brown or black bituminous usually odorous viscous liquid obtained by
destructive distillation of organic material (such as wood, coal, or
peat)". "tar and pitch" (6th ed.). The Columbia Electronic
Encyclopedia. Retrieved 14 March 2013. "tar and pitch, viscous,
dark-brown to black substances obtained by the destructive
distillation of coal, wood, petroleum, peat, and certain other organic
^ Burger, Pauline. "Ancient maritime pitch and tar a
multi-disciplinary study of sources, technology and preservation".
British Museum. Retrieved 14 March 2013.
^ "tar and pitch" (6th ed.). The Columbia Electronic Encyclopedia.
Retrieved 14 March 2013. "The terms tar and pitch are loosely
applied to the many varieties of the two substances, sometimes
interchangeably. For example, asphalt, which is naturally occurring
pitch, is called mineral tar and mineral pitch.
Tar is more or less fluid, depending upon its origin and the temperature to which it is exposed. Pitch tends to be more solid."
Look up tar, pitch, asphalt, or bitumen in Wiktionary, the free dictionary.
^ "Geotimes – February 2005 – Mummy tar in ancient Egypt". Retrieved January 9, 2006. Details history and uses of "Rangoon Tar"
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