Linseed oil

Linseed oil, also known as flax seed oil or simply flax oil, is a clear to yellowish drying oil derived from the dried ripe seeds of the flax plant ("Linum usitatissimum", Linaceae). It is obtained by pressing, followed by an optional stage of solvent extraction. Cold-pressed oil obtained without solvent extraction is marketed as flaxseed oil.

Uses

Paint binder

Linseed oil is the most commonly used carrier in oil paint. It can also be used as a painting medium, making oil paints more fluid, transparent and glossy. It is available in varieties such as Cold Pressed, alkali refined, sun Bleached, sun thickened, and polymerised (stand oil).

Putty

Glazing putty, consisting of a paste of chalk powder and linseed oil, is a traditional sealant for glass windows that dries hard within a few weeks and can then be painted over.

Wood finish

When used as a wood finish, linseed oil does not cover the surface as varnish does, but soaks into the (visible and microscopic) pores, leaving a shiny but not glossy surface that shows off the grain. Wood treated with linseed oil is resistant to denting and scratches are easily repaired, but the wood and oil surface is not as hard as a modern varnish, and it slowly absorbs moisture if allowed to stay wet. Soft wood benefits from the protection from denting but requires more applications and even more drying time than harder wood does, if the grain is to be completely filled. The oil penetrates deeply and fills the grain, because it dries slowly and shrinks little or not at all on hardening. Like other oil finishes Garden furniture treated with linseed oil may develop mildew. Linseed oil is not completely denatured, so it can encourage rather than discourage mildew growth. Oiled wood is yellowish and darkens with age.

It is a traditional finish for gun stocks, but a very fine finish may require months to obtain. Several coats of linseed oil is the traditional protective coating for the raw willow wood of cricket bats, and thus has a special cultural place in cricket-playing countries.

Fire departments treat the wood handles of hand tools that have metal implements (axes, plaster hooks etc.) on them with Linseed oil as it does not create static electricity, unlike synthetic wood finishes like varnishes.

Linseed oil is often used by billiards/pool cue-makers for the shaft portion of the cue.

Linseed oil is also commonly used as a lubricant/protectant for wooden recorders.

Nutritional supplement

Food-grade flaxseed oil is cold-pressed, obtained without solvent extraction, and marketed as edible flaxseed oil. Fresh, refrigerated and unprocessed, linseed oil is used as a nutritional supplement. It contains high levels of omega-3 fatty acids, especially alpha-linolenic acid, which has been suggested to be beneficial for reducing inflammation leading to atherosclerosis, [cite web
url=http://www.flaxcouncil.ca/english/pdf/FF_Atheroscleros_R3.pdf
work=New Flax Facts
title=Flax Reduces Inflammation Leading to Atherosclerosis
author=Diane H. Morris
publisher=Flax Council of Canada
format=PDF] preventing heart disease and arrhythmia, [cite web
url=http://www.flaxcouncil.ca/english/pdf/FF_Arrhythmia_R.pdf
work=New Flax Facts
title=ALA and Other Omega-3 Fats May Protect Against Arrhythmia
author=Diane H. Morris
publisher=Flax Council of Canada
format=PDF] and is required for normal infant development. [cite web
url=http://www.flaxcouncil.ca/english/pdf/FF_omega_R3.pdf
work=New Flax Facts
title=Omega-3 Fats Are Essential For Infants
author=Diane H. Morris
publisher=Flax Council of Canada
format=PDF] However recent well-controlled placebo studies suggest that regular consumption of flax seed oil may not reduce the risk of stroke, heart disease, or cancer any greater than placebo. [cite news
url=http://www.timesonline.co.uk/tol/news/uk/health/article694908.ece
publisher=Times Online
date=March 24, 2006
author=Nigel Hawkes
accessdate=2008-01-24
title=The benefits of fish and linseed oils as elixir of life are another health myth] Regular flaxseed oil contains between 52 and 63 % alpha linolenic acid (C18:3 n-3). Plant breeders have developed flaxseed with high alpha linoleic acid content (70 %) and very low alpha linolenic acid content (< 3%). [cite book
author=Thompson, Lilian U and Cunnane, Stephen C. eds
title = Flaxseed in human nutrition. 2nd ed.
publisher = AOCS Press
year = 2003
pages = 8-11
isbn = 1-893997-38-3]

Although flax seeds themselves contain lignans, a class of phytoestrogens considered to have antioxidant and cancer preventing properties,cite web
url=http://www.flaxcouncil.ca/english/index.php?p=g1&mp=nutrition
title=Flax - A Healthy Food
publisher=Flax Council of Canada
accessdate=2008-01-24] [cite web
url=http://www.flaxcouncil.ca/english/pdf/Flx_FctSht_SmartChoice_R3.pdf
title=Flax - A Smart Choice
work=New Flax Facts
author=Diane H. Morris
publisher=Flax Council of Canada
format=PDF] [cite web
url=http://www.umm.edu/altmed/ConsSupplements/FlaxseedOilcs.html
title=Flaxseed Oil
publisher=University of Maryland Medical Center
date=April 2002
accessdate=2006-11-12] the extracted linseed oil does not contain the lignans found in flax seed, and therefore does not have the same antioxidant properties. In fact, flax seed oil is easily oxidized, and rapidly becomes rancid with an unpleasant odor unless refrigerated. Even when kept under cool conditions it has a shelf life of only a few weeks. [cite web
url=http://www.flaxseedoil.ws/capsule.php
title=Flax Seed Oil Capsules
publisher=Flax Seed Oil
accessdate=2008-01-24] ] [cite web
url=http://www.busywomensfitness.com/flax-seed-oil.html
title=Flax Seed Oil
publisher=Busy Women's Fitness
accessdate=2008-01-24] Oil with an unpleasant or rancid odour should be discarded. Rancid oils contribute to the formation of free radicals and may be carcinogenic. [cite web
url=http://www.sentienttimes.com/02/aug_sept/flaxT.html
publisher=Sentient Times
date=August/September 2002
accessdate=2008-01-24
title=Flax Seed
author=Rebecca Wood] [cite web
url=http://www.drweilselfhealing.com/show_document.asp?iDocumentID=453&iBDC=5436&iPageNumber=1
publisher=Dr. Andrew Weil's Self Healing
title=Get the Facts on Flax
month=September | year=2006
accessdate=2008-01-24] [cite web
url=http://www.drweil.com/drw/u/id/QAA326631
title=Are Nuts a Healthy Nibble?
author=Dr. Andrew Weil
date=May 31, 2005
accessdate=2008-01-24] Oxidation of flax seed oil is major commercial concern, and antioxidants may be added to prevent rancidification. [cite journal
doi= 10.1016/j.jfoodeng.2005.03.042
title=Studies on a natural antioxidant for stabilization of edible oil and comparison with synthetic antioxidants
journal=Journal of Food Engineering
volume=74
issue=4
month=June | year=2006
pages=542–545
author=D. Berab, D. Lahirib and A. Naga ]

Nutrient content

Nutrition information from the Flax Council of Canada.

Per 1 Tbsp (14 g)
* Calories: 124
* Total fat: 14g
* Omega-3: 8g
* Omega-6: 2g
* Omega-9: 3g

Flax seed oil contains no significant amounts of protein, carbohydrates, or fibre.

Additional uses

* Animal feeds
* Sealants
* Caulking compounds
* Linoleum
* Earthen floors
* Adobe
* Textiles
* Bicycle maintenance as a thread fixative, rust inhibitor and lubricant
* Leather treatment
* Polishes, varnishes and oil paints
* Composition ornament for moulded decoration
* Animal care products
* Wood preservation
* Industrial Lubricant

Boiled linseed oil

Boiled linseed oil is used as a paint binder or as a wood finish on its own. Heating the oil makes it polymerize and oxidize, effectively making it thicker and shortening the drying time. Today most products labeled as "boiled linseed oil" are a combination of raw linseed oil, petroleum-based solvent and metallic dryers. The use of metallic dryers makes boiled linseed oil inedible. There are some products available that contain only heat-treated linseed oil, without exposure to oxygen. Heat treated linseed oil is thicker and dries very slowly. These are usually labeled as "polymerized" or "stand" oils, though some may still be labeled as boiled.

Spontaneous combustion

Rags dampened with boiled linseed oil are considered a fire hazard because they provide a large surface area for oxidation of the oil. The oxidation of linseed oil is an exothermic reaction which accelerates as the temperature of the rags increases. If rate of heat accumulation exceeds the rate of dissipation, this reaction may eventually become sufficiently hot to cause spontaneous combustion of the rags. Linseed oil soaked rags should never be stored in an enclosed container. Instead rags should be washed, soaked with water, or incinerated. A fire that destroyed the El Rey Theater-Golden West Saloon in February 2008 was ignited by the spontaneous combustion of linseed oil soaked rags left in a plastic container. [ [http://kob.com/article/stories/S363809.shtml?cat=504 KOB.com - Oil-soaked rags to blame for saloon fire ] ]

See also

* Flax seed
* National Linseed Oil Trust

References