Lye and soap
Lye and soap
Wood types such as oak contain tannic acid. Lye reacts with this tannic acid. This reaction makes the color of some wood types darker. Natural soap, made of lye and vegetable oil, is a way of finishing light woods preserving their natural color. Soap is a common wood finishing in Denmark and other Scandinavian countries.
In woodworking, base or lye (sodium hydroxide) is often used to remove paint, varnish and wax from wooden furniture. By dipping the wooden furniture in a bath filled with lye, the paint, lacquer and wax become soft and release. This results in clean and natural wood.
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Low footprint Lye has a low environmental footprint compared to other synthetic finishes, because it is a byproduct of the chemical industry. Soap is lye mixed with vegetable oil, which is also environmentally friendly. |
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Toxicity As is common with other corrosives, the major safety concern with lyes is their potentially destructive effects on living tissues such as skin, flesh, and the cornea. Solutions containing lyes can cause chemical burns, permanent injuries, scarring and blindness, immediately upon contact (1).
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Non toxic It is safe once dry. |
Short lifespan needs to be reapplied frequently
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Difficult recycling Sodium hydroxide is considered a hazardous waste for the environment.
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Links
What
First step to become a lye expert: Wikipedia
Dutch lye craftmen 1 (in Dutch)
Dutch lye craftmen 2 (in Dutch with English version)
How to
How to treat wood with soap, learning from the Danes
Eco info
Lye is corrosive, let’s not lie about it (Sodium Hydroxide Material Safety Data Sheet)
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Other Finishing
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Examples on Harvestmap.org