5.4. Other Wood-fillings
About wood-filling substances, I had already tested the following materials:
- Konyaku (also known as Devil's Tongue, a jelly made from dietary fiber of the corm)
- Persimmon Tannin
The two materials are made from vegetable and different from animal glue. Both are of time-honored traditional Japanese materials. These materials worked for wood-filling but still using size is easy, simple and convenient for plywoodgraph.
Besides, the object of my next research might be the following material:
3. Agar
5.4.1. Konnyaku
Konnyaku is derived from a perennial plant of the genus amorphophallus; native to warm subtropical to tropical eastern Asia. The corm of the amorphophallus plant is growing from a large up to 25 cm in diameter.
The main component of the corm is glucomannan, and the dehydrated corm contains around 40% it. Glucomannan is a water-soluble polysaccharide and this polysaccharide is a dietary fiber and makes sol. This sol expands with absorbing water and gives colloidal viscously highly and this colloidal solution coagulates by adding alkali and heating. This gel is konnyaku and glucomannan which coagulated with alkali once is not water-soluble and has the elasticity.
It is said that amorphophallus plant was supposedly introduced into Japan about 5000 years ago in the Jōmon period (縄文時代 Jōmon jidai: it is the time in Japanese prehistory from about 14,000 BCE to 300 BCE). It is oldest record as a cooking jelly made from the corm of amorphophallus plants that was entered in the Wamyō ruijushō (和名類聚抄, the second oldest extant Japanese dictionary) compiled by Minamoto no Shitagō (源順, 911-983 CE, a mid Heian waka poet, scholar and nobleman) at the request of an Imperial princess in the Jōhei period (also romanized as Shōhei 承平, 931-938 CE, in the middle of the Heian period). It is told that already cooking the corm of amorphophallus plants with the lye was known in those days.
Konnyaku is used for food in a part of Asia today but Japan is only one country where amorphophallus plant is widely cultivated for food. Growing the improved amorphophallus plant for agricultural products is rare all over the world. Konnyaku is time-honored Japanese original food by referring to Japanese history. This food is very low in calories with higher dietary fiber content and a very popular for health and diet in Japan in past and present.
Konnyaku liquid for wood-filling: Soak a little refined glucomannan powder in plenty of water in 1-2 hours. After strain the grains of the glucomannan powder from this colloidal solution, add Calcium hydroxide [Ca(OH)2] aqueous solution. Apply the konnyaku liquid on the surface of plywood instead of the size. Dry the konnyaku liquid securely; this gel which coagulated once is not water-soluble. However, glucomannan powder is not common a little; cannot buy it at supermarket anywhere around. In addition, dissolving glucomannan powder in the water takes time. Furthermore, it is impossible to heat the gel up for promoting the chemical reaction after applying the konnyaku solution on plywood plate; it takes time. The fresh konnyaku and konnyaku meal contain calcium oxalate [CaC2O4/Ca(COO)2] and it makes itching to skin; acetic acid would relieve this itching. It is better to use refined glucomannan powder for making the konnyaku liquid.
5.4.2. Persimmon Tannin
Persimmon tannin is an auburn semitransparent liquid and made from an astringent persimmon. This astringent persimmon is only for the persimmon tannin and it has highly astringent taste and therefore inedible.
Break unripe fruit of astringent persimmon into pieces, compress them and get juice, ferment the juice and let it mature. The persimmon tannin has a strong bad smell from acetic acid, butyric acid, and the like by fermentation; it was unfit for domestic when I used. However, odorless persimmon tannin was newly developed refined by new method recently at the end of 20th century.
Persimmon tannin is a traditional Japanese peculiar material and it has been used for diverse uses since the Heian period (平安時代 Heian jidai, 794-1185/1992) in Japan. The oldest record about persimmon tannin entered in a book is in about 10th century: persimmon tannin was used for undercoat of japanned.
Persimmon tannin has a preservative effect and this effect was applied to a mummy since old times. Besides, the strength of the materials increases by applying persimmon tannin and it makes durable. These natures of persimmon tannin were used also for a fishing net, a fishing line, undercoat before to paint on woodwork and wooden building, and mixed with ash for painting the outer wall.
As the paint, the use of persimmon tannin was decreasing but persimmon tannin is being reevaluated for Sick Building Syndrome in recent years.
Furthermore, as folk remedies, it was used for a burn, chilblains, a hypotensive and an antidote.
Applying persimmon tannin on the paper and drying it makes the paper hard and strong. This nature was used to a fan and an umbrella. This paper applied persimmon tannin is still important material for a paper pattern of dyeing.
Also persimmon tannin is used for dyestuff. It is said the origin was kakiso (柿衣) which low-class samurai had worn. This cloth dyed with persimmon tannin has disinfection effect and it was used for filtering water of a river and a well water out bacteria for drink before. Now the cloth dyed with persimmon tannin is called kakishibu-zome (柿渋染め) and the shade of brown is popular in Japan.
Tannin is a vegetable water-soluble compound, a kind of polyphenolic. The name of tannin is for a specific nature, not classified by chemical structure. Tannin binds and precipitates or shrinks proteins, alkaloid, and metal ion.
This nature of persimmon tannin is used for clarifier to remove haze-causing proteins from sake (Japanese rice wine) and persimmon tannin is used mostly for this use at the present.
Persimmon tannin for wood-filling: Apply persimmon tannin weakened with water for proper concentration on the surface of plywood board.
5.4.3. Agar
Agar might be the object for my next research.
Agar is a natural vegetable gelling agent. This gelling agent is a polysaccharide obtained from a fluid that accumulates in the cell walls of the seaweed called "red algae", and it serves as the primary structural support for the algae's cell walls. Chemically, agar polysaccharides are a polymer made up of subunits of the sugar galactose.
The melting point is at 85-90°C (185-194°F) and the solidifying point is at 35-40°C (95-104°F); therefore it needs boiling in water until the solids dissolve.
Agar was discovered by chance in Fushimi Kyoto (京都伏見) Japan, in 1685 (the 2nd year of Jōkyō貞享, the early Edo period).
Agar is made by natural freeze drying in Japanese winter. Boil dehydrated red algae with the water. Strain the stock and set the agar jelly by cooling the stock. Cut the jelly to bars of suitable shape and size. Freeze the jelly outdoors by cold temperature in night and thaw the frozen jelly by sunning in daytime. Repeat this process approximately two weeks for drying.
Agar is one of the two major gelling agents compared with gelatin in general Japanese domestic use and very popular for health and diet, chiefly used as an ingredient in desserts throughout Japan. The shape of agar is sold generally as a bar, a string and a powder and may easily get it anywhere in Japan now.
Agar is approximately 80% fiber (agarose) and this fiber content is top level in foods. Agar has both soluble dietary fiber and insoluble dietary fiber and this nature is better for an intestinal regulator.
Soluble dietary fiber dissolves in water and get pulpy in the body. This pulpy fiber wraps foods and slowly drifts into the stomach and the intestines. Therefore absorption of fat, sugar and salt is cut. It means it prevents that the blood glucose level suddenly goes up. The surplus of fat, sugar and salt is excreted wrapped with the fiber.
Insoluble dietary fiber absorbs water and triples in size on the stomach after the fiber was ingested. This nature would make eater feeling more full. This fiber drifts into the intestines not dissolved, so it makes the intestines an active peristaltic movement. Moreover, agar is calorie free.
Also as a solid substrate to contain culture medium for microbiological work, nutrient agar is typically sold commercially as a powder and used throughout the world because the basic agar formula may be used to grow most of the microbes whose needs are known.
Agar liquid for wood-filling: Agar would become soggy when wetting the surface of the plywood board, although not dissolved; therefore it is suggested that it would be physically broken by pressurization with roller and press machine. I first need to find cross-linker for agar. Cross-links are bonds that link one polymer chain to another. Besides sometimes agar does not set when it is boiled with acidic fruits; therefore, whether agar is able to withstand with acid of gum arabic is a question.