Wood Bending by Chemical Softening

Did you hear about wood bending without steam or with chemical? Today, I will discuss about wood bending tricks with chemical for furniture manufacturing industries. A lot of renowned contemporary furniture manufacturing companies are using these confidential tricks. Every company is using his own confidential tricks. They never share it to anybody. But I will try to give you a basic idea about this technique so that you can research on it and can apply in your contemporary furniture manufacturing field.

In this type of wood bending method, different types of chemical are used to soften the wood before bending. Some of the very common instances of chemical softening in wood bending process are alkali treatment, ammonia treatment (ammonia water, ammonia gas, and liquid ammonia), etc. Let us see the Alkali Softening at first.

Alkali softening Process for Wood Bending

Generally, in Alkali Softening Process for wood bending, Kalium Hydroxide (commercial name- Caustic potash), Natrium Hydroxide (commercial name-Caustic soda), etc are the alkali chemicals used to plasticize the wood. All these types of chemicals are normally used in a solution form. In this way, the softening process may be done in a room temperature and normal pressure and there is not necessary to provide special types of device and any heat source. Furthermore, just once the wooden material is applied with the alkali chemicals, the softness (ductility) of the material is being maintained as long as the water (moisture) is remained there. Yet, when the wood becomes dry, add water again to make the wood to become soft again. The weakness of this chemical softening method is that the chemical changes the color of the wooden material. Some timbers may not change but most of the timbers goes to change its color after softening. The thickness of the wooden material suitable for this method is between 10-20 mm. It means that the range of use of this chemical softening method is limited.

The reason behind the wood to become like plastic (becomes ductile) after the chemical softening is that the fiber (cellulose) of the wood which is straight in the usual condition contracts. It causes the wood structure to loose, and therefore, it makes the wooden material easier to bend. Furthermore, the effect of shrink/contract occurs only if the concentration of the alkali chemical is between 6-10% for caustic soda (NaOH) and 10-20% for caustic potash (KOH).

Preparing for the Alkali Solution for Chemical Softening

It is better to use the caustic soda as it is very cheap and easy to obtain. At first, prepare a caustic soda solution with a concentration between 10-15%. Try to dissolve 10-15 parts of caustic soda, NaOH to 90-85 parts of water,H2O in weight proportion and in case of caustic potash solution, make the concentration of the solution to about 10-20%.

Process Summary of Alkali Chemical Softening

  1. Dip the Wooden Material/Wood Strip into the chemical solution to penetrate the chemical.
  2. Then, bleach wood.
  3. After that, take it out from the alkali solution and keep it into the 3-5% hydrogen peroxide solution and again bleach (it could be skipped also).
  4. Next, wash it with fresh water.
  5. Finally, start the bending of wood until it is dried.

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