Preservation of Timber
- Tar
- Paints
- Chemical salt
- Creosote
- ASCO
1. Tar: Hot coal tar is applied to wood with a brush. The tar coating protects the wood from attack by fungi and insects. This is the cheapest way to protect wood. The main disadvantage of this method of protection is that the appearance is not good after tar is applied, it is not possible to apply other attractive paints.mTherefore taring is done only for insignificant structures such as fence poles.
2. Paints: Two to three coats of oil paint are applied to a clean surface of the wood. The paint protects the wood from moisture. Paint has to be applied from time to time. Paint improves the appearance of wood. Solignum paint is a special paint that protects wood from termite attack.
3. Chemical salt: These are preservatives prepared by dissolving salts in water. The salts used are copper sulfate, masonry chloride, zinc chloride, and sodium fluoride. After treating the wood with these chemical salts, paint and varnish can be applied to achieve a good appearance.
4. Creosote: Creosote oil is obtained by distillation of coal tar. The seasoned wood is placed in an air tight chamber and the air is exhausted. The creosote oil is then pumped into the chamber at a temperature of 50 °C under a pressure of 0.8 to 1.0 N/mm2. After 1 to 2 hours the wood is taken out of the chamber.
5. ASCO: This preservative is developed by Forest Research Institute, Dehradun. This includes 1 part by weight of hydrated arsenic pentoxide (As2O5, 2 H2O), 3 parts by weight of copper sulfate (CuSO4⋅5 H2O) and 4 parts by weight of potassium dichromate (K2Cr2O7) or sodium dichromate (Na2Cr2O7⋅2 H2O). There are. ) This preservative is available in powder form. A solution is prepared by mixing six parts of this powder with 100 parts of water. The solution is then sprayed onto the surface of the wood. This treatment stops the termite attack. The surface can be painted to achieve the desired look.