Varnished Wood Research Articles

Natural finishes for exterior timber

Untreated timber exposed to the weather will discolour and degrade under the influence of physical and biological agencies. If the natural appearance of exposed timber is to be preserved, it is necessary to apply some form of surface treatment. This digest discusses the selection, use and maintenance of exterior wood stains, varnishes and other types of external natural finish. Before considering the different types of natural finish in detail, it first deals with the characteristics of the wood substrate that have a significant influence on their performance. The digest brings up to date the information contained in an earlier (now withdrawn) digest, No. 182.

Studies on the preparation of oleo-resinous wood varnishes by utilizing safflower (<i>Carthamus tinctorius</i>) seed oil

Studies were carried out on the preparation of oleo-resinous wood varnishes by utilizing safflower (Carthamus tinctorius) seed oil. It was observed that safflower seed grown under the soil-texture and climatic condition of Bangladesh, contains about 32 % golden yellow coloured drying oil. The physico-chemical characteristics of the oil were determined by the conventional methods and the fatty acid compositions by GLC. From the results it is evident that the oil can be used suitably in paint and varnishes on account of its high linoleic acid content (75 %) and higher iodine value (148). The oleoresinous wood varnishes was prepared by utilizing safflower seed oil in an open stainless steel beaker by heating the oil with rosin and glycerol. The cooking temperature was maintained at 300O C for ½ an hour. Zinc oxide and lead oxide were used as mould growth inhibitor and catalyst respectively. The varnish thus prepared was found to be water resistant and can be applied on wood surface as tack free coating. 
 
 Bangladesh J. Sci. Ind. Res. 41(1-2), 77-82, 2006