The sequential application of aqueous solutions of tannins derived from radiata pine bark and water-soluble metal salts was examined as a means of improving the water repellency of wood surfaces. Nine metal salts were screened in combination with tannin solutions and, based on water repellency of pretreated filter paper, four were selected for further study. The two-step application of tannin solution and copper acetate solution resulted in water repellency on paper or wood surfaces that compared favourably with that introduced by a chromic acid control treatment. Leaching studies showed that significant quantities of the metal complexes precipitated on the wood surface could be removed by water leaching. Further work is now in progress to evaluate the exterior performance and photostability of the surface pretreatments.

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