In this study, the long-term (5-year) performances of 2 varnish systems, semitransparent alkyd-based brown stain (SABBS) and alkyd-based clear varnish (ABCV), were evaluated on preservative-treated Scots pine (Pinus sylvestris L.) sapwood. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2013) 37: 126-132 © TÜBİTAK doi: Adhesion properties of some protective layers exposed to outside weather conditions for five years 1, 1 2 Mehmet BUDAKÇI *, Cihat TAŞÇIOĞLU Department of Wood Works Industrial Engineering, Faculty of Technology, Düzce University, 81620 Düzce, Turkey 2 Department of Forest Industrial Engineering, Faculty of Forestry, Düzce University, 81620 Düzce, Turkey Received: Accepted: Published Online: Printed: Abstract: In this study, the long-term (5-year) performances of 2 varnish systems, semitransparent alkyd-based brown stain (SABBS) and alkyd-based clear varnish (ABCV), were evaluated on preservative-treated Scots pine (Pinus sylvestris L.) sapwood. Prior to varnish application, specimens were impregnated with 2 different types of wood preservative. The experimental variables were varnish type, layer thickness, and wood preservative. ASTM D 1641 was followed for exposing wood specimens to outdoor conditions. The effects of long-term exposure on adhesion properties of applied varnish systems were tested according to ASTM D 4541. Long-term outdoor exposure resulted in and reductions in the adhesion properties of SABBS and ABCV varnish systems, respectively. The layer thickness and preservative type did not show any statistical reductions in adhesion properties. Key words: Adhesion strength, ageing, outside weather conditions, wood preservative, varnish, stain 1. Introduction Wood material exposed to outdoor conditions without proper preservation is prone to biological and chemical degradation. While various finishing chemicals and techniques are available to prevent wood surfaces from such degradation, most applications fail due to long-term exposure to outdoor conditions. These failed finishes cannot protect the wood surfaces they .