White coating system on hardwood for exteriors is always a challenging process in joinery industry. Sometimes the customer’s request for a superior aesthetical finishing goes in direct contrast with the need to preserve characteristics and durability of the wooden item. The use of Hydroplus AML3905/13 in association with pigmented sealer and topcoat of the Sayerlack range allows the perfect combination of excellent appearance and durability of the timber exposed outside. AML3905/13 is a flow coating insulator that solves the problem of tannin exudation and yellowing due to the extractives. By wetting perfectly and deeply into the grain of the hardwoods, this new insulator allows a perfect sealing of the pores, so the extractives get blocked and the timber itself becomes perfectly insulated, in combination with low fiber raising. Moreover, its wetting and penetration properties make the product the ideal primer for adhesion to the substrate and with other layers. After drying it’s possible to proceed with the usual coating system, including white primer and topcoat, in order to reach the final outstanding build up and smooth appearance.