Question Of The Month: Liability To The Subsurface

Water-thinnable lacquers often do not adhere adequately to the surface, especially if they are applied to old, silky or matt alkyd resin coatings. Why is that and how can I avoid it? Growing environmental awareness, but also efforts to avoid unpleasant smells, mean that interior water-thinnable, high-quality paint products or PUR-reinforced acrylic paints are being used for renovation on old silky and high-gloss alkyd resin coatings. Coatings with these water-thinnable lacquers are often applied without an adhesion-promoting primer, and it then turns out that there is insufficient adhesion to the substrate. In fact, coatings on old, silky or matt alkyd resin coatings are particularly at risk. The compositions of the old alkyd resin coatings differ from manufacturer to manufacturer. Waxes are often used as matting agents. These substances then prevent sufficient adhesion of the water-dilutable paint material. Tests that were carried out in the ZERO application technology have shown that an adhesion from "very good" to "poor" can be seen on silky gloss lacquers from a wide variety of European manufacturers. Since the executing painter cannot check on site how the old coating is composed, there remains a high risk that good adhesion cannot be guaranteed even after sufficient drying. An improvement in liability is achievedif the surface is sanded completely matt - however, no completely satisfactory result can be expected here either. Only an adhesion-promoting pre-coating - e.g. with a 2-component ZERO Aqua PUR primer or with ZERO Intermatt insulating and adhesive primer - has shown very good adhesion on all old coatings during internal tests. Conclusion Before selecting the appropriate paint on old silky or matt alkyd resin varnishes, the surface should always be matt sanded and primed with an aqueous polyurethane primer or insulating and primer! [email protected] 2-component ZERO Aqua PUR primer or with ZERO Intermatt insulating and adhesive primer - has shown very good adhesion on all old coatings during internal tests. Conclusion Before selecting the appropriate paint on old silky or matt alkyd resin varnishes, the surface should always be matt sanded and primed with an aqueous polyurethane primer or insulating and primer! [email protected] 2-component ZERO Aqua PUR primer or with ZERO Intermatt insulating and adhesive primer - has shown very good adhesion on all old coatings during internal tests. Conclusion Before selecting the appropriate paint on old silky or matt alkyd resin varnishes, the surface should always be matt sanded and primed with an aqueous polyurethane primer or insulating and primer! [email protected]