Brush or roller.
Once the surface is prepared, apply 2-3 coats of undiluted Aqua Varnish, ensuring product is applied in thin even layers, at intervals of 4-6 hours to avoid adhesion problems. On very porous or absorbant surfaces you may need more coats. If more than 24 hours have transcurred between each coat application, sand between coats to remove dust nibs and to provide good enough adhesion for the next coat. For more information consult TDS.
