Gellner Wonderblock

A major cause of staining comes from water soluble chromophoric compounds like tannin. Until now water was the enemy for stopping the tannin from migrating to the surface and causing unsightly stains. The amount and the composition of tannin in wood are not uniform. The species of the tree and region that it was grown in will designate the amount of penta-metadigalloylglucoside that is contained in the wood. Penta-meta-digalloylglucoside is a derivative of gallic acid, a colorless solution that turns brown when it comes in contact with air. When ordinary or so called water borne stain blocking primers solubilize the tannin, they migrate to the surface and cause yellow or brown stains. Wonderblock forms a resistant barrier to water soluble tannins and prevents topcoats from staining and retarded drying. A compliant, 21 grams/liter VOC primer can be formulated with Wonderblock.