Roberson's Acrylic Gold Size is an easy to use water-based 'adhesive' for metal leaf. Brush on the size to the areas to be gilded. Ready for gilding in 15-20 minutes, the size will remain open or workable for 1-2 days so a large area can be prepared before application of the leaf. For non-porous surfaces, or surfaces that have first been sealed with shellac varnish.