Seals severe stains caused by water, fire, or smoke damage; blocks knots and sap streaks; and stops stubborn bleeding stains of any kind. This versatile formula sticks to all surfaces without sanding, dries in 45 minutes, and sands easily afterward. ALLPRIMEâ„¢ Shellac-Base Primer Stain Blocker is guaranteed under any topcoat, and will permanently seal persistent odors caused by smoke, pet accidents, food smells - even musty odors.