Watco Stain Blocking Primer is a fast drying, shellac based white primer.

Excellent adhesion – even to hard, smooth substrates

Improves the surface finish and allows fewer top coats to be used

It covers and seals over difficult marks and stains which would otherwise leach through paint and show in the top coat. It will cover water marks,knots or sap marks in new wood, rust stains, felt tip pen, ink, grease, nicotine, smoke and soot stains, and is ideal for redecorating after fire damage.

Watco Stain Blocking Primer may be over coated with most common types of paint: water, oil or solvent based. It is designed to be used internally, but it may also be used as a spot primer in exterior situations, for example to cover knots and sap streaks.

Coverage approx. 12m² on smooth surfaces per 1 litre per coat.

Surface preparation
Ensure all surfaces are clean, dry and free from dust, grease and oil, unsound and friable coatings and adhesives such as wallpaper adhesive. Fill cracks and holes and remove dust. Rusty surfaces must be sanded clean, followed by a spot application of Watco Red Oxide Primer which should be allowed to dry. Spot prime bare steel and other metals before applying Watco Stain Blocking Primer to the main area. Lightly sand exposed wood, and ensure any mould or mildew is removed.

Application

Apply by brush or short pile roller at temperatures above 5°C. Spray application is not recommended. Stir well before using, do not thin and do not apply too thickly to avoid drips and runs. One coat only is normally required, but two coats may be needed on very porous surfaces.