The document discusses primers and sealers used in preparing surfaces for decoration. It explains that knotting solution is used to seal resin in bare timber knots before painting to prevent staining. Knotting solution comes in shellac, patent, or white varieties. The document also outlines different types of primers that seal and protect surfaces, including acrylic, universal wood, universal metal, alkali resisting, and aluminum primers.

1. Level 1 Diploma in Painting and Decorating
© 2013 City and Guilds of London Institute. All rights reserved. 1 of 4
PowerPoint
presentationPrimers and sealers
Unit 117: Preparing surfaces for decoration

2. Level 1 Diploma in Painting and Decorating
© 2013 City and Guilds of London Institute. All rights reserved. 2 of 4
Knotting solution
Where is it used?
Knotting solution is used on bare timber that requires knots in the
timber to be sealed prior to decorating. Failure to do this will result in
the resin seeping from the knot and staining the paintwork.
Different types
It comes in three types:
• Shellac
• Patent
• White knotting
What do you think it is made from?

3. Level 1 Diploma in Painting and Decorating
© 2013 City and Guilds of London Institute. All rights reserved. 3 of 4
Types of primer
Primers are important as they seal and protect the surface.
Failure to prime the surface will result in the paint system breaking
down and the surface rotting or rusting.
• Acrylic
• Universal wood
• Universal metal
• Alkali resisting
• Aluminium

4. Level 1 Diploma in Painting and Decorating
© 2013 City and Guilds of London Institute. All rights reserved. 4 of 4
Any questions?