surface coatings

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© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free. Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition To protect – stops steel corroding, timber rotting To decorate – improves appearance, special effects To sanitise – more hygienic, easier to clean To identify – pipework and other items Why apply coatings?

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Page 1: Surface coatings

© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free.

Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition

To protect – stops steel corroding, timber rotting

To decorate – improves appearance, special effects

To sanitise – more hygienic, easier to clean

To identify – pipework and other

items

Why apply coatings?

Page 2: Surface coatings

© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free.

Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition

Paint is either water-based or solvent-based. It consists of three parts:• thinner• binder• pigment.

Paint

Page 3: Surface coatings

© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free.

Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition

Evaporation – the water/solvent component evaporatesOxidation – the paint reacts with oxygen in the airCoalescence – binder particles fuse together into a film

How does paint dry?

Page 4: Surface coatings

© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free.

Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition

Mixing a two-pack coatingAlways • follow the manufacturer’s

recommendations • use the correct ratio of base to

hardener • be aware of the mixture’s pot

life.

What does the term ‘pot life’ mean?

Page 5: Surface coatings

© Pearson Education Limited, 2008. Copying permitted for the purchasing institution only. This material is not copyright free.

Painting and Decorating NVQ and Technical Certificate Level 2, 2nd Edition

Surface coating defects