Power tools and abrasives 3

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Level 2 Diploma in Painting and Decorating

Power tools and abrasives

sentation

Unit 215: Preparing surfaces for decoration



Learning outcomes •  Know how to rectify surface conditions and defects. •  Know how to repair and make good surfaces. •  Know how to prepare trowelled finishes and plasterboard ready to

receive finishing systems. •  Know how to prepare timbers and timber sheet products ready to

receive finishing systems.



Orbital •  Whole sanding plate moves in small circle

causing each grain of abrasive to move likewise.

•  Most common type of electric sander available.

•  Available with rectangular, square or round base plates.

•  When using an orbital sander, there is no need to worry about the direction of wood grain.

Types of sander



Belt •  Generally removes material more quickly

than orbital sanders. •  Can make light work of sanding but

generally harder to achieve as good a finish as with an orbital sander.

•  Difficult to handle, can easily go against the grain.

215.5

Types of sander



Rotary •  The whole sanding disc goes round. •  The outer edge moves faster than the

centre, so the surface is subjected to varying degrees of sanding.

Types of sander



Palm •  Useful tool that fits into the palm of one

hand comfortably. •  Relatively light, easy to control and

cheap. •  The abrasive sheet is normally fixed to

the pad with velcro, which means it can be replaced easily.

•  They are quite small and have a triangular shape to the pad, so they can be used to sand into corners.

Types of sander



Power tools

Task

1.  Discuss in groups the safety implications when using power tools.

2.  Discuss the advantages and disadvantages of using various power tools.



Abrasives

The term abrasive paper is used to cover a variety of grit on flexible backing sheets, and it is used to smooth many types of material including timber, metal, plaster etc.

Task

List the components that require abrading in the workshop.



Abrasives Glass paper

•  Made from crushed glass bonded to a special backing paper.

•  Best for sanding bare wood (including manmade boards) but can also handle fillers of various sorts.

Aluminium oxide paper

•  Made from bauxite and is bonded to a cloth backing, which performs well on previously painted areas and bare surfaces.

•  Tends to be sharper than glass or garnet paper.

•  It does not clog.



Abrasives

Silicone carbide paper •  Better known as wet and dry. •  When wet it is primarily used for rubbing down. •  Using water as the lubricant it cuts through and breaks down the

painted defective areas, such as sags and runs. Emery paper •  Made from a natural mineral, carborundum, which is fused onto a

paper or cloth backing. •  Used with a degreaser as an abrasive for cleaning metals. Task Give examples of the degreasing agents available in the construction industry.



Abrasives Garnet paper •  Made from less pure particles of garnet (the precious stone). •  It is harder than glass and is more suited for use on hardwoods. •  The grain clogs easily if used on softwoods.

Steel wool

•  Used for the cleaning, preparing and maintaining of wood and metal finishes.

Task

Discuss in groups grades available for use in the construction industry.



Questions

1.  Which power tool is best used for abrading large surfaces such as floors?

2.  List two safety considerations when working with power tools.

3.  Which abrasive can be used wet or dry?

4.  Which abrasive used with a degreaser can be used to clean metals?



Any questions?

Education

Power tools and abrasives 3