Wood Finishing

TOPIC 5

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INDUSTRIAL TECHNOLOGY-INDUSTRIAL TECHNOLOGY-TIMBERTIMBER

ASSOCIATED THEORYASSOCIATED THEORY

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INTRODUCTIONINTRODUCTION

HOW FINISHES WORK

HOW FINISHES WORK

SURFACE PREPARATION

SURFACE PREPARATION

TYPES OF ABRASIVES

TYPES OF ABRASIVES

REPAIRING MINOR DEFECTS

REPAIRING MINOR DEFECTS

STAINING TIMBERSTAINING TIMBER

TYPES OF POLYURETHANE

TYPES OF POLYURETHANE

APPLYING POLYURETHANE

APPLYING POLYURETHANE

MISCELANEOUS FINISHES

MISCELANEOUS FINISHES

BIBLIOGRAPHYBIBLIOGRAPHY

Click on a topic or press Enter to commence.

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IntroductionIntroduction

Planning & Design

Material preparation & ConstructionApplication of a Protective Finish

There are three main stages to the successful completion of a wood project:

Stage 2

Stage 1

Stage 3

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IntroductionIntroduction

absorbentprotected

Although wood is durable and resistant to a fair

amount of wear and tear the surface is ………………..

and needs to be ………………..

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IntroductionIntroduction

stainSpilt food, dirt and hand marks tend to ……………….

and …………… the surface. dull

Water raises the grain and tends to …………….. the surface. Alternatively, excessive dehydration will

cause the timber to ……………….. and ……………...

roughen

shrink split

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If left untreated the timber fades, & cracks appear.

before

after

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How Finishes Work.How Finishes Work.

Saturating the fibres and filling the pores

A protective finish seals the surface of the timber in one of two ways.

1.

2. Bonding to the surface in a tough, flexible film.

The latter method is usually quicker as it can be performed in a single operation.

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The nature of the project, and where it will be

used will determine ………………………………

the type of finish

Outdoor projects require a finish that will

resist ………………and the effects of …………………………

moisture

ultra violet light

Indoor projects may be less durable, but are

often ……………………… and a finish is chosen

that enhances the natural ……………………………....

decorative beauty of the

timber

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This outdoor This outdoor setting needs setting needs a finish that a finish that will resist will resist moisture and moisture and ultra violet ultra violet rays. rays.

UnfortunatelyUnfortunately, nothing will , nothing will stop it from stop it from fading fading eventually.eventually.

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The quality of the finished surface depends on many factors, the first of which is good

………………………………………

surface preparation

Surface PreparationSurface Preparation

Generally, the more care taken with surface

preparation, the better will be the final……………

finish

Defects that are present on the surface will

usually show up under ………………………….

clear finishes

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Sanding:Sanding: This is the name given to the process of smoothing timber by actually “scratching” the surface with…………………………..

abrasive paper

Surface PreparationSurface Preparation

Abrasive paper was originally made from ……………, hence the term ……………………….sandin

gsand

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Abrasives consist of small particles of crushed grit that is glued to a backing sheet. The

backing sheet may be ………………. or

………………..

cloth

Surface PreparationSurface Preparation

Abrasives are made from crushed ……………,

……………… or other…………………………………

glass

paper

garnet synthetic material

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Abrasives can be wrapped around various shaped blocks for hand sanding.

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Or they can be attached to the base plate of

And orbital sanders

Belt sanders

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Abrasives are graded by number. The larger

the number the smaller ………………………………

the grit particles

Abrasives are available in sheets, or they may be

made into belts for different sanding …………………….

machines

They may also be purchased as discs or small round cylinders for special situations.

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Number

Common Use

40 Belt Sander- very coarse

80 Removing plane marks

100 Hand or orbital sanding

120 Hand or orbital sanding

180 Final hand or orbital sanding

240 Smoothing after 1st coat

320 Smoothing after 2nd coat

These are the most common “grits” used at AHS.

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On the back of the abrasive paper is information pertaining to:

The brandbrand of the abrasive

The material material used for the abrasive

The gritgrit of the abrasive

Important: Whenever possible sand in the direction of the grain of the timber.

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Important: Whenever possible sand in the direction of the grain of the timber.

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Types of AbrasivesTypes of Abrasives

TYPETYPE PROPERTIESPROPERTIES USESUSES

GARNETGARNET Orange natural mineral, friable

Softwood furniture

ALUMINIUM ALUMINIUM OXIDEOXIDE

Very tough, block shaped grit

Best all purpose woodworking abrasive

SILICON SILICON CARBIDECARBIDE

Shiny, black very hard particles

Rubbing back a polyurethane finish.

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Repairing Minor DefectsRepairing Minor Defects

Timber is a natural material, and often it is necessary to disguise natural defects before adding the final finish. In other cases it may be

necessary to repair………………………………………

poor workmanship

There are a number techniques that can be used to disguise faults in timber, but they must be

carried out …………………………………………………

before the finish is applied

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Wood putty or stopper Available in a range of timber colours, and can be pressed into small gaps and cracks.

Method Press putty into joint with clean flexible knife. Leave slightly raised. Sand off when dry.

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Matching timber colours A small amount of stain may be mixed with the putty to get a better colour match.

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Inserting a Plug Cut a hole with a plug cutter directly over the defect. Insert a plug of the same timber with the grain running in the same direction. Alternatively, insert a different coloured plug as a “feature”.

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Staining TimberStaining Timber

Timber may be stained before a protective finish is applied. This is carried out for the following reasons:

1. To even out the variations in colour that occur naturally with some timbers.

2. To make an inexpensive timber look like an exotic species of timber.

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    Brandy Stain (pine) Antique Stain (pine)

This slide and the following two slides show different stains that can be applied to pine to make it look like an expensive alternative timber.

                                         

    

                                         

    Sierra Brown Stain (pine) Provincial Stain (pine)

                                         

    

                                         

    Honey Stain (pine) Salem Stain (pine)

                                         

    

                                         

    Chocolate Stain (pine) Vintage Stain (pine)

                                         

    

                                         

    Auburn Stain (pine) Hickory Stain (pine)

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Test a small amount of stain on a piece of timber similar to your project to gauge the colour of the finish. Several stains may be tested on a “test strip”

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Staining TimberStaining Timber

Stains can be applied with a brush or a rag. Wipe along the grain and wipe off excess with smooth even strokes. Wear gloves.

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Types of Polyurethane

Oil-based, thin with mineral turps.

Oil-based gel

Water-based, clean up with water.

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Applying Polyurethane

Polyurethane may be brushed on…….

Or applied with a cotton pad.

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Applying Polyurethane

Spraying is a good method for fiddly jobs.

A foam pad or applicator is good for large flat surfaces.

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Applying Polyurethane

Lightly sand the surface between each coat using 320 grit aluminium oxide or carborundum.

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Applying Polyurethane

After the final coat has hardened Scandanavian oil or a wax can be rubbed into the surface.

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There are many other types of finishes that may be applied to timber. Some of these include….

French polishFrench polish

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There are many other types of finishes that may be applied to timber. Some of these include….

Tung oilTung oil

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There are many other types of finishes that may be applied to timber. Some of these include….

Canauba waxCanauba wax

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And of course paint.

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Bibliography & other ResourcesBibliography & other Resources

These two are available from the school library

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Bibliography & other ResourcesBibliography & other Resources

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Bibliography & other ResourcesBibliography & other Resources

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Bibliography & other ResourcesBibliography & other Resources

The end of The end of Topic 5Topic 5