Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Learning Outcome 4 Know about selecting materials

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Timber conversion Conversion is sawing of a log into boards or planks. There are four main methods of conversion: ●Through and through ●Tangential ●Quarter ●Boxed heart

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Timber conversion: Through and through and tangential Through and through – simplest and most economical; board prone to shrinkage and distortion Tangential – used for floor joists and beams as it is very strong

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Timber conversion: Quarter sawn and boxed heart Quarter sawn – best quality timber but most expensive Boxed heart – radial sawing used when the heart of the tree is rotten

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Seasoning of timber Timber from newly felled trees has a high proportion of moisture. This must be removed. The main reasons for seasoning are: ●Make sure shrinkage happens before timber is used ●Make sure moisture content is below 20% ●Dry timber is stronger ●Dry timber is less likely split or distort

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Kiln seasoning For kiln drying: ●Air circulation supplied by fans ●Heat supplied by heating coils ●Humidity raised by steam sprays How is a progressive kiln different? What other method can be used?

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Classifying and identifying timber Timber is either: ●Hardwood ●Softwood This refers to botanical differences and not the strength of the timber. To identify timber it is useful to have a personal collection of small samples. How many types of timber do you know? Research what each is used for.

Unit 1004 Produce basic woodworking joints © Pearson Education 2010 Printing and photocopying permitted Manufactured boards Most common manufactured boards are: ●Plywood – thin layers of timber (veneers) glued together and graded by type of glue ●Laminated boards – strips of wood laminated together and sandwiched between veneers ●Chipboard – compressed wood chips and flakes bonded with a synthetic resin glue ●Fibre board – pulped wood mixed with adhesives and pressed into sheets (hardboard, softboard, MDF)