 |  | Carpentry for Vocational Schools - A Teacher's handbook (GTZ, 252 p.) | ||
 |  | 19. INSIDE CLADDING | ||
|  | (introduction...) | ||
| | 19.1. Plywood painted | ||
| | 19.2. Plywood varnished | ||
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TOPIC: 19. INSIDE CLADDING
INTRODUCTION: This topic teaches students different possibilities of covering the inside walls with plywood.
OBJECTIVES: 19.1., 19.2. Students should know how plywood is nailed when it is either painted or varnished, and how to prepare it for painting or varnishing.
METHODS: 19.1., 19.2. Prepare two pieces of plywood with a straight edge and two pieces of plywood with a chamfered edge.
Show them to students and explain their advantages and disadvantages.
Explain to students how the plywood is nailed correctly and how the surface has to be before painting or varnishing can start.
Students only take notes from the blackboard.
NOTE: At the end of this topic prepare a worksheet for students to complete as homework before the next lesson.
Ensure all studs and noggings are flush with plates and that badly bowed studs have been straightened. Plywood, usually 4 mm in thickness, is fastened to frames by nails. The nails are approximately 25 mm long and jolt headed. They should be placed 200 mm apart and 10 mm from the sheet edges.
If plywood is painted it does not matter which direction the grain structure is showing. It does not make any difference if the grain structure shows horizontally like below windows or above doors. The butt end joints must fit firmly. Butt end joints can be straight or chamfered. The nails have to be punched below the plywood surface and the holes are filled with putty. When the putty is dry, sand it and apply prime coat, undercoat and finish coat.
Straight butt joint
Chamfered butt
joint
If plywood is varnished, care has to be taken that the plywood sheets are nailed only vertically and the surface of the plywood is in good condition. For nailing use 25 mm zinc-coated jolt head nails. The nails are driven just below the surface with a nail punch. The nail holes are not puttied, just sand the plywood and apply the first coat of varnish. After the first coat is dried up, sand it and apply the second coat. The joints are usually butt joints, where the edges again can be straight or chamfered.
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