Making Plywood
Plywood is a common building material that is used to line roofs or as wall or floor paneling. It is made by gluing together an odd number of thin layers of wood. These layers are arranged so that the direction of the grain of each layer is at a right angle to the adjacent layer. The outer layers are called faces and backs, while the inner layer is called the core. Plywood can be made from hardwood or softwood--this will determine its use. Soft plywood can be made from Douglas-fir or southern pine, while hardwood can be made from oak, birch, cherry, walnut and other woods. Interior plywood uses a moisture-resistant glue while exterior glue uses water-proof glue.
Instructions
1. Choose a log that is straight, round and ideally without knots or decay.
2. Remove the bark from the log and cut logs to the desired length. Steam-heat to soften the surface.
3. Make the veneer. This can be done by slicing, sawing or rotary cutting. Use sawing for fine finished woods, use slicing for wall panel faces or furniture and for other uses rotary cut. To slice, move the log in a flinch, against a hefty, immobile knife. To rotary cut, place in a lathe and revolve against an immobile knife that extends its length. This will cause the veneer to unwind like a ribbon.
4. Dry, trim and match the plies or layers.
5. Apply a thin layer of glue to each ply. Lay-up (or place) the layers. The grain in each layer should be opposite to the adjacent ply.
6. Squeeze together the plies using a giant hydraulic press, applying heat and pressure.
7. Finish by drying, trimming and sanding.
