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Plywood and veneers
Thin veneers are used to produce plywood or can be glued onto
chipboard to make it look like a solid wood product. Logs
suitable for peeling or veneering usually attract higher prices
than sawlogs, making them the most valuable log product a
grower can produce.
Plywood veneers are peeled on a rotating lathe. Large diameter,
clean logs are preferred because of the time required to set
the log on the lathe and the fact that the core cannot be
peeled. The recent introduction of spindle-less lathes has
made it possible to peel down to a smaller core. In the production
of plywood a number of veneers are glued together with their
grain going in alternate directions to give the board strength.
Knots are generally considered a defect, especially for the
‘face’ veneers used on the outer layers of plywoods.
In some cases the knots are ‘punched out’ of the
sheets and replaced with a patch of clean veneer. Most plywood
is used for flooring, walls and concrete formwork.
The highest value timber veneers are sliced, rather than peeled,
so they show the same grain characteristics as sawn timber.
Large sections, approximately 25 centimetres square, are cut
from large clean logs. These are then put on a slicing machine
that is used to plane off sheets of veneer. Sometimes the
sections are steamed prior to slicing to ensure they cut cleanly.
The thin sheets can be dried immediately. One large, clean
log can produce acres of veneer for use in panelling and cabinetwork.
Because the sliced and rotary veneer log market is relatively
small in Australia it is fortunate that a good veneer log
is also commonly considered a good sawlog. Growers who manage
their forests for high value sawlogs may be able to take advantage
of lucrative veneer markets if they are available at the time
of harvest.
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