What is veneer?
Veneer is a thin slice of a tree,
which is used to decorate a lesser but more stable species by laminating the
two together.
Leaf.
One slice of veneer.
A complete matching set of veneers
stacked in the original cutting sequence.
The pattern formed by a particular
cutting sequence, or due to a freak location or climatic condition. The following are some of the more common
terms used to describe specific veneer figures. Most are self-explanatory; bee's wing, fiddle back, curly,
interlocking, cathedral, lace.
This is the centre, more dense area
of the tree. It is usually identified
as the darker, harder area of the leaf.
This is the latest growth area of
the tree and in most cases is lighter in colour and softer.
Two leaves sliced in sequence placed
one upon the other, the top leaf is then opened like a book and positioned next
to the lower leaf and joined at their corresponding edges.
Two leaves sliced in sequence placed
one upon the other, the top leaf is slipped sideways and joined to the lower
leaf at their corresponding edges.
Four leaves in sequence placed 1-4
on top of each other 1&2 and 3&4 are book matched. The two sets are then also book matched on
their narrow sides all edges positioned like 4 squares within a square. Six, eight and ten way matches are also done
in basically the same way.
Veneer is made in three ways:
1.
The first and the most common is 'slicing'. The log is cut into a square and left to
soak in 160oF water for up to 24 hours depending on the
species. The log, up to 12ft long, is
then held horizontally in a vice like fixture. A razor sharp blade then vertically slices the log into
veneer. With each stroke the log is
indexed forward at a preset distance establishing the thickness.
2.
The second method is 'roll cutting'. This procedure is primarily used to make
plywood however specific figures such as bird's-eye maple and olive ash are
best revealed in this manner. The log
is debarked, soaked in hot water then placed in a huge slow turning lathe. A long knife edge is placed against the log
face and it is trued round, then the knife begins to peel off the veneer
indexing forward with each revolution.
3.
The third and not so common is by 'sawing'. Unlike the previous methods the log is not
soaked. A large band saw is used to cut
the leaves. This method is most often
used to cut speciality veneers where there are low production
requirements. It is also the most
common method used to cut very hard, delicate burls or logs filled with
silica. Species such as satinwood,
which owes much of its lustre to silica quickly dulls the steel knives. Other species such as ebony and lignum
vitae, which are so dense that they will not float, chip unless the knife blade
is very sharp.
Terms used to describe the
Grain Figure
Veneer is cut from the log in many
ways and presents a recognizable different figure depending at what angle the
tree is sliced. If you visualize the
tree construction as being a roll of paper wrapping vertical straws within each
turn. It can be seen that a slice
through the roll at 45o, will yield a series of ovals or flakes, as
the straws are cut. Cathedral like
curves are formed when flat cut. This
knowledge is used to establish a series of predictable grain figures. The following are these terms:
Flat
cut / Rift cut / Crown cut
Sliced along the length at 90o
showing a central 'cathedral figure' in the centre and straight parallel lines
on each side.
The log is first cut in four
quarters the full length through the centre.
The veneers are now sliced along the radial face of each quarter
section. The figure consists of mostly
parallel lines becoming wider over the width of the leaf.
Roll cut / Bird's-eye
figure / Plywood
Bird's-eye figure is created by
annular growth ring distortion due to an infection, which is continued on every
new ring formation. To reveal the
figure the log is rotated against a knife and indexed inward with each
revolution. Once this was a rare
occurrence, now demand has resulted in intervention to infect the tree, usually
sugar maple but often oak and cherry.
Roll cutting is also the method used to manufacture most plywood.
Fancy or Exotic Figures
Burls are those growths usually seen
on the sides of a tree trunk which they are for want of a better comparison a
tree tumour. The grain although
exhibiting the basic characteristics of the tree has been scrambled into a
blistered bird's-eye figure. This burl
figure will also vary in colour being several shades darker than the uninfected
part of the tree. Burls are usually
flat sliced or sawn and depending on the species can be as large as 4 feet by 8
feet.
As the name implies this figure is
revealed by slicing through the face of the branch, the figure when cut is referred
to as flame (i.e.: flame mahogany or flame walnut).
After the main veneer bearing lumber
has been removed, the tree stump is pulled, trimmed and squared. The squared block is then flat sliced. The veneer figure displayed is a wild
mixture of heart and sapwood, second only to a burl.
This figure takes its name from its
most popular use, which uses sycamore or European maple with this figure for
the backs of fiddles (violins). This
figure looks three dimensional and will present washboard like ripples at 90o
to the grain line. It is usually
believed that a tree which buttresses itself against north winds will have
compressed annular growth rings in the area facing north and expanded rings
facing south. The stress in the
compressed rings is believed to cause the fiddle back figure.
The most common veneer where this
figure is present is sugar maple. It is
caused by an infection which affects the current growth ring and can be likened
to a skin disorder. A mature tree may
be infected early or late in its life and as such the figure is best revealed
by roll cutting the log until the figure disappears.
This has the effect of scales
sometimes up to 3 inches around which connect to each other. Often only a small area of the veneer will
be quilted while others will have the entire surface. Like many other figures there is no definite conclusion as to
their formation however they are highly prized and can multiply the value of
the conventional figure by many times.
Among the most common species to exhibit this figure are maple and
mahogany which is called 'pomelle' when quilting occurs.
This is a strange figure and as the
name implies appears to have been pecked by some bird, leaving darkened marks
over the surface. It is much like the
bird's-eye figure and is also caused by the infection of the annular growth ring,
It is then usually roll cut to reveal the figure. When one species, the Scandinavian birch exhibits this figure, it
is called Karelian or Masur birch. It is a pinkish white veneer with dark brown
peck marks over the entire surface.
Another North American veneer which often displays this figure is pecan.
This figure also draws its name from
its comparison to a bee's wing. The
figure is made up of an interlocking pattern of distorted rectangles which are
slightly darker on their perimeter than at their centre. This mottled effect gives the surface an
appearance of depth. It is an extremely
busy figure and is usually used as a cross-banding for borders.
This figure most often is available
only in solid lumber and is rare as veneer.
It usually seen in maple and divides the surface in trails of black
lines, sometimes very fine and others much wider, and varying shades of
grey. The figure is created by a fungus
which grows in a fallen dead tree. It
represents the first stages of decay and if allowed to continue, the wood will
become rotten and unusable.
Many woods are more fibrous than
others and will reflect light differently when viewed from different
directions. This has the effect of
changing the appearance of the surface making it appear darker or lighter. Veneers which have a very high lustre are
usually those which have a fine, tight, fibrous grain, and will exhibit a
superior figure. The term lustre
typically would apply to bee's wing satinwood or flame mahogany.
Refers to the surface to which the
veneer is glued to.
Has two meanings depending on the
context.
1.
The first refers to a method of strengthening the
substrate to prevent joins or solid wood grain orientation from transmitting
its image to the surface veneer. For
example, several solid boards joined together at their edges will eventually
begin to pull apart, pulling the face veneer with it. A quarter cut veneer of lesser species, or poor quality is first
glued to both sides of the substrate, the grain at 90o to the
joins. The face veneer will then be
unaffected by the solid wood joint expansion.
2.
The second describes a method using quarter cut veneer
to create a border or edge. In the case
of a table top the straight veneer grain is set at 90o to the edge forming a
border. In the case of an inlayed oval
or circle it will radiate from the centre around the perimeter of the design.
A private showing or preview of
an art exhibition
Vernissage has its roots in the old practice of setting aside a day before an exhibition's opening for artists to varnish and put finishing touches to their paintings -- a tradition that reportedly dates to at least 1809, when it was instituted by England's Royal Academy of Arts. English speakers originally referred to this day of finishing touches simply as "varnishing day," but sometime around 1912 we also began using the French term "vernissage" (literally, "varnishing").
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