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Woodworkers
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Wenge
(Millettia
laurentii)
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| Common
Names: |
|
Awoung
Dikela
Mibotu
Bokonge
Tshikalakala
Nson-so
Palissandre du congo
Wenge
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- Mechanical Values
| Category |
Green |
Dry |
Units |
| Weight |
72 |
57 |
lbs/cu.ft. |
| Density (air-dry) |
|
54 |
lbs/cu.ft. |
| Specific Gravity |
|
|
|
| Hardness |
|
1630 |
lbs |
| Stiffness |
2060 |
2360 |
1000 psi |
| Bending Strength |
12500 |
19500 |
psi |
| Shearing Strength |
|
2430 |
psi |
| Max. Crushing
Strength |
6300 |
10300 |
psi |
| Work to Maximum Load |
|
|
|
| Radial Shrinkage
(G->OD) |
|
3 |
% |
| Tangential Shrink.
(G->OD) |
|
6 |
% |
| Volumetric Shrink
(G->OD) |
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- Environmental
Profile
This species is reported to be rather secure with
very little threat to its existence within most of
its growth range, including Congo, but it is
officially classified as either Extinct, Endangered,
Vulnerable, or Rare in Cameroon. Its status is
listed as unknown because of inadequate information
in Gabon and Zaire (Source - World Conservation
Monitoring Center - 1992).
Distribution
The natural growth range of the species is reported
to be the open forests of Zaire, Cameroon, Gabon,
the southern regions of Tanzania, and Mozambique. It
is also found in the swampy forests of the Congo
region.
Product Sources
Some lumber from this species is reported to be
available from sustainably managed or
environmentally responsible sources.
The International Tropical Timber Organization (ITTO)
reports that timber from this species is produced
regularly but it is exported only in low volumes.
Wenge is reported to be always in limited supply on
the US market. Some reasons for this are low yield
from logs because of high waste from "mulot"
or "heavy worm" infestation, supply
problems from sources in Africa, and less demand on
the market for darker colored woods. The wood is
reported to be used almost exclusively for
architectural purposes such as paneling and
furniture pieces. Suppliers are reported to to be
offering Wenge more frequently in recent years.
Prices are reported to be often in the high range.
The following species in the database is reported to
have characteristics that are similar to those of
Wenge:
Wacapou (Vouacapoua americana )
Aramatta (Diplotropis purpurea )
The following species in the database has been
suggested as a good substitute for Wenge:
Pao rosa (Swartzia fistuloides )
Tree Data
The tree is described as medium sized, and attains a
height of 50 to 60 feet (15 to 18 m) and a trunk
diameter of 30 to 36 inches (75 to 100 cm).
Sapwood Color
The sapwood is pale yellow or whitish in color, and
is clearly demarcated from the heartwood.
Heartwood Color
The heartwood is dark brown, mostly black, with
fine, closely spaced, very dark veins and white
lines. The combination of white bands against the
dark wood with black streaks gives Wenge a very
attractive appearance. Color variation between
boards is reported to be moderate.
Light & Air-Induced Changes
Exposure lightens the dark color of the wood, and
lumber is reported to be occasionally left in the
sun on purpose to lighten the color (sometimes
requested by importers of Wenge).
Grain
The grain is fairly straight to slightly roey. The
appearance of the wood has been described as
expressive.
Texture
The wood is medium to coarse in texture.
Odor
There is no distinctive odor or taste.
Luster
Luster is reported to be low.
Ease of Drying
The wood is fairly difficult to dry. It seasons
slowly, and a fair amount of care is required in
order to avoid or reduce drying defects.
Drying Defects
The material has a high tendency to check during
drying. There is also a slight chance of distortion.
Kiln Schedules
T6 - D2 (4/4); T3 - D1 (8/4) US
Movement in Service
The wood is rated as fairly stable, but there are
reports of significant movement in use in actual
installations.
T/R Ratio
2.00
This indicator is more meaningful if it is used
together with other drying information and actual
shrinkage data in the tangential and radial
directions. (Refer to the Numerical Values window).
Natural Durability
The heartwood is reported to be durable and is
resistant to termites.
Resistance to Impregnation
The heartwood is reported to be highly resistant to
preservative treatment but the sapwood is treatable.
Natural Growth Defects
Brittleheart is sometimes present in the wood, as
are bore holes. The latter tends to reduce the
volume of quality material from logs.
Weathering
Resistance to the harmful effects of the weather is
reported to be high, which makes Wenge suitable for
some exterior applications.
Toxic Constituents
Sawdust from machining operations is reported to
cause dermatological and respiratory problems in
some individuals.
Veneering Qualities
The porous nature of the wood is reported to make
Wenge a rather difficult wood to slice. It requires
smooth cutting, and quality material is reported to
be rather difficult to obtain. Wenge is reported to
be too heavy to be used for plywood manufacture.
Blunting Effect
The wood exerts medium blunting effect on cutting
tools.
Cutting Resistance
The timber is reported to saw slowly.
Planing
The timber is reported to be fairly easy to work
with machine tools.
Turning
Wenge is reported to be popular as a good turnery
wood.
Gluing
The material is reported to be rather difficult to
glue because of the presence of resin cells.
Nailing
The timber is described as tough and strong, and
requires pre-boring in nailing, but holding
characteristics are reported to be good.
Sanding
Sanding characteristics are reported to be
satisfactory.
Polishing
The wood is reported to be rather difficult to
polish, but satisfactory polishing results can be
obtained after filling.
Varnishing
Varnishing properties are reported to be rather
poor. Some solvent-based stains are reported to dry
with difficulty.
Response to Hand Tools
The wood responds well to hand tools.
Strength Properties
Strength properties of the timber are reported to
vary with density, but bending strength in the
air-dry condition is generally very high. Strength
qualities in compression parallel to grain are
exceptionally high. It is moderately hard and
resistant to wearing and marring. Weight and density
are very high. Wenge is reported to be a suitable
substitute for Hickory (Carya ) for the production
of sporting goods.
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