Leadwood (Combretum imberbe)

Leadwood (Combretum imberbe)

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Common Name(s): Leadwood

Scientific Name: Combretum imberbe

Distribution: From South Africa north to Tanzania

Tree Size: 32-64 ft (10-20 m) tall, 1-2 ft (.3-.6 m) trunk diameter

Average Dried Weight: 76 lbs/ft3 (1220 kg/m3)

Specific Gravity (Basic, 12% MC): .96, 1.22

Janka Hardness: 3,570 lbf (15,880 N)

Modulus of Rupture: 20,960 lbf/in2 (144.5 MPa)*

Elastic Modulus: 2,494,000 lbf/in2 (17.20 GPa)*

Crushing Strength: 9,950 lbf/in2 (68.6 MPa)*

Shrinkage: Radial: 2.0%, Tangential: 4.7%, Volumetric: 6.8%, T/R Ratio: 2.4*

*Strength and shrinkage values are for the closely related Combretum schumannii

Color/Appearance: Heartwood is a rich, reddish brown to dark brown; color darkens with age. Clearly demarcated sapwood is a pale yellow.

Grain/Texture: Knots and other grain irregularities are not uncommon. Fine uniform texture.

Endgrain: Diffuse-porous; sometimes exclusively solitary; large pores sometimes arranged in radial/diagonal patterns, very few; heartwood mineral/gum deposits common; parenchyma vasicentric and lozenge; narrow rays, spacing fairly close to close.

Rot Resistance: Reported to be very durable, with excellent insect resistance and weathering characteristics.

Workability: Generally difficult to work on account of its density; sharp cutters must be used to avoid tearout. Can also give problems in gluing and finishing. Turns superbly.

Odor: No characteristic odor.

Allergies/Toxicity: Although there are no specific reports on Combretum imberbe, other species in the Combretum genus (particularly C. kraussii) have been reported to cause skin irritation. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.

Pricing/Availability: Not offered very often for sale, Leadwood is occasionally available as turning blanks and small lumber. Prices are likely to be high for an imported hardwood.

Sustainability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.

Common Uses: Carving, furniture, turned objects, and other small specialty items.

Comments: Smaller trees are used as fuelwood, as the wood burns slowly at high temperatures.

Related Species:

None available.

Related Articles:

Scans/Pictures: A special thanks to Rory Wood for providing the facegrain sample, as well as Steve Earis for providing the 10x engrain sample of this wood species.

Leadwood (Combretum imberbe)

Leadwood (sanded)

Leadwood (sealed)

Leadwood (sealed)

Leadwood (endgrain)

Leadwood (endgrain)

Leadwood (endgrain 10x)

Leadwood (endgrain 10x)

  • Derrick Wardhaugh

    To whom it may concern.

    We are based in Mozambique and are busy making all the windows, doors an furniture out of Leadwood, or as we know it Monzo.

    Would you be interested in some info that is missing from your site?

    Regards,

    Derrick.

  • Derrick Wardhaugh

    The timber is very strong but brittle, rigid in short lengths but not so rigid when long.
    When grading the mill must understand the way the tree grows.
    The nature of the tree is very erratic and the branches break off easily.
    Unfortunately the tree grows around the knot and often leaves cavities which are often concealed.
    It also suffers from shake, mostly at the base of the tree near the center.
    Once again dependent on the mill and their ability to understand where to look for faults.

    When machining you get a combination of fine powder-like dust and normal shavings.
    BE SURE TO USE A RESPERATOR. Dust masks are ineffective.
    On occasion the timber may appear to be a mustard yellow on the inside of the stock but will revert to the dark brown almost black color with age.

    As far as making furniture, it is hugely rewarding.

    Keep the weight in mind when designing, specially chairs, the weight will surprise an ill prepared gentleman hoping to briskly pull out a chair for his lady(he’ll end up at the cyro-practor).

    It is very unkind to dull cutters and an un-trained hand.
    When your tool technique is not up to scratch you will end up with chipped edges and break-out.
    When making joints and shaping by hand smaller actions deliver the best results.
    Reading the direction of the grain can be misleading. Work in a well-lit area of the shop.

    If your joints are super tight the timber is likely to crack, it is super-dense.
    When you dry fit your joints, be sure not to use too much force, rather shave material off and re-try.
    The timber has a tendency to hold fast if the joint has zero tolerance.
    If it does hold fast use very small movements to pry the joint apart.
    Always keep in mind that the timber is brittle but strong.

    Then we get to glue.
    In Africa we are not as fortunate as the developed world to have the range of choice like in Europe and the United-States.
    Cold glue as we know it is ineffective and releases at the slightest stress. Our Alcolin Ultra wood glue works well, but interior only.
    We use Balkotan mostly, very messy glue but effective. The equivalent would be something like ‘Gorilla’.

    Papering/sanding is time consuming. Best is to use a silicone based paper that deters build-up.
    If using a belt sander, be sure that the foot plate/pad is good and free of high spots. This timber is highly unforgiving and will highlight incorrect workmanship. It is just as highly rewarding when it is good.

    Finishing must be tested with the products that are available. Polywax products give good results, but if you are looking at varnishes know that some do not adhere in the long term. The varnish film separates when bumped or scratched due to the poor absorption of any liquid(solvent). Oiling could work, but that depends on the function of the piece.

  • Derrick Wardhaugh

    Sorry Eric, your post did not reflect before.

  • chris de beer

    Hi Derrick
    Thank you for this valuable information
    Regards
    Chris de Beer