Merbau
Botanical name
Intsia bijuga
Intsia palembanica
Origin
Merbau grows in South-east Asia, the Philippines, Solomon Islands, Fiji and Papua New Guinea.
Trading names
Kwila
Merbau
Ipil
Vesi
Appearance
Heartwoodmay be bright yellow when first cut but becomes pale to dark reddish brown.
Sapwoodpale yellow and usually distinct from the heartwood.
Texturemoderately coarse but even.
Grainsometimes slightly interlocked, producing a ribbon figure on the radial surface.
Odourcharacteristic oily odour when freshly cut.
Rather greasy to the touch.
General comment
Dries slowly with little degrade.

It cuts cleanly but saw teeth tend to become clogged with a gummy material.

Predrilling may be needed when nailing.

Glues reasonably satisfactorily except with casein.

Sanding dust can be irritating to both skin and mucous membranes. Turns well.

Turns well.

The vessels contain a yellow substance that will stain textiles and concrete.
Common uses
Furniture, flooring, decking, panelling, turnery, sills, boat building, cross-arms, carving, vats, window joinery, veneer.
Properties
(See notes below)
Hardness rating
Average Hardness Rating - Dry: Hard

Lyctid Susceptibility of Sapwood
Susceptible
(source AS 5604)

Termite Resistance of Heartwood (inside above ground)
Resistant
(source AS 5604)

Marine Borer Resistance of Heartwood
Class 3
(source AS 5604)

Natural Durability Rating of Heartwood Above Ground
Class 1
(source AS 5604)

Natural Durability Rating of Heartwood In-Ground Contact
Class 3
(source AS 5604)


Notes
Density: 'Green Density' (GD) is the density of the wood at the time the living tree is felled. It varies considerably with the season, weather conditions, the age of the tree and so on; the quoted figure must therefore be accepted as a guideline only and when accurate green density figures are required for, say, assessment of transport costs, it is advisable to carry out accurate determinations on the materials involved.

'Dry Density' or 'Air Dry Density' (ADD) is the average density of the wood at 12 per cent moisture content. It too varies with conditions of growth, climate and maturity of wood.

There are published figures for both Green Density and Air Dry Density of most commercial species.

The figures given above have been rounded to the nearest 50.

Hardness rating: the hardness rating of a timber species is measured by the Janka Test. This is a standard test which measures the penetration into the timber of a common load and projectile. The results relate to a hardness capacity of the material and are expressed in kN. This information is useful where the timber may be subject to potential damage from impacts e.g. a dance floor. There are 2 sets of published figures; one for 'Green' or freshly felled timber and one for seasoned timber - i.e. timber with a moisture content of 12%.

The ratings given here are:
  Soft - less than 5.5
  Moderate - 5.5 to 7.0
  Hard - 7.1 to 10.0
  Very Hard - greater than 10.0.

Lyctid susceptible sapwood: Only the sapwood of some hardwoods is susceptible to lyctid borer attack. No softwoods are susceptible to attack.

Natural durability ratings: The natural durability rating of a timber species is a rating of the timber's resistance to attack by wood destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The rating is based on the testing of stakes and poles embedded in the ground and on expert opinion of historical performance. There are 2 sets of ratings: one for above ground use and one for in-ground contact use. The lower the number the higher the performance in terms of durability. This information is useful for specifying material for external or exposed applications.
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