Kwila

Overview

Kwila is a high quality, strong and durable hardwood. It has become popular in New Zealand and Australia, where it is in high demand for decking, outdoor furniture and high quality interior finishing’s.

Kwila is suitable for superior joinery including staircase materials, handrails and posts. It produces high quality, hard wearing flooring and is also used for furniture (indoors and outdoors) and decking. Also a popular timber for boat and ship building.

Botanical Name: Intsia
Standard Trade Names: Kwila.
Merbau.
Other Names: Bendora (PNG) merbau (Malaysia) u’ula (Solomon Is.) go nuoe (Vietnam) Borneo teak, moluccan ironwood (U.K.) lum-pho, mokhamong (Thailand) vesi (Fiji) ipil (Philippines).
Origin of Product: Papua New Guinea.
Grade: Select & Better.
Availability: Available ex-stock in kiln dried sizes from 50 to 200mm wide and 25, 32, 40, 50, 75 and 100mm thicknesses.
Species information for this product:
  • The timber is either a yellowish-brown or dark brown in colour, darkening on exposure to light. In exterior situations it weathers slowly to a silvery-grey colour.
  • Kwila is not very durable in the ground, as the extractives, which contribute toward its durability, are prone to leaching. This leaching process leads to the timber ‘bleeding’ and imparting a dark brown stain which marks the contact surface. A sealant should be applied to the timber if it is to be in “contact” situations e.g window sills, when exposed to the weather.
  • The timber seasons very well with little degrade. Preliminary air-drying to 25% moisture content is preferable before kiln drying. Board ends need to be heavily sealed to avoid end splitting and surface checking during drying. After seasoning, it is a very stable timber with low hygroscopic movement.
Names
Family: Caesalpiniaceae.
Species: Intsia.
I. bijuga (Colebr.) Kuntze.
I. palembanica Miq.

Properties

Properties
Density: 670-800 Kg/m3 @ 12% m.c.
Durability: Class 1: Very Durable.
Colour: Golden-brown, yellow-brown, red-brown to blood red.
Texture: Moderately coarse but even.
Grain: May be straight or slightly interlocked, sometimes wavy.
Figure: Ribbon figure evident on quarter-sawn faces when interlocked grain present. Cathedral like figure on back sawn faces.
Permeability: Class 4: Highly resistant; heartwood is untreatable and sapwood is comparatively narrow.
Workability
General: Very good working and finishing properties.
Sawing: Saws well but saw blades may ‘gum-up’ after prolonged sawing.
Planing: Excellent, some care required where grain irregularities occur.
Blunting: Moderate to severe
Boring: Additional power may be required, some burning may occur. Clean exit hole.
Turning: Denser material will not turn as well, and will tend to has a more fibrous finish.
Nailing: Pre-boring is recommended.
Gluing: Gluing can be difficult due to the natural oiliness of the timber.
Finishing: Excellent, will sand to a very fine finish and produce a high polish with golden lustre.

Mechanical

Mechanical Properties
Strength: SD3.
Structural Grade: F27 (select grade).
Hardness (Janka): 8.6kN (seasoned), 7.6kN (unseasoned).
Max. Crushing Strength: 81MPa (seasoned), 55Mpa (unseasoned).
Modulus of Elasticity: 18GPa (seasoned), 14GPa (unseasoned).
Modulus of Rupture: 147MPa (seasoned), 103MPa (unseasoned).
Seasoning
General: Seasons well with little degrade.
Movement: Very low.
Shrinkage: Very low.