Merbau

Botanical Name: Intsia Bijuga
Also known as Kwila, Ipil, Vesi, Johnstone River Teak or Scrub Mahogany

Merbau is a popular hardwood derived largely from areas in South East Asia, Papua New Guinea, the Pacific islands, and northern Queensland. With its high degree of natural durability and strength it is used externally in engineering, construction and marine applications.

The wood grain is variable but usually interlocked or wavy, which produces a ribbon figure on the radial surface. The timber has a coarse but even texture. It has a characteristic oily odour when cut.

Once cut, the heartwood will initially appear as yellowish-brown or orange-brown before deepening to a pale to dark reddish brown.

This contrasts with the merbau sapwood, which appears white, pale yellow or buff.

Merbau is a versatile wood product. It is utilised for larger-scale projects and general construction, along with common use for outdoor settings and barbeque trolleys, and for joinery, flooring and fitting purposes. As it turns well and responds to hand tools it can be applied to more specialised work, such as cabinet making, musical instruments, boat building, carving and tool handles.

Density 830 kg/m3
Strength Groups S2 unseasoned; SD3 seasoned
Stress Grades F11, F14, F17, F22, (unseasoned), F14, F17, F22, F27, (seasoned)
Joint Groups J3 unseasoned; JD2 seasoned
Shrinkage to 12% MC 2.6% (tangential); 1.2% (radial)
Unit Shrinkage 0.30% (tangential); 0.19% (radial)
Durability Above-ground Class 1 – life expectancy over 40 years
Durability In-ground Not suitable for in-ground use
Lyctine Suceptibility Untreated sapwood susceptible to lyctid borer attack
Termite Resistance Resistant
Preservation Sapwood accepts preservative impregnation
Seasoning Merbau seasons well
Hardness Hard (rated 2 on a 6 class scale)
Machining Working properties variable
Fixing Merbau tends to split unless pre-bored
Gluing Glues satisfactorily except with casein glues
Finishing It takes paint, stain and polish well, but gum bleed-through or oily patches may affect the finish
Fire Rating Bal 29 Rating in Bush Fire Prone Areas