Heavy Hardwoods - Red Balau

The Standard Malaysian Name for the heavy, red to red-brown timbers of the genus Shorea (Dipterocarpaceae). Vernacular names applied are too many to be listed here except for the more common ones, viz. balau laut merah (Peninsular Malaysia), balau merah (Peninsular Malaysia), damar laut merah (Peninsular Malaysia), membatu (Peninsular Malaysia), red selangan batu (Sabah and Sarawak), selangan batu merah (Sabah and Sarawak), semayur (Sarawak), seraya (Peninsular Malaysia) and seraya batu (Peninsular Malaysia). Major species include S.collina, S.guiso, S.inaequilateris, S.kunstleri and S.ochrophloia. The sapwood is pink, purple-brown or grey-brown and is fairly distinct from the heartwood, which is light to deep red-brown.

Also known as Selangan merah (Brunei); Balau merah and Gisok (Indonesia); Mai si khao (Laos); Guijo (Philippines); Chan, Lantan and Teng-tani (Thailand); and Chai (Vietnam).

DENSITY

The timber is a Heavy Hardwood with a density of 800-880 kg/m3 air dry.

NATURAL DURABILITY

The timber is moderately durable under exposed conditions (lasting from 2 to 5 years). The timber is subject to subterranean termite and fungal attacks.

PRESERVATIVE TREATMENT

Both S.guiso and S.ochrophloia have been found to be very difficult to treat with preservatives.

TEXTURE

Texture is moderately fine to slightly coarse and even, with deeply interlocked grain.

STRENGTH PROPERTIES

The timber falls into Strength Group A (Engku, 1988b) or SG 3 (MS 544:Part 2:2001).

Strength Properties of Red Balau

Species	Moisture Content (%)	Modulus of Elasticity(MPa)	Modulus of Rupture (MPa)	Compression parallel to grain (MPa)	Compression perpendicular to grain (MPa)	Shear strength(MPa)
S.Glauca	Green	13,700	94	43.6	5.52	10.1
S.Glauca	Air dry	14,800	100	55.2	5.52	12.0
S.kunstleri	Green	19,000	105	57.9	7.03	9.3
S.kunstleri	-	-	-	-	-	-
S.ochrophloia	Green	15,900	85	43.7	-	10.1
S.ochrophloia	Air dry	17,000	99	55.3	-	9.9

MACHINING PROPERTIES

It is easy to difficult to saw and work, although planing is easy and the surface produced is smooth to slightly rough.

Machining Properties of Red Balau

Species	Test Condition	Sawing		Planning		Boring		Turning
		Re Sawing	Cross Cutting	Moderately Easy	Smooth	Easy	Smooth	Ease of Turning	Quality of Finish
S.Guiso	Green	Easy	Easy	Easy	Smooth	Easy	Smooth	-	-
S.Guiso	Air dry	Slightly difficult	Slightly difficult	Easy	Slightly rough	Easy	Smooth	-	-
S.Laevis	Slightly difficult	Moderately Easy	Easy	Easy	Smooth	Easy	Smooth	-	-
S.Laevis	Air dry	Difficult	Slightly difficult	Easy	Smooth	Slightly difficult	Smooth	Easy	Smooth
S.Ochrophloia	Green	Slightly	Easy	Easy	Slightly	Easy	Slightly	-	-

Nailing Property

Nailing property varies according to species; S.guiso is reported to be excellent, while S.ochrophloia is good and S.kunstleri is poor..

Air drying

The seasonig properties of some of the species tested are summarised below:

Species	Time of air dry (Months)		Relative Humidity (%)(approx.)
Species		13mm Thick Boards	Relative Humidity (%)(approx.)	38mm Thick Boards
S.Guiso	4	6	Fairly slow drying; Moderate End-Checking;Slight Cupping,Splitting,Surface-Checking,Insect Attacks and Staining.
S. Kunstleri	4	6	Fairly slow drying; Moderate End-Checking;Slight Splitting,Surface-Checking.
S.Ochophloia	3	5	Fairly slow drying; Moderate End-Checking;Slight Splitting,Surface-Checking.

Kiln-Drying

Kiln Schedule G is recommended.

Kiln Schedule G

Moisture Content(%)	Temperature (Dry Bulb)		Temperature (Wet Bulb)		Relative Humidity (%)(approx.)
Moisture Content(%)					Relative Humidity (%)(approx.)
Green	120	48.5	115	45.0	85
60	120	48.5	113	45.0	80
30	140	60.0	131	55.0	80
25	160	71.0	146	63.5	70
20	170	76.5	147	64.0	55
10	180	82.0	114	62.5	40

SHRINKAGE

The shrinkage of red balau is summarised below:

Species	Shrinkage (%) (Green to Air Dry )		Remarks
Species		Radial	Remarks	Tangential
S.Guiso	1.6	3.6	High shrinkage
S.Kunstleri	2.2	3.3	High shrinkage
S.Ochophloia	1.4	3.2	High shrinkage

The logs are generally free from defects.

Uses

The timber is suitable for heavy construction under cover, beams, posts, joists, rafters, pallets (heavy duty), columns (heavy duty), tool handles (impact), joinery, cabinet making, fender supports, vehicle bodies (framework and floor boards), ship and boat building (keels, keelsons and framework), plywood, heavy duty furniture, flooring (heavy traffic), door and window frames and sills, staircase (carriage, angle block, rough bracket, riser, tread, bullnose, round end, winder, stringer and newel), cooling tower (structural members), railway sleepers (treated) as well as telegraphic and power transmission posts and cross arms (treated).

REFERENCES

Engku Abdul Rahman Chik. 1988b. Basic And Grade Stresses For Some Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 38. The Malaysian Timber Industry Board And Forest Research Institute Malaysia, Kuala Lumpur. 13 pp.

Lopez, D. T. 1981. Malaysian Timbers � Red Balau. Malaysian Forest Service Trade Leaflet No.45. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur.7 pp

Menon,P.K.B. 1986. Uses of Some Malaysian Timbers. Revised by Lim, S.C. Timber Trade Leaflet No.31. The Malaysian Timber Industry Board and Forest Research Insitute Malaysia,Kuala Lumpur.48 pp.

MS 544:Part 2:2001:Code Of Practice For Structural Use Of Timber.Permissible Stress Design of Solid Timber.

Wong, T.M.1982.A Dictionary of Malaysian Timbers. Revised by Lim, S.C.&Chung, R.C.K. Malayan Forest Record No.30. Forest Research Institute Malaysia Kuala Lumpur.201 pp

Heavy Hardwoods - Balau Red