Red Balau


INTRODUCTION

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. guiso

Green

13700

94

43.6

5.52

10.1

Air dry

14,800

100

55.2

5.52

12.0

S. kunstleri

Green

19,000

105

57.9

7.03

9.3

Air dry

-

-

-

-

-

S. ochrophloia

Green

15,900

85

43.7

-

10.1

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

Planing

Boring

Turning

Rip-sawing

Cross Cutting

Ease of planing

Quality of finish

Ease of boring

Quality of finish

Ease of turning

Quality of finish

S. guiso

Green

easy

easy

easy

smooth

easy

smooth

-

-

Air dry

slightly difficult

slightly difficult

easy

slightly rough

easy

smooth

moderately easy

moderately smooth

S. kunstleri

Green

easy to difficult

slightly difficult

easy

smooth

easy

smooth

-

-

Air dry

difficult

slightly difficult

easy

smooth

slightly difficult

smooth

easy

smooth

S. ochrophloia

Green

slightly difficult

easy

easy

slightly rough

easy

slightly rough

-

-

Air dry

slightly difficult

easy

easy

slightly rough

moderately easy

slightly rough

difficult

smooth to rough


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 to air dry (months)

Remarks

13 mm
thick boards

38 mm
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 and surface-checking.

S. ochrophloia

3

5

Fairly slow drying; moderate end-checking; slight splitting and surface-checking.


KILN-DRYING

Kiln Schedule G is recommended. 


Kiln Schedule G

Moisture Content (%)

Temperature (Dry Bulb)

Temperature (Wet Bulb)

Relative Humidity (%) (approx.)

F

C

F

C

Green

120

48.5

115

45.0

85

60

120

48.5

113

45.0

80

40

130

54.5

123

50.5

80

30

140

60.0

131

55.0

75

25

160

71.0

146

63.5

70

20

170

76.5

147

64.0

55

10

180

82.0

144

62.5

40


SHRINKAGE

The shrinkage of red balau is summarised below:

Species

Shrinkage (%) 
(Green to air dry)

Remarks

Radial

Tangential

S. guiso

1.6

3.6

High shrinkage

S. kunstleri

2.2

3.3

High shrinkage

S. ochrophloia

1.4

3.2

High shrinkage

 

 

 

 

 

DEFECTS

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

  1. 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.
  2. 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
  3. 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.
  4. MS 544: Part 2: 2001: Code Of Practice For Structural Use Of Timber. Permissible Stress Design of Solid Timber.
  5. 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.