Kasai


INTRODUCTION

The Standard Malaysian Name for the timber of Pometia spp. (Sapindaceae). Vernacular names applied include kasai (Peninsular Malaysia, Sabah and Sarawak) with various epithets, datanut (Sabah), enselan (Sarawak), rapanah (Sarawak), sibu (Sarawak) and silak (Sarawak). Major species include P. pinnata (including f. alnifolia) and P. ridleyi. The sapwood is lighter in colour than the heartwood and is not sharply defined from the heartwood, which is pink, red or red-brown.

Also known as Taun (Australia); Ndawa (Fiji); Djampanga, Galunggung, Ihi mendek, Kasai, Kaseh, Kasie, Kempil kujat, Landoeng, Leungsir, Matoa, Pangah, Singkuang and Tawan (Indonesia); Chieng dong, Haman and Kwaang (Laos); Paga-nyet-su ava (Myanmar); Matoa and Taun (Papua New Guinea); Malugai, Malugai-liitan and Tagaui (Philippines); Tava (Samoa Islands); Taun (Soloman Islands); Daengnam and Sai (Thailand); and Truong (Vietnam).


DENSITY

The timber is a Medium Hardwood with a density of 735-915 kg/m3 air dry.


NATURAL DURABILITY

From the graveyard tests of P. pinnata f. glabra, all the 40 test sticks tested were found to be sound during the first two years of service. Around 10 and 12 per cent of the test sticks were destroyed during the third and fourth year of service respectively. The test sticks seem to deteriorate fairly quickly on the fifth year in service and only 15 per cent of the test sticks remained sound. All the test sticks were completely destroyed on the seventh year. Based on the results obtained above, kasai has been classified as a moderately durable timber with an average service life of 5 years under natural conditions (Jackson, 1965). An earlier series of durability test carried out on kasai at the Forest Research Institute Malaysia (FRIM) indicated that several test sticks perished fairly quickly while others persisted in a partially damaged state for 10 years or more. Kasai is also not resistant to marine borer attacks. A test stick of 125 mm x 250 mm x 1,925 mm which was tested in Port Klang was destroyed in less than two years. Similar sized test sticks treated with a mixture of 50 per cent creosote and 50 per cent diesel oil using the full cell process (with the absorption of 110 kg/m3 (6.9 lb/ft3) remained serviceable for only 2 years (Desch, 1954).


PRESERVATIVE TREATMENT

The timber is very difficult to treat with preservatives.   


TEXTURE

Texture is moderately coarse but even, with straight or shallowly interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group C (Burgess, 1958) or SG 4 (MS 544:Part 2:2001).


Strength Properties of Kasai

Species

Test Condition

Modulus of Elasticity (MPa)

Modulus of Rupture (MPa)

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

Shear strength (MPa)

P. pinnata f. glabra

Green

-

-

37

4

9

Air dry

-

-

49

5

13

P. ridleyi

Green

15,700

81

41

7

13

Air dry

17,000

106

54

10

14


MACHINING PROPERTIES

It is easy to work when green but is slightly difficult to work when dried. Planing is easy in either condition and the finish of green boards is smooth while the finish of dried boards is rough.


Machining Properties of Kasai

Test Condition

Sawing

Planing

Boring

Turning

Re-sawing

Cross Cutting

Ease of planing

Quality of finish

Ease of boring

Quality of finish

Ease of turning

Quality of finish

Green

easy

easy

easy

smooth

moderately easy

moderately smooth

-

-

Air dry

slightly difficult

slightly difficult

easy

rough

slightly difficult

slightly rough

slightly difficult

rough


NAILING PROPERTY

Nailing property is rated as good.


AIR DRYING

The timber seasons fairly slowly but with very minor degrade. Slight cupping, bowing and end-checking are the main sources of degrade. 13 mm thick boards take approximately 3 months to air dry, while 38 mm thick boards take 5 months.


KILN-DRYING

Kiln Schedule D is recommended.


Kiln Schedule D

Moisture Content (%)

Temperature (Dry Bulb)

Temperature (Wet Bulb)

Relative Humidity (%) (approx.)

F

C

F

C

Green

105

40.5

101

38.0

85

60

105

40.5

99

37.0

80

40

105

40.5

96

35.5

70

35

110

43.5

97

36.0

60

30

115

46.0

97

36.0

50

25

125

51.5

101

38.0

40

20

140

60.0

105

40.5

30

15

150

65.5

112

44.5

30


SHRINKAGE

Shrinkage is rather high. Radial shrinkage averages 2.8% while tangential shrinkage averages 3.5%.


MOVEMENT IN SERVICE

The movement of seasoned timber is classified under Type III.


DEFECTS

The timber is generally free from any major defects. Slight defects such as 'pin' and 'shot' holes have been found in some logs tested. Powder-post beetle attacks may occur during seasoning. A few boards of P. ridleyi tested have also been found to be attacked by longhorn beetles (holes of about 12 mm diameter). End-checking, splitting, compression failure and brittle heart of up to 100 mm diameter have been recorded from logs examined.


USES

The timber is suitable for furniture manufacture, tool handles, beams, posts, joists, rafters, door and window frames and sills, railway sleepers, joinery, cabinet making, vehicle bodies (planking), ship and boat building (keels, keelsons and framework), plywood, flooring (heavy traffic), columns (light duty), panelling, partitioning, staircase (angle block, rough bracket, newel, apron lining and sprandrel framing) and interior finishing like mouldings and skirtings.


REFERENCES

  1. Burgess, H. J. 1958. Strength Grouping of Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 25. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 15 pp.
  2. Desch, H. E. 1954. Manual of Malayan Timbers. Vol. II. Mal. For. Rec. No. 15.
  3. Jackson, W. F. 1965. Durability of Malayan Timbers. Mal. For. Ser. Trade Leaflet No. 38.
  4. Lim, S. C. 1984. Malaysian Timbers - Kasai. Timber Trade Leaflet No. 92. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 8 pp. 
  5. 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 Institute Malaysia, Kuala Lumpur. 48 pp.
  6. MS 544:Part 2:2001. Code of Practice for the Structural Use of Timber: Permissible Stress Design of Solid Timber.
  7. Wong, T. M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S. C. & Chung, R. C. K. Malayan Forest Records No. 30. Forest Research Institute Malaysia, Kuala Lumpur. 201 pp.