Sepetir


INTRODUCTION

The Standard Malaysian Name for the timber of Copaifera palustris and Sindora spp. (Leguminosae). Vernacular names applied include sepetir (Peninsular Malaysia, Sabah and Sarawak) with various epithets, petir (Sarawak), tampar hantu (Sarawak) and tepih (Sarawak). Major species include Copaifera palustris; Sindora coriacea, S. echinocalyx, S. siamensis, S. velutina and S. wallichii. The sapwood is light grey-brown or beige with a pink tinge and is clearly defined from the heartwood, which is brown with a pink tinge and darkens on exposure. A corewood, which is streaked with layers of darker coloured to almost black wood is often developed.

Also known as Sepetir (Brunei); Krakas, Krakas meng and Krakas sbek (Cambodia); Ensunut, Kaju galedupa, Samparantu, Sampit, Sansanit, Saserut, Sasundur, Sepatir, Seperhantu, Sepetir, Sepetir berduri, Sinampar, Sindur and Tamparan hantu (Indonesia); Mai tao ho (Laos); Kayu galu and Supa (Philippines); Khaman, Kling, Ma Ka Tae and Makata (Thailand); and Gomat (Vietnam).


DENSITY

The timber is a Light Hardwood with a density of 530-785 kg/m3 air dry.


NATURAL DURABILITY

Two series of graveyard tests were conducted at the Forest Research Institute Malaysia (FRIM) on S. coriacea. The first series was conducted in only one test ground and the specimens were found to last for only 1.6 years, while the other series was conducted in three different grounds. The results obtained showed a life span of 2.6 years. The timber is thus classified as not durable to moderately durable. The specimens were destroyed by both termites and fungi. The timber is highly susceptible to powder-post beetle attacks (Menon, 1957). Test sticks of S. coriacea treated by the open tank method with 100% creosote to an absorption of 141 kg/m3 (8.83 lb/ft3) were found to be durable. Only 83% of the 40 test sticks were destroyed after 18 years.


PRESERVATIVE TREATMENT

The timber is classified as moderately difficult to treat. Under standard open tank treatment using a mixture of creosote and diesel fuel on test sticks of 65 mm x 65 mm x 900 mm, an average absorption of 96 kg/m3 (5.97 lb/ft3) was obtained. Under the full-cell process and a 3% Copper-Chrome-Arsenic solution, the heartwood of sepetir was found to be difficult to treat as only absorption of 73 kg/m3 (4.58 lb/ft3) was recorded. The dry salt retention achieved was only 2.2 kg/m3 (0.14 lb/ft3).


TEXTURE

Texture is moderately fine and even, with straight or shallowly interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group C (Engku, 1988b) or SG5 (MS 544: Part 2:2001).


Strength Properties of Sepetir (S. coriacea)

Test Condition

Modulus of Elasticity (MPa)

Modulus of Rupture (MPa)

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

Shear Strength (MPa)

Green

11,700

71

36.4

4.28

10.1

Air dry

13,600

92

46.3

5.93

13.6


MACHINING PROPERTIES

It is slightly difficult to difficult to resaw and cross-cut but is easy to plane and the surface produced is smooth.


Machining Properties of Sepetir (S. coriacea)

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

slightly difficult

slightly difficult

easy

smooth

slightly difficult

smooth

-

-

Air dry

difficult

difficult

easy

smooth

slightly difficult

smooth

moderately easy

slightly rough


NAILING PROPERTY

The nailing property is rated as good.


AIR DRYING

The timber dries moderately slowly, with almost no degrade, although the sapwood is likely to be attacked by powder-post beetles. 13 mm thick boards take approximately 3 months to air dry, while 38 mm thick boards take 5 months.


KILN-DRYING

For kiln-drying, Schedule G is recommended. The timber dries fast but has a marked tendency to warp if the boards contain dark streaks. For such material, 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


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

Shrinkage is rather high, with radial shrinkage averaging 1.5% and tangential shrinkage averaging 2.9%.


DEFECTS

Sepetir logs are normally free from serious defects. However, defects such as spongy heart and pin holes have been recorded (Desch, 1957). The sapwood of the logs has been reported to be rapidly attacked by dry-wood termites (Thomas, 1970).


USES

The timber is suitable for general planking, light construction, posts, beams, joists, rafters, ceiling, packing boxes and crates, pallets (expendable and permanent light duty types), door and window frames and sills (internal use only), tool handles (non impact), railway sleepers, cooling tower (non structural members), staircase (apron lining, baluster, handrail, newel and sprandrel framing), flooring, furniture, plywood, picture frames and ornamental items. The streaked material is, however, highly prized as a superior cabinet wood and is suitable for decorative works, joinery, panelling and mouldings.


REFERENCES

  1. Desch, H. E. 1957. Manual of Malayan Timbers. Vol.1. Malayan Forest Record No.15.
  2. 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.
  3. Ho, K. S. 1982. Malaysian Timbers - Sepetir. Malaysian Forest Service Trade Leaflet No. 60. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 9 pp.
  4. Menon, K. D. 1957. Susceptibility of Commercial Species of Malayan Timbers to Powder-post Beetle Attack. Mal. For. Vol. 20 (1) pp. 19-23.
  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 Insitute Malaysia, Kuala Lumpur. 48 pp.
  6. MS 544: Part 2: 2001: Code Of Practice For Structural Use Of Timber. PermissibleStress Design of Solid Timber.
  7. Thomas, A. V. 1970. Malayan Timbers Sepetir, Merawan. Malaysian Forest Service Trade Leaflet No.16. (Reprinted).
  8. 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.