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 | 75 |
| 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
- Desch, H. E. 1957. Manual of Malayan Timbers. Vol.1. Malayan Forest Record No.15.
- 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.
- 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.
- Menon, K. D. 1957. Susceptibility of Commercial Species of Malayan Timbers to Powder-post Beetle Attack. Mal. For. Vol. 20 (1) pp. 19-23.
- 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. PermissibleStress Design of Solid Timber.
- Thomas, A. V. 1970. Malayan Timbers Sepetir, Merawan. Malaysian Forest Service Trade Leaflet No.16. (Reprinted).
- 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.