Sepetir

Sepetir Wood: Versatile and Durable for Multiple Applications

Introduction
Sepetir is the Standard Malaysian Name for the timber derived from Copaifera palustris and Sindora spp. (Leguminosae family). Recognized by various names across Malaysia and Southeast Asia, Sepetir is a light hardwood known for its moderate strength and durability. Its distinctive appearance, featuring a pinkish-brown sapwood and a streaked brown heartwood, makes it highly prized for both functional and decorative uses.

Key Characteristics

• Density: A light hardwood with a density ranging between 530-785 kg/m³ when air-dried, Sepetir is versatile for a range of indoor and outdoor applications.

• Durability: Classified as not durable to moderately durable, Sepetir is susceptible to termites and fungi but can be enhanced with preservative treatment.

• Strength: Sepetir falls under Strength Group C, making it moderately strong and suitable for light construction.

• Machining: It is easy to work with, especially in planing and finishing, although resawing and cross-cutting may present some challenges.

Applications

Sepetir wood is widely used in both structural and decorative projects:

• General Construction: Suitable for light construction, including posts, beams, joists, and rafters.

• Furniture: Its smooth finish and moderate strength make it ideal for crafting furniture.

• Interior Finishing: Commonly used for door and window frames, sills, and decorative panelling.

• Pallets & Crates: Often used for making light-duty pallets and packing crates.

• Ornamental Items: The streaked variety of Sepetir is highly valued for cabinets, mouldings, and ornamental designs.

Drying & Shrinkage

• Air Drying: Sepetir dries moderately slowly, with minimal degrade. It takes about 3-5 months to air dry, depending on board thickness.

• Kiln-Drying: For optimal results, Kiln Schedule G or Schedule D (for streaked wood) is recommended to prevent warping.

• Shrinkage: With radial shrinkage averaging 1.5% and tangential shrinkage at 2.9%, Sepetir maintains good dimensional stability.

Conclusion
Sepetir wood's versatility, strength, and attractive grain pattern make it an excellent choice for both functional construction and decorative work. Its adaptability across various applications, from furniture to general construction, ensures its continued popularity in wood markets.

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)

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)

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 

Kiln Schedule G

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.