PNG Oak - Pterygota
PNG Oak is a good economical replacement for American White Oak. The color is paler than American White Oak but does have a very similar grain.
- The sapwood varies from straw to pale yellow, and is not distinct from the heartwood which is cream to pale brown with ripple marks appearing.
- The grain is generally straight but can be shallowly interlocked producing some beautifully figured wood with a moderately medium to coarse texture. Also the attractive figure on tangential face and large ray fleck on the radial face are prominent features.
- Logs are reported to be vulnerable to blue-stain, termite, and pinhole borer attack if they are not promptly removed from the forest after felling. Seasoning is very slow, however the wood can be kiln-dried from the green condition, but there may be some degrade in the form of end-splitting.
- Turning and moulding operations are easy and give an excellent finish. Sawing and planning can be difficult with low speed machinery. Penetration and retention of preservatives in both sapwood and heartwood are reported to be adequate.
- PNG Oak is used in interior finishing, cabinet work, joinery, mouldings, furniture, flooring, paneling, veneer, tool handles, cladding, handrails, plywood, general construction and bridge building.
Names
Family:
Sterculiaceae
Species:
Pterygota
P. horsfieldii (R.Br.) Kosterm.
syn. P. forbesii F. Muell.
P. horsfieldii (R.Br.) Kosterm.
syn. P. forbesii F. Muell.
Standard Trade Names:
White Tulip Oak
Other Names:
White Tulip Oak (PNG)
PROPERTIES
Density:
640-750 Kg/m3 @ 12% m.c
Colour:
Cream to very pale brown.
Texture:
Coarse to moderately course.
Grain:
Usually straight.
Figure:
Fine, decorative grain figure on quarter cut material.
Durability:
Class 3: Moderately Durable
Permeability:
Class 2: Sapwood is permeable and heartwood is reasonably uniform to pressure impregnation
WORKABILITY
General:
Good overall, knives need to be sharp.
Sawing:
Difficult with low speed machinery, there may be some tearing in quarter-sawing stock containing interlocked grain.
Planing:
Works fairly easily but material with interlocked grain may tear.
Blunting:
Low
Boring:
Readily bored.
Turning:
Easy
Nailing:
Must pre-bore.
Gluing:
Accepts all adhesives satisfactorily.
Finishing:
Takes stain and polish very well.
MECHANICAL PROPERTIES
Strength:
SD4
Structural Grade:
F14 (select grade, seasoned).
Hardness(Janka):
6.0kN (seasoned), 4.0kN (unseasoned).
Max. Crushing Strength:
64MPa (seasoned), 38Mpa (unseasoned).
Modulus of Elasticity:
15GPa (seasoned), 13GPa (unseasoned).
Modulus of Rupture:
106MPa (seasoned), 67MPa (unseasoned).
SEASONING
General:
Seasons very slowly
Movement:
Very low
Shrinkage:
Medium
