[Oriental Timber]

Understanding Poplar Plywood

1. Face/Back: Okoume Veneer

Grade

	Face AA (BSI-B)	Face A (BSI-BB)	Face B (between BSI BB and CC)	Face C (JPIC-CC)	Back
Pin Knot,	Not Clustered	Not Clustered	Allowed
Sound Live Knot	10mm max. diam. & ≤ 5 units	20mm max. diam. & ≤ 10 units	Allowed
Intergrown Knot	Not Allowed	10mm max. diam. & ≤ 6 units	25mm max. diam. & ≤ 8 units	≤ 12 units	Allowed
Dead Knot	Not Allowed	4mm max. diam. & ≤ 6 units	6mm max. diam. & ≤ 8 units	15mm max. diam. & ≤ 12 units	50mm max. diam.
Bark & Resin pocket	Not Allowed	15mm max. length & ≤ 6 units	30mm max. length & ≤ 8 units	Allowed
Knot Holes, Worm Holes, Dog Holes	Not Allowed	2mm max. diam. & ≤ 4 units	4mm max. diam. & ≤ 4 units	Allowed
Worm Tracks & Vine Mark	Not Allowed	15mm max. length & ≤ 6 units	30mm max. length & ≤ 8 units	Allowed
Split	Not Allowed	1mm max width, 200mm max. length	1.5mm max width, 300mm max. length	3mm max width, 400mm max. length	6mm max width
Rot & Decay	Not Allowed			Incipient, no flaked, ≤ 1%	Incipient, no flaked
Natural Discoloration	Not Allowed	≤ 5%	≤ 25%	Allowed
Blue Stain & Oil Stain & Fleck Streaks	Not Allowed		Slightly	Allowed
Rough Cut & Ruptured Grain	Not Allowed	≤ 4%	≤ 10%	Allowed
Joint	Not Allowed			3 joint max	Allowed
Patch & Shim	Not Allowed		≤ 0.5% & ≤ 3 units	≤ 3%	Allowed

2. Core: Poplar Veneer

a. Grade:

Grade

Description

Almost have few defects, some sound live knots. Usually used as the top & the bottom layer of the core

Have some dead rot or flaked knots, some patches & shims, used as the middle layer of the core

Have many dead rot or flaked knots, many patches & shims, some flaked pieces, used as the middle layer of the core

Fragmentary Pieces, big regular pieces joint together, used as the middle long grain layer of the core

Fragmentary Pieces,

Irregular small pieces mixed together,

used as the middle long grain layer of the core

Note: B Grade subdivide to 3 sub-grade:

B grade: with one or two patches or limited knots but well repaired.

B+ grade: patches or knots smaller or less than B grade but well repaired.

B- grade: patches or knots bigger or more than B grade but well repaired.

3. Veneer moisture content :

There are three ways of veneer moisture content treatment in China:

Treatment

Machinery dryer

( precise control )

Simple Kiln dryer

( at least )

air dryer

( can not promise even moisture content )

4. Face/Back repair :

There are two ways to repair Face/Back in China:

Repair

Putty repair

wood silk repair

5. Smoothness treatment :

There are three ways of smoothness treatment in China:

triple sanding ( the best )

double sanding ( standard )

only one sanding ( lower grade )

1st step : heavy calibrating core veneer before laminating 2 nd core layer

2nd step : strong sanding on 2 nd core layer

3rd step : light sanding on face/back

1st step : heavy calibrating core veneer

2nd step : light sanding on face/back

on face/back