White Birch PLYWOOD GRADE DESCRIPTIONS

White Birch PLYWOOD GRADE DESCRIPTIONS

Original Please check https://www.probex.ee/grades-eng.html ,Thanks for PROBEX

Birch Plywood is subdivided by the following grades depending on face veneer quality:

Е (Elite)
B(I)
S
ВВ ( II )
СР ( III )
WG
С ( IV )

Plywood grade is marked by face and back veneer quality (face/back). For example:
Е/В ( E/I ), В/В ( I/I ), I/II, II/II, II/III, II/IV, III/III, III/IV, IV/IV etc.

Grade “E” (Elite): Perfect grade
Categories of defects Permissible amount of defects
Pin knots Permitted
Irregularities in the structure of wood Permitted, but slight
Coloured streaks Permitted accosionally

 

Categories of defects Permissible amount of defects
Pin knots Permitted up to 3 per 1 m²
Other knots and patched holes:

sound knots

unsound (falling) knots

Permitted up to an individual maximum diameter of 15 mm in amount of 5 per 1 m²

Permitted up to an individual maximum diameter of 6 mm in amount of 3 per 1 m²

Knots and knotholes repairement Not Permitted
Irregularities in the structure of wood Permitted
Hearth and discoloration Not more than 5% of surface
Closed splits and checks, patched Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet
Open splits Not Permitted
Discolouration and coloured streaks Permitted, but slight
Defects at the edges due to sanding or sawing Allowed up to 2 mm from the edge
Glue penetration Not Permitted
Sanding through Not Permitted

Grade “B” ( I ): Almost without deffects intended for natural finish. For furniture construction and decoration.
Grade “S”: Almost without defects, Occasional small sound tight knots are allowed and up to 2 patches are allowed per m2. Used for varnishing and painting in furniture construction, decoration and lamination of various kind of wood.
Categories of defects Permissible amount of defects
Pin knots Permitted (diameter to 3mm)
Sound intergrown knots light/dark “Allowed up to an individual maximum diameter of 20 mm with total quantity not more than 2,5 per m2 (or total diameter up to 50mm/m2 of the panel square) 0,5”
Partly intergrown, open knots, knotholes, worm tracks Allowed up to an individual maximum diameter of 10 mm with total quantity not more than 2,5 per m2 (or total diameter up to 25mm/m2 of the panel square) 0,5
Knots and knotholes repairement Not Permitted
Irregularities in the structure of wood Permitted
Hearth and discoloration Not more than 5% of surface
Closed splits and checks, patched Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet
Irregularities in the structure of the wood Allowed cross grain, curly grain and burls
Hearth and discoloration Not more than 20% of surface
Defects at the edges due to sanding or sawing Allowed up to 5 mm from the edge
Glue penetration Allowed not more than, 1% of the panel surface
Sanding through Not Permitted
Grade “BB” ( II ): For furniture construction and for covering with decorative materials.
Categories of defects Permissible amount of defects
Pin knots Permitted
Sound knots Permitted up to an individual maximum diameter of 25 mm in amount of 10 per 1 m²
Other knots and patched holes:

unsound (falling) knots

Permitted up to an individual maximum diameter of 6 mm in amount of 6 per 1 m²
Irregularities in the structure of wood Permitted, but slight
Open splits and patched holes Permitted for an individual maximum length up to 200 mm and width up to 2 mm in amount of 2 per 1 m width of sheet
Closed splits and checks, patched Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet
Discolouration and coloured streaks Not more than 30% of surface
Repaired defects (inserts) Permitted up to 8 per m²
Double inserts Not Permitted
Sanding through Not allowed
Glue penetration Permitted up to 2% of surface
Defects on the edges due to sanding or sawing Admitted up to 5 mm from the edge
Grade “CP”: Suitable for construction, which are not observed and for special packaging. And also calibration allows to use this plywood for decorating with valuable veneer.
Categories of defects Permissible amount of defects
Pin knots Permitted
Sound knots Permitted along with cracks for width up to 1,5 mm
Other knots and patched holes Permitted up to an individual maximum diameter of 6 mm in amount of 10 per 1 m²
Repaired defects (inserts) Allowed
Double inserts Allowed
Irregularities in the structure of the wood Allowed
Discolouration and coloured streaks Permitted
Open splits Permitted for an individual maximum length up to 300 mm and width up to 5 mm in amount of 5 per 1 m length of sheet
Closed splits and checks Permitted
Hearth and discoloration Permitted
Open joints, patched Permitted for an individual maximum width up to 2 mm and length of 200 mm, no more than 1 per metre of sheet width
Overlaps Permitted for a maximum length of 200 mm and no more than 1 per metre of sheet width
Hollows, bumps and imprints Permitted, but slight
Roughness Permitted, but slight
Inserts Unlimited number permitted
Sanding through Permitted up to an extent of 10 cm²
Glue penetration Permitted up to an extent of 5% of the surface of sheet
Defects on the edges due to sanding or sawing Admitted up to 4 mm from the edge
Grade “WG”: Suitable for construction, which are not observed and for special packaging.
Grade “WG”: Suitable for construction, which are not observed and for special packaging.
Categories of defects Permissible amount of defects
Sound intergrown knots Allowed up to an individual maximum diameter of 65 mm
Other knots and knot holes Allowed up to an individual maximum diameter of 15 mm with total quantity not more than 10 per m2
Repaired defects (inserts) Allowed
Double inserts Allowed
Irregularities in the structure of the wood Allowed
Open splits Permitted for an individual maximum length up to 300 mm and width up to 4 mm in amount of 2 per 1 m length of sheet
Closed splits Permitted
Hearth and discoloration Permitted
Open joints, patched Permitted for an individual maximum width up to 2 mm and length of 200 mm, no more than 1 per metre of sheet width
Overlaps Permitted
Hollows, bumps and imprints Permitted, but slight
Inserts Unlimited number permitted
Sanding through Permitted up to 5% of surface
Glue penetration Permitted up to an extent of 5% of the surface of sheet
Defects on the edges due to sanding or sawing Admitted up to 5 mm from the edge
Grade “C” (IV): All defects are allowed. Plywood has good gluing. For firm packaging and construction.
Categories of defects Permissible amount of defects
Pin knots Permitted
Sound knots Permitted
Other knots:

unsound knots

Permitted up to an individual maximum diameter of 40 mm in unlimited amount
Discolouration and coloured streaks Permitted
Open splits and checks Permitted for an individual maximum width up to 10 mm in unlimited length and amount
Closed splits and checks Permitted
Discolouration and coloured streaks Permitted
Open joints Permitted for an individual maximum width up to 3 mm
Overlap Permitted for a maximum length of 500 mm and no more than 2 per metre of sheet width
Hollows, bumps and imprints Permitted, some
Roughness Permitted
Inserts Unlimited number permitted
Glue penetration Permitted
Defects on the edges due to sawing Admitted up to 5 mm from the edge
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