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Marine Plywood Australian Specification AS 2272
AS/NZS 2272:2006
The Australian Standard AS 2272 specifies a marine
plywood which is probably the best in the world. So what does
AS 2272
say. Unfortunately, we can't publish it here because it is a
copyright document. Instead here is a summary of its more
significant requirements. For any important use, we recommend that
you purchase a copy of the standard to ensure that you have the official
definitions. Grade of Plywood
Surface veneers will be AA or OO and the stress
grade will be taken as F14. When the sheet is laid
flat on a horizontal surface, the maximum distance between the undersize
of the sheet and the surface will be 50mm for sheets less than 7.5mm thick
and 30mm for thicker sheets. A weight of 10kg will flatten sheets of
7.5mm or thiner, and 15kg for sheets thicker than 7.5mm Face Veneer:-
This sets out the specification for an A face
veneer. O face veneer is similar to the core veneer specification,
except that there can only be 4 sound knots and no worm and insect holes.
Defects which are not permitted:-
- Decay and insect attack
- Bark, gum, resin pockets, gum veins, resin streaks and gum
blotches,
- Unfilled holes, splits, open edge joints,
- Knots which are loose, encased and unsound,
- Patches,
- Glue bleed through.
Permitted imperfections :-
- 4 or less filled holes per sheet, each hole smaller than 6mm
across the grain and less than 30 mm square, matche3d in colour to the
surrounding timber.
- Pin knots (less than 2mm in diameter) (any number, provided
appearance is OK) and not more than 4 sound intergrown knots of 4mm
diameter or less per sheet.
- Filled splits and edge joints, each to be a maximum of 2 per face,
maximum of 3mm wide and a maximum area of 450mm square per plywood
face. Filling to be matched in colour to the face.
- Sloping grain if localized and less than 1 in 7.
- Minor roughness associated with permitted imperfections
- Slight natural discolouration and stain
- Low contrast colour variation.
- Veneers of unequal width so long as each is at least 150mm
Thicknesses:-
- Not less than 0.8mm or 1/3rd of the plywood panel thickness,
whichever is less. The face veneer can be two veneers of the
same timber with parallel grain and glued with phenolic resin. Must
not exceed 2.8mm.
Core Veneers:-
Defects which are not permitted:-
- Decay and insect attack
- Bark, gum, resin pockets, gum veins, resin streaks and gum
blotches,
- Unfilled holes, splits, open edge joints,
- Knots which are loose, encased and unsound,
- Patches,
Permitted imperfections :-
- Filled holes. Each hole to be smaller than 6mm across the grain
and less than 30 mm square, matche3d in colour to the surrounding
timber.
- Pin knots (less than 2mm in diameter) (any number, provided
appearance is OK)
- Sound knots, unlimited in number
- Worm and insect holes, not clustered or along the plane of the
veneer
- Filled splits and edge joints, each to be a maximum of 2 per face,
maximum of 3mm wide and a maximum area of 450mm square per plywood
face. Filling to be matched in colour to the face.
- Open splits (core gaps) not wider than the thickness of the
thinnest adjacent veneerand not more than 1 in every 900mm of sheet
edge.
- Sloping grain if localized and less than 1 in 7.
- Minor roughness associated with permitted imperfections
- Slight natural discolouration and stain
- Low contrast colour variation.
- Veneers of unequal width.
Maximum thickness to be 2.8mm
Plywood Panel Construction:-
- Adjacent plies to be laid with their grain at right angles.
- Not less than 40% of the grain and not more than 65% of the grain
can run in any one direction.
- The panel is to be built with veneers on either side of its centre
line matched in thickness, timber type, cutting method and grain
direction.
- The centre veneer can be made up of two veneers glued together
with their grain running in the same direction.
- Core gaps to a maximum size of the thickness of the thinnest
adjacent veneer and not more than 1 in every 900mm of sheet edge.
- Must not have overlaps, pleats..
- Must be free of iron or steel staples or clips and free of tapes
which reduce the sheet waterproofness or strength.
- Only one species of timber may be sued in any one ply.
Permitted Timber Species.
- AS 2272 has a list of permited timber species.
- The most important for our purposes is Hoop Pine, Araucaria
cunninghamii
- There is an additional list of species which may only be used in
the core veneers of AS 2272 plywood. One of the more familiar is
Slash Pine (Pinus elliottii)
- The standard contains a procedure to test if some other timber is
acceptable in AS 2272 plywood.
Glue
- The glue is a Type A glue, that is a phenolic type which conforms
to AS 2754.1
- The bond is to be continuous throughout the sheet, except where
there are permitted imperfections.
Marking
The AS/NZS 2272:2006 requires the following infomation to be included.
- Manufactureres Name and Registered Mark
- the word:- MARINE,
- The grade of the outer plies (face first, back last):- AA or could
be OO
- The bond type:- A Bond
- the stress grade if other than F14
- Detail of any rot treatments
- Formaldehyde emission class:- Eo
- The symbols AS/NZS 2272
e.g. AUSTRAL MARINE F17 AA - A Bond AS/NZS 2272
Enquiries
Please call Boatcraft Pacific
07 3806 1944 ( +617 3806 1944) for how to contact your nearest reseller.
Copyright Boatcraft Pacific Pty.
Ltd. |
