ISO 17087:2006

INTERNATIONAL ISO
STANDARD 17087
First edition
2006-11-15
Specifications for adhesives used for
finger joints in non-structural lumber
products
Spécifications pour des adhésifs utilisés pour des aboutages dans des
produits en bois non structuraux

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 General principles. 2
5 Apparatus and materials. 3
6 Requirements . 4
7 Test specimens . 4
8 Moisture content and conditioning. 7
9 Test procedures — Flexure and tension . 7
10 Exposure conditions . 10
11 Expression of results . 12
12 Precision. 12
Annex A (informative) Report forms. 13
Annex B (informative) Reading wood failure in finger joints. 20
Bibliography . 22

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17087 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 11, Products.
Based with permission of ASTM, on ASTM D 5572, Standard Specification for Adhesives Used for Finger
Joints in Nonstructural Lumber Products.

iv © ISO 2006 – All rights reserved

INTERNATIONAL STANDARD ISO 17087:2006(E)

Specifications for adhesives used for finger joints in
non-structural lumber products
1 Scope
This International Standard specifies performance levels for adhesives to be used in finger joints in
nonstructural bonded lumber products. Such products include, but are not limited to, interior and exterior
mouldings, window and door components or parts, and bonded lumber panels. Adhesives that meet the
requirements of the various performance classes are considered capable of providing an adequate bond for
use under the conditions described for the class. This specification is intended to be used to evaluate
adhesives as well as the adhesive bonds in the finger joints.
2 Normative references
The following referenced documents are indispensable for the application of this International Standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Verification and calibration of the force-measuring system
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bond
union between materials produced using adhesives
3.2
finger joint
joint formed by bonding two precut members shaped like fingers (see Figure 1)

a)  Horizontal joint b)  Vertical joint
Key
1 face
2 edge
Figure 1 — Finger joint
3.3
dry-use nonstructural adhesive
adhesive capable of producing sufficient strength and durability to make the bonded lumber product
serviceable in nonstructural use, under conditions in which the equilibrium moisture content (EMC) of the
wood does not exceed 16 %
3.4
wet-use nonstructural adhesive
adhesive capable of producing sufficient strength and durability to make the bonded lumber product
serviceable in nonstructural use, under conditions in which the EMC of the wood may be 16 % or greater
3.5
equilibrium moisture content
EMC
moisture content at which wood neither gains nor loses moisture to the surrounding air
NOTE Adapted from ASTM D 9.
3.6
moisture content
MC
amount of water contained in the wood, usually expressed as a percentage of the mass of the oven-dry wood
NOTE Adapted from ASTM D 9.
4 General principles
4.1 Adhesives are classified as dry-use or wet-use. Each classification includes consideration of short-term
in-transit exposure conditions at elevated temperatures up to 104 °C.
NOTE This specification reflects results obtained with laboratory-made specimens compared to those obtained with
industrially manufactured specimens. These finger joints were prepared using previously certified adhesives in
cooperation with a manufacturer or equipment supplier who had the necessary finger joint cutter and assembly equipment.
Such finger joints may vary in geometry and length from manufacturer to manufacturer, and this variation could affect the
performance of the bonded finger joint assembly. Figure 2 depicts a typical finger joint configuration.
4.2 When changes are made in the design of industrially manufactured finger joints, the new design should
preferably be compared to a control design that has been used successfully.
4.3 An industrially made finger joint assembly should preferably be evaluated using the requirements for
compliance with this specification. When this specification is used to evaluate specimens made from
laboratory-made assemblies, the results may not compare favourably with those obtained with specimens
made from industrially made assemblies.
4.4 Test requirements are provided to determine if the adhesive is suitable for dry use or wet use.
4.5 The dry test and exposure conditions and treatments are to evaluate adhesives used in nonstructural
finger joints for typical service conditions.
4.6 The 104 °C test is a more severe test designed to evaluate the product after exposure to short-term
elevated-temperature conditions. This test is intended to simulate conditions that might be experienced in
transit, during further processing or in service conditions.
NOTE Service conditions could typically include stress and time under stress, as well as elevated temperature.
4.7 Procedures are described in sufficient detail to permit duplication in different test laboratories.
To avoid potential problems that would be caused by interrupting the bonding process, the adhesive
performance level should preferably be determined by the finger joint manufacturer prior to handling and early
shipment.
2 © ISO 2006 – All rights reserved

Before beginning the full testing process, the test laboratory should preferably take a representative sample
and check the dry strength first, in order to ensure that the product basically conforms to the dry-strength
performance level certified by the adhesive manufacturer.

Key
a height of joint 33 mm
f length of finger 6 mm
w width of finger tip 1 mm
t
w width of finger base 2 mm
b
s slope of finger 5°
NOTE The dimensions given are examples for a typical horizontal finger joint.
Figure 2 — Example of cross-section of finger joint test specimen
5 Apparatus and materials
5.1 Tensile-testing machine, capable of maintaining a pre-determined constant crosshead rate. The
machine shall be capable of determining a maximum load. The measured strength shall be between 15 % and
85 % of the capacity of the machine. The machine shall permit the measurement and recording of the applied
force with an uncertainty of ± 1 % or better.
The machine shall have a capacity of not less than 9 800 N in compression, shall be equipped for one-third-
span, two-point loading for the flexure test as described in 9.1 and shown in Figure 3, shall be equipped with
grips of sufficient length to hold the specimen firmly, preferably with a minimum length of 63 mm and minimum
width of 19 mm, and shall be located in an atmosphere such that the moisture content of the specimen is not
noticeably altered during testing.
The equipment shall be calibrated regularly in accordance with ISO 7500-1.
It is recommended that the machine be autographic, giving a chart that can be read in terms of millimetres of
crosshead movement as one coordinate and applied force as the other coordinate. It is also recommended
that inertialess equipment be used.
The finger joint specimens to be broken in tension are shorter than those to be broken in flexure.
Accommodation shall be made in the equipment for handling the larger flexure specimen.
5.2 Environmental chamber, capable of conditioning specimens at (23 ± 2) °C and (65 ± 5) % relative
humidity, having a capacity for at least 20 specimens well spaced and supported on racks to allow free air flow.
5.3 Oven(s), with sufficient air circulation to remove moisture from the oven chamber, capable of meeting
all the following temperature requirements: (41 ± 2) °C (see 10.2.3), (65 ± 2) °C (see 10.2.6 and 10.3.3),
(104 ± 2) °C (see 10.2.4, 10.2.5 and 10.3.4) and (110 ± 2) °C (see 10.2.4).
5.4 Specimen-soaking tank, having a capacity meeting the requirements of 10.2.3, so that all of the
specimens are at least 50 mm below the water level for the duration of the soak cycles.
5.5 Specimen-boiling tank, having a capacity meeting the requirements of 10.3.3, so that all of the
specimens are at least 50 mm below the water level for the duration of the boil cycles.
5.6 Vacuum/pressure vessel, having a capacity meeting the requirements of 10.3.5, so that all of the
specimens are at least 50 mm below the water level for the duration of the vacuum/pressure cycles.
5.7 PVDC wrap: poly(vinylidene chloride) film for wrapping test specimens.
6 Requirements
6.1 To demonstrate compliance with this specification, the test adhesive shall be tested for performance in
accordance with Clauses 9 and 10, and it shall meet the requirements in Table 1 for the selected test mode
and performance classification.
6.2 Compliance with this specification shall warrant certification of the adhesive for use on the species of
wood that is used for the tests, or for use on a designated group of species when tested and found to be in
compliance for any one member of said group of species. The designated species groupings for commonly
used woods, as accepted in this specification, are given in Table 2. In the event that the user or supplier of the
adhesive, or both, cannot accept the designated groupings in Table 2, either party shall have the option of
requesting a test on an individual species. Furthermore, the user and supplier may agree to change any of the
wood-failure requirements of Table 1 when applied to tests on group 3 and 4 hardwoods in Table 2.
6.3 The wood-failure requirements listed in Table 1 are given for softwoods and hardwoods.
6.4 An industrially manufactured finger joint may be used to evaluate the adhesive, provided its
construction meets the requirements set forth in Clauses 7 to 10, and the joint is tested against the
requirements in Table 1.
7 Test specimens
7.1 Prepare the finger joint assemblies in cooperation with a wood-products manufacturer, an equipment
manufacturer or a laboratory having all of the proper equipment.
7.2 Use lumber that conforms to the following requirements: maximum slope of grain of 7 % (1 in 14) on
any face or edge; EMC of 8 % to 12 %, preferably brought to 10 % to 12 % MC prior to cutting and bonding;
free of knots and decay; free of machining defects such as chipped grain, feed-roll polish, coarse knife marks
and feed-roll compression; free of drying effects such as case hardening, collapse and splits or checks.
Recommended minimum specific gravities are given in Table 3. Finger joints shall be cut on the day the
assemblies are to be made. See Clause 6 for species compliance rules relative to testing, and Table 2 for
information on the bondability of some species of wood.
7.3 Follow the adhesive manufacturer’s instructions for conditions and procedures for preparing and
applying the adhesive, as well as for assembling, pressing and curing the assembly.
7.4 For each exposure condition within the unique performance classification, a test group shall consist of
20 specimens representing at least four different assemblies with no more than five specimens for each
assembly.
4 © ISO 2006 – All rights reserved

Table 1 — Minimum test requirements
Test mode:
b
Test mode: tension
flexure
d
Wood failure
Subclause
Performance classification and number for
Stress at
Group Individual
a
c e f c
exposure conditions exposure
Strength average minimum rupture
g
description
(min. )
MPa
% %
MPa
Soft- Hard- Soft- Hard-
h h
wood wood wood wood
Dry use:
Cured (dry) 10.2.2 13,8 60 30 30 15 13,8
Three-cycle soak 10.2.3 6,9 30 15 15 ⎯ 6,9
Elevated-temperature test method 1 10.2.4 6,9 ⎯ ⎯ ⎯ ⎯ ⎯
(104 °C)
Elevated-temperature test method 2 10.2.5 6,9 ⎯ ⎯ ⎯ ⎯ ⎯
(104 °C)
Temperature/humidity 10.2.6 5,2 ⎯ ⎯ ⎯ ⎯ ⎯
(65 °C, 16 % EMC)
Wet use:
Cured (dry) 10.3.2 13,8 60 30 30 15 13,8
Boil 10.3.3 11,0 50 25 25 9,7
⎯
Elevated temperature (104 °C) 10.3.4 6,9 ⎯ ⎯ ⎯ ⎯ ⎯
Vacuum/pressure 10.3.5 11,0 50 25 25 ⎯ 9,7
a
Twenty specimens required for each classification and exposure.
b
Parallel to the grain.
c
Tension and flexure results may vary with the species. To be acceptable, a wood shall produce joints able to meet these
requirements.
d
The wood-failure requirements are given for softwoods and hardwoods. Group 3 and 4 hardwoods are listed at 50 % of the
softwood value, with no wood-failure requirement if the calculated value is 15 % or less.
e
For total group of specimens tested.
f
90 % of the specimens tested shall meet or exceed the minimum wood-failure percentages shown. If a zero value is obtained for
any of the specimens, the specimen shall meet the strength requirement.
g
For any individual specimen.
h
See recommended minimum specific gravity in Table 3.

Table 2 — Bondability groupings of commonly used wood
a
Group Hardwoods Softwoods Other
b
Group 1 Alder Cedar, Incense Balsa Hura
Bond easily Aspen Fir, Grand Cativo Purpleheart
Basswood Fir, Noble Courbaril Roble
c
Chestnut, American Fir, Pacific Determa
Cottonwood Fir, White
Magnolia Pine, Eastern white
Willow, Black Pine, Western white
Redcedar, Western
Redwood
Spruce, Sitka
d
Group 2 Butternut Fir, Douglas Afrormosia Meranti (Lauan), Light red
e
Bond well Elm, American Larch, Western Andiroba Meranti (Lauan), White
Elm, Rock Pine, Ponderosa Angelique Meranti (Lauan), Yellow
Hackberry Pine, Sugar Avodire Obeche
Maple, Soft Redcedar, Eastern Banak Okoume
Sweetgum Cedar, Spanish Opepe
Sycamore Iroko Peroba rosa
Tupelo Jarrah Sapele
Walnut, Black Limba Sucupira
Yellow-poplar Mahogany, African Wallaba
Mahogany, True
f
Group 3 Ash, White Cedar, Alaska Angelin Meranti (Lauan), Dark red
Bond satisfactorily Beech, American Cedar, Port Orford Azobe Pau marfim
Birch, Sweet Pine, Southern Benge Pine, Caribbean
Birch, Yellow Bubinga Pine, Parana
Cherry Karri Pine, Radiata
Hickory, Pecan  Ramin
Hickory, True
Madrone
Maple, Hard
c
Oak, Red
c
Oak, White
g
Group 4 Orange, Osage Balata Keruing
Bond with difficulty Persimmon Balau Lapacho
Greenheart Lignumvitae
Kaneelhart Rosewood
Kapur Teak
a
It is recognized that more modern adhesives might lead to different species groupings in regard to difficulty of bonding.
b
Bond very easily with adhesives having a wide range of properties and under a wide range of bonding conditions.
c
Difficult to bond with phenol-formaldehyde adhesives.
d
Bond well with a fairly wide range of adhesives under a moderately wide range of bonding conditions.
e
Wood from butt logs with a high extractive content is difficult to bond.
f
Bond satisfactorily with good-quality adhesives under well-controlled bonding conditions.
g
Satisfactory results require careful selection of adhesives and very close control of bonding conditions; may require special surface
treatment.
6 © ISO 2006 – All rights reserved

Table 3 — Recommended minimum specific gravities by species
a
Specific gravity
Species
g/cm
Cedar, Alaska 0,44
Fir, Douglas (East) 0,48
Fir, Douglas (interior South) 0,46
Fir, White 0,39
Hemlock, Western 0,45
Larch, Western 0,52
Pine, Lodgepole 0,41
Pine, Loblolly 0,51
Pine, Ponderosa 0,40
a
Values are averages based on oven-dry mass and volume at 10 % to 12 %
moisture content.
8 Moisture content and conditioning
8.1 Measuring moisture content
There are several stages in this test method where it is necessary to determine the MC, as follows: on the
lumber before bonding, on the assemblies before cutting into specimens, and on the specimens during
several tests when they have to be dried to a given MC before testing.
Select lumber within the range from 10 % to 12 % MC before bonding (see 7.2). Determine the MC by use of
an electronic moisture meter. After bonding the assemblies in the field, control the MC of the specimens
throughout the testing process.
If needed, condition the assemblies to the original MC ± 1 % by use of an environmental chamber prior to
cutting the specimens.
8.2 Specimen conditioning during the testing process
The allowable variation in MC at the completion of a drying cycle or before testing dry is ± 1 %. For example, if
the MC of the specimen before exposure is 9 %, the acceptable range for testing is 8 % to 10 %. Wood failure
is estimated on specimens after they have been conditioned to less than 8 %, except for the dry test described
in 10.2.2 and 10.3.2, where the specimens have never left the dry state. Wood failure may be read on these
test specimens following the strength testing, with no further conditioning to reduce MC.
9 Test procedures — Flexure and tension
9.1 Testing in flexure
Specimens shall be conditioned in accordance with Clause 8.
From a finger-jointed assembly (see 7.2), cut the flexure-test specimens with sufficient length for the joint to
be centered at midspan as in Figure 3, and with a distance between the reaction points of 24 times the depth
d. Allow at least 25 mm at both ends of the specimen outside the reaction points (see dimension e in Figure 3).
On each edge of the specimen, feather out the finger at the midpoint of the joint, adjusting the width of the
specimen accordingly (see Figure 4).
NOTE In this application, “to feather” means to remove any portion extending beyond the normal surface of the outer
finger so that the stress riser (butt joint effect) is not present on the surface (see Figure 4).
Subject the specimens to the tests for the selected classification (wet use or dry use), or both, in accordance
with the applicable conditions and treatments given in Clause 10. Consult Table 1 for the tests r
...