ASTM E874-98
(Practice)Standard Practice for Adhesive Bonding of Aluminum Facings to Nonmetallic Honeycomb Core for Shelter Panels
Standard Practice for Adhesive Bonding of Aluminum Facings to Nonmetallic Honeycomb Core for Shelter Panels
SCOPE
1.1 This practice describes the materials, processes, and quality controls to be used in the manufacture of adhesive-bonded, aluminum-faced, nonmetallic-honeycomb-core sandwich panels for tactical shelters.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: E 874 – 98
Standard Practice for
Adhesive Bonding of Aluminum Facings to Nonmetallic
Honeycomb Core for Shelter Panels
This standard is issued under the fixed designation E 874; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope MIL-STD-105 Sampling Procedures and Tables for Inspec-
tion by Attributes
1.1 This practice describes the materials, processes, and
MIL-STD-907B Military Standard Engineering and Design
quality controls to be used in the manufacture of adhesive-
Criteria for Rigid Wall Shelters
bonded, aluminum-faced, nonmetallic-honeycomb-core sand-
2.3 Federal Standards:
wich panels for tactical shelters.
Fed. Std. No. 209 Clean Room and Work Station Require-
1.2 The values stated in inch-pound units are to be regarded
ments, Controlled Environment
as the standard. The values given in parentheses are for
information only.
3. Terminology
1.3 This standard does not purport to address the safety
3.1 Definitions of Terms Specific to This Standard:
concerns, if any, associated with its use. It is the responsibility
3.1.1 excessive corrosion, n—surface corrosion that is not
of the user of this standard to establish appropriate safety and
removed by cleaning as described in Practice E 864.
health practices and determine the applicability of regulatory
3.1.2 gouge, n—a surface defect in which material has been
limitations prior to use.
removed and that causes a decrease in strength in a highly
2. Referenced Documents stressed area.
3.1.3 nominal pressure, n—the intended operating pressure.
2.1 ASTM Standards:
3.1.4 nominal temperature, n—the intended operating tem-
B 209 Specification for Aluminum and Aluminum-Alloy
perature.
Sheet and Plate
3.1.5 tapping test, n—a nondestructive evaluation proce-
C 297 Test Method for Tensile Strength of Flat Sandwich
dure for detecting panel delamination in which the outer skin of
Constructions in Flatwise Plane
the panels is tapped with a hammer or coin.
D 1781 Test Method for Climbing Drum Peel for Adhe-
3.1.5.1 Discussion—Changes in acoustic emissions result-
sives
ing from tapping can be associated with delamination and
E 864 Practice for Surface Preparation of Aluminum Alloys
nondelaminated sections of panel.
to Be Adhesively Bonded in Honeycomb Shelter Panels
E 865 Specification for Structural Film Adhesives for Hon-
4. Significance and Use
eycomb Sandwich Panels
4.1 The formation of reproducible, durable-adhesive bonds
E 866 Specification for Corrosion-Inhibiting Adhesive
in structural units requires great care in the selection of
Primer for Aluminum Alloys to Be Adhesively Bonded in
5 materials, the preparation of the surfaces of the parts to be
Honeycomb Shelter Panels
bonded, and the performance of the steps in the bonding
E 990 Specification for Core-Splice Adhesive for Honey-
5 process. Experience has shown that adhesive bonding carried
comb Sandwich Shelter Panels
out in accordance with this practice produces relatively repro-
E 1091 Specification for Nonmetallic Honeycomb Core for
5 ducible bonds.
Use in Shelter Panels
2.2 Military Standards:
5. Facilities
5.1 Panel-Assembly-Layup Area—The panel-assembly-
lay-up area is an enclosed, environmentally controlled area that
This practice is under the jurisdiction of ASTM Committee E-6 on Performance
of Buildings and is the direct responsibility of Subcommittee E06.53 on Materials
is continuously controlled for temperature, relative humidity,
and Processes for Durable Rigid Wall Relocatable Structures.
Current edition approved Sept. 10, 1998. Published November 1998. Originally
published as E 874 – 82. Last previous edition E 874 – 96. Copies of specifications, standards, and drawings required by the manufacturer
Annual Book of ASTM Standards, Vol 02.02. in conjunction with specific procurements, or information about appropriate sources
Annual Book of ASTM Standards, Vol 15.03. of these documents, should be obtained from the purchaser.
4 7
Annual Book of ASTM Standards, Vol 15.06. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 04.11. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 874
and concentration of airborne particles. The environmentally panel layup into the press without misaligning the layup.
controlled area shall be maintained at a temperature of
6.1.1 Calibrations, Temperature and Pressure Require-
75 6 10°F (24 6 6°C) and not more than 50 % relative hu-
ments, and Controls—Gages shall be calibrated every six
midity. The temperature and relative humidity shall be re-
months by an accredited independent laboratory or by the
corded continuously. All incoming and recirculated air shall be
manufacturer if approved by the purchaser. The latest calibra-
filtered to control airborne particles. The air handling equip-
tion certificate shall be attached to the equipment near each
ment shall provide at least five air changes per hour in the
gage. It shall be demonstrated that the actual bonding pressure
environmentally controlled area. The filters shall ensure that
is within 10 % of the nominal pressure. It shall also be
the particle count within the environmentally controlled area
demonstrated that the average temperatures of the top and
3 6 3
will not exceed 200 000 particles/ft (7 3 10 particles/m )of
bottom panel facings during the bonding process are equal and
size 1 μm and larger. The air pressure differential between the
uniform to within 4 % of the nominal temperature. Thermo-
environmentally controlled area and adjacent areas shall be couples placed at each corner and at the center of each facing
monitored continuously and recorded at least twice weekly.
shall be used to demonstrate the uniformity of the temperature.
The air pressure in the environmentally controlled area shall be Compliance of the equipment with these requirements shall be
maintained above that of adjacent areas by a minimum of 0.015
verified at intervals not exceeding six months. A permanent
in. H O (3.7 Pa). The particle count shall be monitored in record of the pressure, time, and temperature measurements
accordance with Fed. Std. No. 209. The recorders shall be
during bonding shall be maintained. All calibrations must be
calibrated every six months. The environmentally controlled traceable to the National Institute of Standards and Technology.
area shall be conspicuously identified at all entrances as limited
6.2 Testing Equipment—The supplier shall have available
access. Unnecessary traffic within the environmentally con-
sufficient testing equipment to ensure that all process-control
trolled area shall not be permitted. Eating and smoking within
specimen preparation and testing required by this practice can
the environmentally controlled area shall not be permitted and
be accomplished without unnecessarily delaying production.
the environmentally controlled area shall be so posted. All
All calibrations of test equipment required by this practice shall
materials, tools, and equipment used in the environmentally
be traceable to the National Institute of Standards and Tech-
controlled area shall be clean, low shed, and free of lint, oil,
nology.
and grease. The application of oil, grease, mold release agents,
or other possible contaminants within the environmentally
7. Materials
controlled area shall be prohibited. The interior, exposed
7.1 Materials shall be as specified herein or as specified in
surfaces of the environmentally controlled area shall be non-
the contract. All materials shall be stored and handled in such
shedding and easily cleaned. The floor shall be sealed and
manner as to provide adequate protection against degrading
cleaned daily to minimize dust generation. No preparations
environments and mechanical damage.
such as insertion of foam into honeycomb core, or cleaning
7.2 Aluminum:
other than by filtered vacuum, shall take place in the environ-
7.2.1 Facings—The facings shall be aluminum alloy con-
mentally controlled area. No core cutting shall be allowed in
forming to Specification B 209 and shall be certified as
the environmentally controlled area other than that required for
complying with the alloy, temper, and thickness requirements
integral-panel cutouts involving total thickness of the core to
of the shelter specification. Facings shall be free of excessive
precut skin openings, core repair, or minor trimming.
corrosion, oil canning (snap-buckling), dents, gouges, or other
5.2 Primer Application Area—The primer-application area
defects that may adversely affect the structural integrity of a
shall be separated from the cleaning tanks, manufacturing area,
bonded panel. The manufacturer’s certification or reports of
and other areas of potential contamination. All air furnished to
tests for mechanical properties and chemical composition shall
this area shall be filtered, and compressed air used shall be
be included with each shipment.
oil-free.
7.2.2 Preparation of Aluminum-Alloy Parts for Bonding—
6. Apparatus
The aluminum-alloy parts used in the manufacture of honey-
comb panels shall be prepared for bonding in accordance with
6.1 Pressure Equipment—Pressure equipment for bonding
Practice E 864.
of shelter panels shall be large enough to permit the bonding of
7.3 Honeycomb Core—The honeycomb-core material shall
the total panel in one step. The manufacturer shall provide
be as specified in the shelter specification and shall meet the
calibration and test data demonstrating that the temperature on
requirements of Specification E 1091. It shall be stored in its
the two facings of press platens during lamination will be equal
shipping container in a segregated area away from traffic
and uniform within 4 % of their nominal temperature. The
congestion until processing for panel layup.
pressure equipment used for curing the panels shall be capable
7.4 Adhesives—The structural film and core splice adhe-
of applying greater than 20 psi (138 kPa) and 300°F (150°C)
over the entire panel surface. Platens shall be flat to within sives shall conform to Specifications E 865 and E 990, respec-
tively. They shall be stored in accordance with the manufac-
0.002 in./ft (0.17 mm/m). The pressure equipment shall be
turer’s recommendation.
equipped with temperature and pressure recorders and controls
that accurately control heat-up rate, pressure application, dwell 7.4.1 Qualification of Adhesive System—The panel manu-
time, cool down (when required), and pressure removal. The facturer is responsible for ensuring that the adhesive system
pressure equipment shall also be equipped with suitable used in the manufacture of panels under this practice is
devices (for example, caul sheets) that facilitate moving the qualified to meet Specifications E 865 and E 990.
E 874
7.5 Primer—The adhesive primer shall conform to Specifi- the seam between pieces shall be spliced so that uniformity of
cation E 866. thickness is maintained across the seam. The core-splicing
7.6 Thermal Barriers—Thermal barriers shall conform to
material shall conform to Specification E 990 and must be
the purchaser’s requirements. impermeable to water and serve as a barrier to water migration.
The core-splicing method and adhesive used shall be such that
NOTE 1—Thermal barriers are bonded between the skin and metal-edge
the shear strength of the splice shall be equal to or greater than
members to prevent a thermal short between exterior and interior skins.
the core-shear strength. Any crushed corners and edges of the
8. Panel Construction
core sheets shall be removed and the sheet resquared prior to
8.1 The alloy, temper, and thickness of the facings, edge
splicing and lamination. Where the shelter design requires that
closure details, core type, and the weights and sizes of the
all framing members be bonded simultaneously with panel
panels shall be as specified in the design specification. Panels
bonding, the core shall fit into the panel lay-up such that the
shall not have any defects, bulges, depressions, or dents with
gap between the core and the framing members is no more than
2 2
an area greater than 8 in. (5200 mm ) or deeper than 0.040 in.
0.125 in. (3.2 mm) from the framing members. The volatile
(1.0 mm). The total allowable area of defects per panel shall
content of the honeycomb core (including moisture) at the time
not exceed 0.1 % of panel area per side. Panels exceeding
of panel-assembly lay-up shall not exceed 2 % by mass when
0.1 % defect area may be subjected to rework procedure agreed
tested in accordance with 10.4.2.
upon between the manufacturer and the customer. Panels shall
8.5 Application of Primer and Adhesive—The prepared
not be bowed or warped nor shall there be any deviation from
aluminum facings and framing members shall be free of
total flatness of the panel greater than 0.016 in./ft (1.3 mm/m).
contaminants before application of the primer and the adhe-
The allowable deviation from flatness (warpage) shall be
sive. Application of primer shall be carried out in the primer
determined by applying a straight-edge, as specified in 10.6.1,
application area. Parts requiring identification shall be marked
against the concave side of the panel with the opposite side
with inks or methods approved for bonding. The faying surface
lying on a flat surface and measuring the maximum gap
of each facing prior to and following the application of primer
between the straightedge and the panel.
shall exhibit uniform properties as determined by Specification
8.2 Edge Closures and Framing Members—These shall be
E 866. The procedures, equipment for application, and the
as specified in the shelter-design specification. On pre-existing
amount of primer and adhesive applied shall be in conformance
designs, process the material in accordance with pre-existing
with the manufacturer’s instructions or the process specifica-
design configuration/specification requirements unless other-
tion approved by the purchaser. The thickness of primer
wise directed by the procuring activity. When the aluminum
applied per unit area of facing shall be measured at least once
edge closures are to be bonded, they shall be treated in
each working shift and whenever a change of working person-
accordance with Practice E 864. When the shelter design
nel is made. Apply the primer to the clean, prepared faying
requires th
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