Standard Practice for Surface Preparation and Structural Adhesive Bonding of Precured, Nonmetallic Composite Facings to Structural Core for Flat Shelter Panels

SCOPE
1.1 This practice covers the materials, processes, and quality controls to be used in the manufacture of durable adhesive bonded, nonmetallic faced, flat sandwich panels for rigid wall relocatable shelters.
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are for information only.
1.3 This standard does not purport to address all of 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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09-Apr-2000
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ASTM E1307-00 - Standard Practice for Surface Preparation and Structural Adhesive Bonding of Precured, Nonmetallic Composite Facings to Structural Core for Flat Shelter Panels
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:E1307–00
Standard Practice for
Surface Preparation and Structural Adhesive Bonding of
Precured, Nonmetallic Composite Facings to Structural
Core for Flat Shelter Panels
This standard is issued under the fixed designation E 1307; 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-S-8802 Sealing Compound, Temperature-Resistant,
Integral Fuel Tanks and Fuel Cell Cavities, High-
1.1 This practice covers the materials, processes, and qual-
Adhesion
ity controls to be used in the manufacture of durable adhesive
2.4 Military Handbook:
bonded, nonmetallic faced, flat sandwich panels for rigid wall
MIL-Handbook 337 Adhesive Bonded Aerospace Struc-
relocatable shelters.
tures
1.2 The values stated in SI units are to be regarded as the
standard. The inch-pound units in parentheses are for informa-
3. Terminology
tion only.
3.1 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.1.1 nominal pressure—the intended operating pressure.
safety concerns, if any, associated with its use. It is the
3.1.2 nominal temperature—the intended operating tem-
responsibility of the user of this standard to establish appro-
perature (°C or °F).
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents 4.1 Durable adhesive bonds of composite laminates can be
obtained reliably only through proper selection and careful
2.1 ASTM Standards:
control of the materials used and the steps in the bonding
C 297 Test Method for Tension Strength of Flat Sandwich
2 process. The preparation of the composite laminates to obtain
Constructions in Flatwise Plane
surfaces with appropriate characteristics is a critical step.
E 865 Specification for Structural Film Adhesives for Hon-
3 Improper surface preparation can produce seemingly accept-
eycomb Sandwich Panels
able bonds that can degrade rapidly with time. This practice
E 990 Specification for Core-Splice Adhesive for Honey-
3 describes how properly prepared surfaces can be obtained.
comb Sandwich Shelter Panels
4.2 The formation of reproducible, durable, adhesive bonds
E 1091 Specification for Nonmetallic Honeycomb Core for
3 in structural units requires great care in the selection of
Use in Shelter Panels
materials, the preparation of the surfaces of the parts to be
E 1749 Terminology Relating to Rigid Wall Relocatable
3 bonded, the fit of parts, and the performance of the steps in the
Shelters
bonding process. Experience has shown that adhesive bonding
2.2 Federal Standard:
carried out in accordance with this practice produces reproduc-
FED STD 209 Clean Room and Work Station Require-
4 ible bonds.
ments
2.3 Military Standard:
5. Materials
5.1 Materials—Materials shall be as specified herein or as
ThispracticeisunderthejurisdictionofASTMCommitteeE-6onPerformance specified in the contract. All materials shall be stored and
of Buildings and is the direct responsibility of Subcommittee E06.53 on Materials
handled in such a manner as to provide protection against
and Processes for Durable Rigidwall Relocatable Structures.
degrading environments and mechanical damage.
Current edition approved April 10, 2000. Published June 2000. Originally
5.2 Composite Reinforcement and Resin— The composite
published as E 1307 – 89. Last previous edition E 1307 – 95.
Annual Book of ASTM Standards, Vol 15.03.
reinforcement and resin shall meet the requirements specified
Annual Book of ASTM Standards, Vol 04.11.
in the procurement document.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1307–00
5.3 Peel Ply Fabric—Anonreuseable peel ply shall be used. two facings of press platens during lamination will be equal
Closely woven fabric of nylon, polyester, or glass has been and uniform within 4 % of their nominal temperature. The
found suitable.The peel ply fabric must be compatible with the
pressure equipment used for curing the panels shall be capable
manufacturing process. of applying greater than 140 kPa (20 psi) and 150°C (300°F)
5.4 Precured Facings—The facings shall be certified as
overtheentirepanelsurface.Platensshallbeflattowithin0.17
complying with the reinforcement, resin binder, resin content,
mm/m (0.002 in./ft).The pressure equipment shall be equipped
and thickness requirements of the procurement document.
with temperature and pressure recorders and controls that
Facings shall be free of defects that may adversely affect the
accurately control heat-up rate, pressure application, dwell
structural integrity of the bonded panel.
time, cool down (when required), and pressure removal. The
5.5 Core—The core material shall be as specified in Speci-
pressure equipment shall also be equipped with suitable
fication E 1091 or the procurement document and shall meet
devices (for example, caul sheets) that facilitate moving the
the requirements of the applicable document.
panel layup into the press without misaligning the layup.
5.6 Structural Film Adhesive—The adhesive shall conform
7.1.1 Calibrations, Temperature, and Pressure Require-
to the requirements of Specification E 865. It shall be stored in
ments and Controls—Gages shall be calibrated at least every
accordance with the manufacturer’s recommendations.
six months by an accredited independent laboratory or by the
5.7 Core Splice Adhesive—The core splice adhesive shall
manufacturer if approved by the purchaser. The latest calibra-
conform to the requirements of Specification E 990. It shall be
tion certificate shall be attached to the equipment near each
stored in accordance with the manufacturer’s recommenda-
gage. It shall be demonstrated that the actual bonding pressure
tions.
is within 10 % of the nominal pressure. It shall also be
demonstrated that the average temperatures of the top and
6. Facilities
bottom panel facings during the bonding process are equal and
6.1 PanelAssembly LayupArea—Thepanelassemblylayup
uniform to within 4 % of the nominal temperature. Thermo-
area is an enclosed, environmentally controlled area (ECA)
couples placed within 150 mm (6 in.) of each corner and at the
that is continuously controlled for temperature, relative humid-
center of each facing shall be used to demonstrate the unifor-
ity, and concentration of airborne particles. The ECA shall be
mity of the temperature. Compliance of the equipment with
maintained at a temperature of 24 6 6°C (75 6 10°F) and not
these requirements shall be verified at intervals not exceeding
morethan50 %relativehumidity.Thetemperatureandrelative
six months. A permanent record of the pressure, time, and
humidity shall be recorded continuously. All incoming and
temperature measurements during bonding compliance checks
recirculated air shall be filtered to control airborne particles.
shall be maintained. All calibrations must be traceable to the
The air handling equipment shall provide at least five air
National Institute of Standards and Technology.
changes per hour in the ECA. The filters shall ensure that the
7.2 Autoclave—The autoclave equipment for bonding shel-
particlecountwithintheECAwillnotexceed7 3 10 particles
ter panels shall be large enough to permit the bonding of entire
per cubic metre (200 000 particles per cubic foot) of size 1 µm
shelter panel assemblies in one step. The autoclave shall be
and larger. The air pressure differential between the ECA and
equipped with vacuum gages and temperature and pressure
adjacent areas shall be monitored continuously and recorded at
recorders that accurately control heat-up rate, pressure appli-
least twice weekly. The air pressure in the ECA shall be
cation, dwell time, cool down, and pressure removal. Vacuum
maintainedabovethatofadjacentareasbyaminimumof50Pa
venting facilities shall be provided. The autoclave equipment
(0.015 in. Hg). The particle count shall be monitored in
used for curing the panels shall be capable of applying greater
accordance with FED STD-209. The recorders shall be cali-
than 140 kPa (20 psi) and 150°C (300°F). The manufacturer
brated every six months. The ECA shall be conspicuously
shall provide calibration and test data demonstrating that the
identified at all entrances as “Limited Access”. Unnecessary
traffic within the ECA shall not be permitted. Eating and temperature was maintained within 4 % of the nominal tem-
smoking within the ECA shall not be permitted and the ECA perature and the pressure was maintained within 10 % of the
shall be so posted. All material, tools, and equipment used in operating pressure.
the ECA shall be clean, low shed, and free from lint, oil, and
7.3 Testing Equipment—The supplier shall have available
grease. The use and application of oil, grease, mold release
sufficient testing equipment to ensure that all process control
agents, or other possible contaminants within the ECAshall be
specimen preparation and testing required by this practice can
prohibited. The interior, exposed surfaces of the ECA shall be
beaccomplished.Allcalibrationsoftestequipmentrequiredby
nonshedding and easily cleaned to minimize dust generation.
this practice shall be traceable to the National Institute of
Any particle-generating preparations such as removal of peel
Standards and Technology (NIST).
ply, insertion of foam into honeycomb core, or cleaning must
be accompanied by filtered vacuum when performed in the
8. Preparation of Composite Facings
ECA.
8.1 The composite reinforcement, number of plies, resin,
7. Equipment
and cure cycle shall meet the requirements as specified in the
shelter specification.
7.1 Platen Press—Pressure equipment for bonding of shel-
ter panels shall be large enough to permit the bonding of the 8.2 Peel Ply— A peel ply shall be included as the surface
layer for the side of the precured skin that will be later bonded.
total panel in one step. The manufacturer shall provide cali-
bration and test data demonstrating that the temperature on the The peel ply shall extend past all edges.
E1307–00
8.3 Peel Ply Removal—Prior to bonding, remove the peel of Specification E 990. The core splicing method and adhesive
ply from the faying surface to provide a clean, high-area used shall be such that the shear strength of the splice shall be
surface ideal for bonding. Removal shall be accomplished in equal to or greater than the core shear strength. Any crushed
the ECA. corners and edges of the core sheets shall be repaired and the
sheet resquared prior to splicing and lamination. Where the
9. Quality Assurance of Composite Facings
shelter design requires that all framing members be bonded
9.1 Handling—Parts with the peel ply removed or being
simultaneously with panel bonding, the core shall fit into the
removed shall be handled using clean gloves or other methods
panel layup such that the gap between the core and the framing
to prevent surface contamination.
members is no more than 1.5 mm ( ⁄16 in.). Adhesive meeting
9.2 Marking—All processed parts shall be marked with the
the requirments of Specification E 990 must fill this gap and
date and time of manufacture. If the surface with the peel ply
provide a good bond to the framing members. The volatile
removed must be marked, marking shall be lightly scribed.
content of the core (including moisture) at the time of panel
9.3 Written Process Procedure—Each processor shall keep
assembly shall not exceed 2% by mass for honeycomb and
a written record of the date and time the peel ply was removed,
balsa wood when tested in accordance with 15.1. Other core
the time placed into the ECA, and the time the facing was
materials shall meet the requirements specified in the design
bonded.
specification.
9.4 Visual Inspection—After removal of the peel ply, the
10.5 Application of Adhesive—The procedures for applica-
faying surface shall be inspected for defects as defined by the
tion of adhesive shall be in conformance with the manufactur-
procurement document. Any defects shall be recorded.
er’s instructions in the process specification approved by the
purchaser of the adhesive. Film adhesives shall be brought to
10. Shelter Panel Construction
the temperature of the panel assembly layup room prior to
10.1 The matrix resin, fiber reinforcement, thickness of the
removal of the protective wrapper.
facings, edge closure details, core type, and the weights and
10.6 Assembly and Handling of Panel Components—The
sizes of the panels shall be as specified in the procurement
method of handling the core with the facings shall ensure that
document. Unless otherwise specified, the allowable deviation
there will be no relative movement between core and facing
from flatness of the bonded panel shall be within 1.5 mm ( ⁄16
duringandafterthebondingofcomponents.Panelcomponents
in.) when measured as specified in 15.3.1 against the concave
shall not vary in thickness sufficiently to cause unacceptable
side of the panel. With the panel in a horizontal position, lay
pressure deviations on the panel from nominal pressure during
the straight edge on the panel surface and measure the
bonding.
maximum gap between the straightedge and the panel. The
10.7 Bonding Operation—The bonding pressure (gage)
facing surfaces may contain local bulges or depression within
shall be recorded for each bonding cycle. The pressure shall be
the allowable flatness tolerance specified above.
maintained within 10 % of the nominal pressure during the
10.2 Edge Closures and Framing Members— The edge
bonding cycle. Charts relating equipment gage pressure to
closures and framing members shall be as specified in the
panel size for the required bonding pressure shall be attached
shelter design specification. When the shelter design requires
to each pressure application device. The bonding temperature
the edge closures and framing members to be bonded simul-
foreachbondingcycleshallberecordedinapermanentrecord.
taneously with panel bonding, the edge closures and framing
members shall be bonded to the facings with the adhesive 10.7.1 Platen Press Bonding—Platen press equipment that
specified in 5.6 and to the core with adhesive specified in 5.7. is used for structural adhesive bonding of precured flat com-
10.3 Preparation of Composite Facing an
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