ASTM E1801-21

Standard Practice for Adhesive Bonding of Aluminum Facings in Foam and Beam Type Shelters

SIGNIFICANCE AND USE
4.1 The formation of reproducible, durable adhesive bonds in structural units requires great care in the performance of the steps in the bonding process. Experience has shown that adhesive bonding carried out in accordance with this practice produces reproducible adhesive bonds. This practice is applicable to both the Type 1, 160 °F (71 °C), and Type 2, 200 °F (93 °C), elevated humidity service type of foam and beam shelter.
SCOPE
1.1 This practice covers the materials, processes, and quality controls to be used in the manufacture of adhesive-bonded, aluminum-faced, foam core sandwich panels for tactical shelters.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jan-2021
• ICS: 83.180 - Adhesives
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.53 - Materials and Processes for Durable Rigidwall Relocatable Structures

Relations

• Refers: ASTM E1730-19 - Standard Specification for Rigid Foam for Use in Structural Sandwich Panel Cores
• Effective Date: 01-Jul-2019
• Refers: ASTM E1793-19 - Standard Practice for Preparation of Aluminum Alloy for Bonding in Foam and Beam Type Transportable Shelters
• Effective Date: 01-Jul-2019
• Refers: ASTM E1749-18 - Standard Terminology Relating to Rigid Wall Relocatable Shelters
• Effective Date: 01-Oct-2018
• Refers: ASTM E1730-15 - Standard Specification for Rigid Foam for Use in Structural Sandwich Panel Cores
• Effective Date: 01-May-2015
• Refers: ASTM E631-15 - Standard Terminology of Building Constructions
• Effective Date: 01-Mar-2015
• Refers: ASTM E631-14 - Standard Terminology of Building Constructions
• Effective Date: 01-Nov-2014
• Refers: ASTM E1793-11 - Standard Practice for Preparation of Aluminum Alloy for Bonding in Foam and Beam Type Transportable Shelters
• Effective Date: 01-Sep-2011
• Refers: ASTM B209-10 - Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
• Effective Date: 01-Nov-2010
• Refers: ASTM E1749-10 - Standard Terminology Relating to Rigid Wall Relocatable Shelters
• Effective Date: 01-Nov-2010
• Refers: ASTM E1730-09 - Standard Specification for Rigid Foam for Use in Structural Sandwich Panel Cores
• Effective Date: 01-Nov-2009
• Refers: ASTM E1800-08 - Standard Specification for Adhesive for Bonding Foam Cored Sandwich Panels (160°F Elevated Humidity Service), Type I Panels
• Effective Date: 01-Nov-2008
• Refers: ASTM E1794-08 - Standard Specification for Adhesive for Bonding Foam Cored Sandwich Panels (200°F Elevated Humidity Service), Type II Panels
• Effective Date: 01-Nov-2008
• Refers: ASTM B209-07 - Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
• Effective Date: 01-Aug-2007
• Refers: ASTM B209-06 - Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
• Effective Date: 01-Jul-2006
• Refers: ASTM E631-06 - Standard Terminology of Building Constructions
• Effective Date: 01-Jun-2006

Overview

ASTM E1801-21 provides a standardized practice for the adhesive bonding of aluminum facings to foam cores in the manufacturing of sandwich panels, specifically for tactical and relocatable shelters. Developed by ASTM International, this standard outlines essential materials, process controls, and quality assurance measures to ensure reliable, durable, and reproducible adhesive bonds. It applies to both Type 1 (160 °F / 71 °C elevated humidity service) and Type 2 (200 °F / 93 °C elevated humidity service) shelter panels. Adherence to this practice promotes consistency, structural integrity, and longevity in shelter panel fabrication.

Key Topics

• Material Requirements

  • Specifies the use of aluminum alloy conforming to ASTM B209 for panel facings.
  • Foam core materials must meet ASTM E1730.
  • Adhesives used must comply with ASTM E1800 (Type 1) and ASTM E1794 (Type 2).

• Preparation and Handling

  • Careful cleaning and preparation of all components, particularly aluminum facings, to ensure optimal surface conditions for bonding.
  • Use of clean cotton gloves and maintenance of contaminant-free assembly areas.
  • Strict guidelines on storage and handling to prevent material degradation and physical damage.

• Bonding Process

  • Detailed requirements for adhesive application, including quantity, uniform coverage, and timing before pressure application.
  • Defined assembly and cure cycles for both Type 1 and Type 2 panels, with specific temperature and pressure parameters.
  • Calibration and control of press equipment and environmental factors in assembly and post-curing areas.

• Quality Assurance

  • Ongoing process control through routine calibration, adhesive mix checks, and standardized inspection protocols.
  • Panel inspections, tapping tests, and visual checks to detect defects like delaminations or surface irregularities.
  • Requirements for documentation and certification from manufacturers to confirm compliance with the standard.

Applications

ASTM E1801-21 is primarily applied in the manufacture of tactical shelters, including but not limited to:

• Military Shelters: Ensures structurally sound and weather-resistant panels for mobile and field-deployable shelters.
• Relocatable Buildings: Supports quality in temporary or transportable modular structures, such as disaster relief or temporary command centers.
• Industrial Enclosures: Provides for the fabrication of robust panels used in various portable or removable containment solutions.

By following ASTM E1801-21, manufacturers can achieve higher repeatability and reliability in their panel production processes, reducing the risk of bond failure and enhancing long-term performance under adverse conditions, including elevated humidity and temperature.

Related Standards

• ASTM B209 - Aluminum and Aluminum-Alloy Sheet and Plate
• ASTM E631 - Terminology of Building Constructions
• ASTM E1730 - Specification for Rigid Foam for Use in Structural Sandwich Panel Cores
• ASTM E1749 - Terminology Relating to Rigid Wall Relocatable Shelters
• ASTM E1793 - Preparation of Aluminum Alloy for Bonding in Foam and Beam Type Transportable Shelters
• ASTM E1794 - Adhesive for Bonding Foam Cored Sandwich Panels (200°F Service)
• ASTM E1800 - Adhesive for Bonding Foam Cored Sandwich Panels (160°F Service)
• Federal QQ-A-250/11 - Aluminum Alloy 6061–T6 Plate and Sheet

Summary

By detailing a comprehensive and reproducible approach for adhesive bonding of aluminum facings in foam-core sandwich panels, ASTM E1801-21 supports quality, safety, and performance in critical applications such as tactical shelters and relocatable buildings. Using this standard helps ensure durability, consistency, and compliance with both industry and defense requirements for structural bonding in shelter fabrication.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1801 − 21
Standard Practice for
Adhesive Bonding of Aluminum Facings in Foam and Beam
Type Shelters
This standard is issued under the fixed designation E1801; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope E1793 Practice for Preparation of Aluminum Alloy for
Bonding in Foam and Beam Type Transportable Shelters
1.1 This practice covers the materials, processes, and qual-
E1794 Specification for Adhesive for Bonding Foam Cored
ity controls to be used in the manufacture of adhesive-bonded,
Sandwich Panels (200°F Elevated Humidity Service),
aluminum-faced, foam core sandwich panels for tactical shel-
Type II Panels
ters.
E1800 Specification for Adhesive for Bonding Foam Cored
1.2 The values stated in inch-pound units are to be regarded
Sandwich Panels (160°F Elevated Humidity Service),
as standard. The values given in parentheses are mathematical
Type I Panels
conversions to SI units that are provided for information only 3
2.2 Federal Standard:
and are not considered standard.
QQ-A-250/11 Alumium Alloy 6061–T6 Plate and Sheet
1.3 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 For definitions of general terms related to building
mine the applicability of regulatory limitations prior to use.
construction used in this practice, refer to see Terminology
1.4 This international standard was developed in accor-
E631, and for general terms related to rigid wall relocatable
dance with internationally recognized principles on standard-
shelters, refer to Terminology E1749.
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.1 The formation of reproducible, durable adhesive bonds
Barriers to Trade (TBT) Committee.
in structural units requires great care in the performance of the
steps in the bonding process. Experience has shown that
2. Referenced Documents
adhesive bonding carried out in accordance with this practice
produces reproducible adhesive bonds. This practice is appli-
2.1 ASTM Standards:
cable to both the Type 1, 160 °F (71 °C), and Type 2, 200 °F
B209 Specification for Aluminum and Aluminum-Alloy
(93 °C), elevated humidity service type of foam and beam
Sheet and Plate
shelter.
E631 Terminology of Building Constructions
E1730 Specification for Rigid Foam for Use in Structural
5. Facilities
Sandwich Panel Cores
5.1 PanelAssembly LayupArea—The panel assembly layup
E1749 Terminology Relating to Rigid Wall Relocatable
area shall be a ventilated area maintained at a minimum
Shelters
temperature of 68 °F (20 °C). The area shall be free of oils,
grease, silicone, lint, or other contaminants detrimental to the
production of adhesive bonds.
This practice is under the jurisdiction of ASTM Committee E06 on Perfor-
mance of Buildings and is the direct responsibility of Subcommittee E06.53 on
5.2 Post-Curing Rooms—The post-curing rooms shall pro-
Materials and Processes for Durable Rigidwall Relocatable Structures.
vide a uniform temperature distribution over all panels and
Current edition approved Feb. 1, 2021. Published February 2021. Originally
over all portions of the panels exposed for post-curing. The
approved in 1996. Last previous edition approved in 2015 as E1801 – 15. DOI:
10.1520/E1801-21. total temperature range shall be no more than 25 °F (14 °C).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
the ASTM website. Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1801 − 21
6. Apparatus 7.2.2.2 Type 2, 200 °F (93 °C), Elevated Humidity Service
Shelters—Thealuminum-alloypartsusedinthemanufactureof
6.1 Pressure Equipment—Pressure equipment for bonding
Type 2 foam and beam panels shall be prepared for bonding in
of shelter panels shall be large enough to permit the bonding of
accordance with Practice E1793 and Specification E1794. The
a complete panel in one step. The manufacturer shall provide
surface resistance of the cleaned parts, or test coupons of the
calibration and test data demonstrating that the temperature on
same alloy and cleaned by the same process, shall be no more
the two facings of the press platens during bonding will be
than 100 microhms when measured under a nominal electrode
equal and uniform within 65°F (63 °C) of the indicated
force of 600 psi 6 25 psi (4.14 MPa 6 1.7 MPa) and a current
temperature. The platens shall be flat to within 0.003 in./ft
of 10 amperes 6 0.2 amperes. Five coupons shall be tested
(0.08 mm/305 mm) and shall be smooth having a maximum
during each4hof cleaning operations.
surface roughness of 125 rms.The pressure equipment shall be
7.3 Foam Core—The foam core material shall be as speci-
equipped with temperature and pressure recorders and controls
fied in the shelter specification and shall meet the requirements
that accurately control heat-up, pressure applied, and dwell
of Specification E1730. Manufacturers’certification or reports
time.
of tests for conformance to this specification shall be available
6.2 Calibrations, Temperature and Pressure Requirements,
or included with each shipment, or both.
and Controls—Gages shall be calibrated every six months by
7.4 Adhesives—The adhesive shall conform to Specification
an accredited independent laboratory or by the panel manufac-
E1800 for Type 1 shelters or Specification E1794 for Type 2
turer if approved by the purchaser. All calibrations shall be
shelters. The adhesive shall be stored and used in accordance
traceabletotheNationalInstituteofStandardsandTechnology.
with the manufacturer’s recommendations. Manufacturers’
The latest calibration certificate shall be attached to the
certification or reports of tests for conformance to this speci-
equipment near each gage. Thermocouples placed at each
fication shall be available or included with each shipment, or
corner and at the center of each facing shall be used to
both.
demonstrate the uniformity of the temperature. A permanent
record of the pressure, time, and temperature during bonding
7.5 Preparation of Nonmetallic Parts Prior to Bonding—If
shall be maintained.
necessary, all plastic, wood, and foam parts used in the
construction of these shelters shall be prepared for bonding
6.3 Calibration of Testing Equipment—Calibration of the
prior to the application of the adhesive. Parts with gouges,
required testing equipment shall be done in accordance with
broken edges, splits or cracks, or other defects shall not be
the equipment manufacturer’s instructions. All calibrations of
used.
testequipmentrequiredbythispracticeshallbetraceabletothe
National Institute of Standards and Technology.
8. Bonding and Curing
8.1 Preparation of Materials Bonding—All cutting,
7. Materials
trimming, and sizing of aluminum, plastic, and wood parts
7.1 The materials used in bonded panels shall meet the
shall be made prior to surface preparation or on the panel
requirements of the contract or specified drawings. All mate-
following completion of the bonding operation. The faying
rials shall be stored and handled in such manner so as to
surfaces of aluminum parts to be bonded shall be prepared as
provide protection against degrading environments and me-
designated in 8.2.2. All prepared aluminum for bonded panels
chanical damage.
shall be stored to prevent contamination of the bonding
surface. Prepared parts that are not bonded within 72 h after
7.2 Aluminum:
cleaning shall be reprocessed as designated in 8.2. The faying
7.2.1 Facings—The facings shall be aluminum alloy con-
surfaces of plastic and foam and wood parts to be bonded shall
forming to Specification B209 and shall be certified as com-
be as designated in 8.5 and 8.6 respectively. All material
plyingwiththealloy,temper,andthicknessrequirementsofthe
prepared for bonding shall be handled with clean cotton gloves
shelter specification. Facings shall be free of corrosion, exces-
to prevent contamination of surfaces prior to bonding.
sive oil canning (snap-buckling), dents, gouges, or other
8.1.1 Adhesive Application—Adhesive shall be applied uni-
defects that may adversely affect the structural integrity of the
formly on all faying surfaces of the parts being bonded. It shall
bonded panel. Manufacturers’ certification of reports of tests
be applied in such a manner and in sufficient quantity to fill all
for mechanical properties and chemical composition shall be
voids between faying surfaces and to ensure a continuous bond
available or included with each shipment, or both.
between p
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1801 − 15 E1801 − 21
Standard Practice for
Adhesive Bonding of Aluminum Facings in Foam and Beam
Type Shelters
This standard is issued under the fixed designation E1801; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This practice covers the materials, processes, and quality controls to be used in the manufacture of adhesive-bonded,
aluminum-faced, foam core sandwich panels for tactical shelters.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B209 Specification for Aluminum and Aluminum-Alloy Sheet and Plate
E631 Terminology of Building Constructions
E1730 Specification for Rigid Foam for Use in Structural Sandwich Panel Cores
E1749 Terminology Relating to Rigid Wall Relocatable Shelters
E1793 Practice for Preparation of Aluminum Alloy for Bonding in Foam and Beam Type Transportable Shelters
E1794 Specification for Adhesive for Bonding Foam Cored Sandwich Panels (200°F Elevated Humidity Service), Type II Panels
E1800 Specification for Adhesive for Bonding Foam Cored Sandwich Panels (160°F Elevated Humidity Service), Type I Panels
2.2 Federal Standard:
QQ-A-250/11 Alumium Alloy 6061–T6 Plate and Sheet
3. Terminology
3.1 Definitions—See Terminologies E631 and E1749 for definitions of general terms used in this practice.
This practice is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.53 on Materials and
Processes for Durable Rigidwall Relocatable Structures.
Current edition approved May 1, 2015Feb. 1, 2021. Published August 2015February 2021. Originally approved in 1996. Last previous edition approved in 20092015 as
E1801 – 09.E1801 – 15. DOI: 10.1520/E1801-15.10.1520/E1801-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Available from DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1801 − 21
3.1 Definitions:
3.1.1 For definitions of general terms related to building construction used in this practice, refer to Terminology E631, and for
general terms related to rigid wall relocatable shelters, refer to Terminology E1749.
4. Significance and Use
4.1 The formation of reproducible, durable adhesive bonds in structural units requires great care in the performance of the steps
in the bonding process. Experience has shown that adhesive bonding carried out in accordance with this practice produces
reproducible adhesive bonds. This practice is applicable to both the Type 1, 160°F (71°C),160 °F (71 °C), and Type 2, 200°F
(93°C),200 °F (93 °C), elevated humidity service type of foam and beam shelter.
5. Facilities
5.1 Panel Assembly Layup Area—The panel assembly layup area shall be a ventilated area maintained at a minimum temperature
of 68°F (20°C).68 °F (20 °C). The area shall be free of oils, grease, silicone, lint, or other contaminants detrimental to the
production of adhesive bonds.
5.2 Post-Curing Rooms—The post-curing rooms shall provide a uniform temperature distribution over all panels and over all
portions of the panels exposed for post-curing. The total temperature range shall be no more than 25°F (14°C).25 °F (14 °C).
6. Apparatus
6.1 Pressure Equipment—Pressure equipment for bonding of shelter panels shall be large enough to permit the bonding of a
complete panel in one step. The manufacturer shall provide calibration and test data demonstrating that the temperature on the two
facings of the press platens during bonding will be equal and uniform within 65°F (63°C)65 °F (63 °C) of the indicated
temperature. The platens shall be flat to within 0.003 in./ft (0.08 mm/305 mm) and shall be smooth having a maximum surface
roughness of 125 rms. The pressure equipment shall be equipped with temperature and pressure recorders and controls that
accurately control heat-up, pressure applied, and dwell time.
6.2 Calibrations, Temperature and Pressure Requirements, and Controls—Gages shall be calibrated every six months by an
accredited independent laboratory or by the panel manufacturer if approved by the purchaser. All calibrations shall be traceable
to the National Institute of Standards and Technology. The latest calibration certificate shall be attached to the equipment near each
gage. Thermocouples placed at each corner and at the center of each facing shall be used to demonstrate the uniformity of the
temperature. A permanent record of the pressure, time, and temperature during bonding shall be maintained.
6.3 Calibration of Testing Equipment—Calibration of the required testing equipment shall be done in accordance with the
equipment manufacturer’s instructions. All calibrations of test equipment required by this practice shall be traceable to the National
Institute of Standards and Technology.
7. Materials
7.1 The materials used in bonded panels shall meet the requirements of the contract or specified drawings. All materials shall be
stored and handled in such manner so as to provide protection against degrading environments and mechanical damage.
7.2 Aluminum:
7.2.1 Facings—The facings shall be aluminum alloy conforming to Specification B209 and shall be certified as complying with
the alloy, temper, and thickness requirements of the shelter specification. Facings shall be free of corrosion, excessive oil canning
(snap-buckling), dents, gouges, or other defects that may adversely affect the structural integrity of the bonded panel.
Manufacturers’ certification of reports of tests for mechanical properties and chemical composition shall be available or included
with each shipment, or both.
7.2.2 Preparation of Aluminum-Alloy Parts for Bonding:
7.2.2.1 Type 1, 160°F (71°C),160 °F (71 °C), Elevated Humidity Service Shelters—The aluminum-alloy parts used in the
manufacture of Type 1 foam and beam panels shall be prepared for bonding in accordance with Practice E1793 and Specification
E1801 − 21
E1800. The surface resistance of 6061-T6 aluminum alloy (QQ-A-250/11) test coupons cleaned by the same process, shall be no
more than 100 microhms when measured under a nominal electrode force of 600600 psi 6 25 psi (4.14(4.14 MPa 6 1.70 MPa)
and a current of 10 610 amperes 6 0.2 amperes. Five coupons shall be tested during each 4 h of cleaning operations.
7.2.2.2 Type 2, 200°F (93°C),200 °F (93 °C), Elevated Humidity Service Shelters—The aluminum-alloy parts used in the
manufacture of Type 2 foam and beam panels shall be prepared for bonding in accordance with Practice E1793 and Specification
E1794. The surface resistance of the cleaned parts, or test coupons of the same alloy and cleaned by the same process, shall be
no more than 100 microhms when measured under a nominal electrode force of 600600 psi 6 25 psi (4.14(4.14 MPa 6 1.7 MPa)
and a current of 10 6 0.210 amperes 6 0.2 amperes. Five coupons shall be tested during each 4 h of cleaning operations.
7.3 Foam Core—The foam core material shall be as specified in the shelter specification and shall meet the requirements of
Specification E1730. Manufacturers’Manufacturers’ certification or reports of tests for conformance to this specification shall be
available or included with each shipment, or both.
7.4 Adhesives—The adhesive shall conform to Specification E1800 for Type 1 shelters or Specification E1794 for Type 2 shelters.
The adhesive shall be stored and used in accordance with the manufacturer’s recommendations. Manufacturers’ certification or
reports of tests for conformance to this specification shall be available or included with each shipment, or both.
7.5 Preparation of Nonmetallic Parts Prior to Bonding—If necessary, all plastic, wood, and foam parts used in the construction
of these shelters shall be prepared for bonding prior to the application of the adhesive. Parts with gouges, broken edges, splits or
cracks, or other defects shall not be used.
8. Bonding and Curing
8.1 Preparation of Materials Bonding—All cutting, trimming, and sizing of aluminum, plastic, and wood parts shall be made prior
to surface preparation or on the panel following completion of the bonding operation. The faying surfaces of aluminum parts to
be bonded shall be p
...