Downloaded from http://www.everyspec.

com

NOTE: MIL-A-83377B has been redesignated as a handbook, and is to be used for

guidance purposes only. For administrative expediency, the only physical change from
MIL-A-83377B is this cover page. However, this document is no longer to be cited as a
requirement. If cited as a requirement, contractors may disregard the requirements of this
document and interpret its contents only as guidance.

NOT MEASURMENT SENSITIVE

MIL-HDBK-83377
31 December 1997
SUPERSEDING
MIL-A-83377B
6 October 1978

DEPARTMENT OF DEFENSE

HANDBOOK

ADHESIVE BONDING (STRUCTURAL) FOR AEROSPACE AND

OTHER SYSTEMS, REQUIREMENTS FOR

THIS HANDBOOK IS FOR GUIDANCE ONLY

DO NOT CITE THIS DOCUMENT AS A REQUIREMENT

AMSC N/A FSC 8040

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
 Downloaded from http://www.everyspec.com

MIL-A-83377B
6 October 1978
SUPERSEDING
MIL-A-83377A(USAF)
24 June 1975

MILITARY SPECIFICATION
ADHESIVE BONDING (STRUCTURAL) FOR AEROSPACE AND
OTHER SYSTEMS, REQUIREMENTS FOR

This specification is approved for use by all Departments and Agencies of the
Department of Defense.

1. SCOPE

1.1 Scope.
This document covers requirements applicable to structural adhesive bonding of
metal, composites, and core material in any combination.

1.2 Classification.
The classification of adhesive bonded structures specified herein shall be as
follows:
Type I - Primary structure (see 6.3.4)
Type II - Secondary structure (see 6.3.4)

2. APPLICABLE DOCUMENTS

2.1 Issues of documents.

The following documents of the issue in effect on date of invitation for bids or
request for proposal, form a part of this specification to the extent specified herein.
SPECIFICATIONS
FEDERAL
UU-P-268 Paper, Kraft, Wrapping
Beneficial comments (recommendations, additions, deletions) and any pertinent
data which may be of use in improving this document should be addressed to the
Air Force Materials Laboratory, MXA, WPAFB, Ohio 45433 by using the self-
addressed Standardization Document Improvement Proposal (DD Form 1426)
appearing at the end of this document or by letter.

FSC 8040

1
 Downloaded from http://www.everyspec.com

MIL-A-83377B

MILITARY
MIL-C-5541 Chemical Conversion Coatings on Aluminum and
Aluminum Alloys
MIL-I-6870 Inspection Program Requirements,
Nondestructive: For Aircraft and Missile Materials
and Parts
MIL-A-8625 Anodic Coatings, for Aluminum and Aluminum
Alloys
MIL-A-83376 Adhesive Bonded Metal Faced Sandwich
Structures, Acceptance Criteria
(Copies of specifications, standards, drawings, and publications required by
contractors in connection with specific procurement functions should be obtained
from the procuring activity or as directed by the contracting officer.)

2.2 Other publications.

The following documents form a part of this specification to the extent specified
herein. Unless otherwise indicated, the issue in effect on date of invitation for bids
or request for proposal shall apply.

AMERICAN SOCIETY FOR TESTING AND MA TERI ALS (ASTM)

ASTM D2674 Analysis of Sulfochromate Etch Solution Used in Surface
Preparation of Aluminum
ASTM D2919 Determining Durability of Adhesive Joints Stressed in
Shear by Tension Loading
ASTM D3433 Fracture Strength in Cleavage of Adhesives in Bonded
Joints
(Application for copies should be addressed to the American Society for Testing
and Materials, 1916 Race Street, Philadelphia, PA 19103.)

SOCIETY OF AUTOMOTIVE ENGINEERS (SAE)

ARP 1524 Surface Preparation and Priming of Aluminum Alloy Parts
for High Durability Structural Adhesive Bonding,
Phosphoric Acid Anodizing
(Application for copies should be addressed to the Society of Automotive
Engineers, Incorporated, 400 Commonwealth Drive, Warrendale, PA 15096.)

2
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3. REQUIREMENTS

3.1 Policy.
This document specifies two basic documentary requirements for contractors (and
their subcontractors) manufacturing adhesively bonded parts and assemblies for
aerospace use. These requirements are to provide a process specification and an
engineering report. The process specification is required to insure that the control
of quality and uniformity during fabrication of bonded assemblies is recorded. The
engineering report is to provide the Government procuring activity a record
showing which of the important technical areas necessary for the production of
dependable quality bonded aerospace components have been considered by the
contractor. (See 6.3). The process specification and engineering report shall be
prepared and submitted to the contracting agency at the commencement of the
production of material to which it applies and, thereafter, during the course of
production for use by authorized Government and industry inspectors in the facility
of the contractor, his subcontractors, or his vendors.

3.1.1 Process specification.

A detailed description of the manufacturing and fabricating process and methods
of control of manufacturing variables in the form of a titled, numbered, and dated
process specification shall be prepared by the prime contractor. The specific
requirements, processes, inspection methods, and precautions specified shall be
included and completely described.

3.1.2 Engineering report.

Unless the information is already included in the structural report, an engineering
report shall be prepared describing all tests used as a basis for preparation of the
process specification and the detail drawing requirements of adhesive bonded
components. The engineering report shall contain a discussion of the effects on
the strength of the adhesively bonded assemblies of various environment factors
that may be encountered by the bonded parts during their operational life. With
existing contracts where materials and processes have been well established, a
limited engineering report may suffice. Following is a partial checklist of factors
whose effects shall be considered, as applicable:

(a) humidity
(b) salt spray or other deleterious atmosphere
(c) vibration

(d) cyclic temperature and temperature extremes,

(e) outgassing due to space vacuum

(f) x-ray, gamma-ray, UV, IR, electrical, and other energies

(g) toxicity of adhesive materials originally, and after exposure to

environmental extremes

3
 Downloaded from http://www.everyspec.com

MIL-A-83377B

(h) thermal and chemical sterilization

(i) stress durability, and

(j) fatigue and fracture.

3.1.3 Approval of documents.

Prior to commencement of production, the process specification and engineering
report shall be submitted to the procuring activity for approval. Subsequent
changes, such as to shop processes, which affect the validity of the approved
document shall be made when considered necessary. However, the procuring
activity shall be contacted immediately concerning the changes. Further, formal
documentation of the changes shall be submitted to the procuring activity within 30
days of the initiation of the changes.

3.2 General requirements.

3.2.1
3.2.1 The prime contractor shall assure adherence by his subcontractors to the
provisions of this document. In the event of bonded assembly failures, the prime
contractor shall be responsible for assisting in the resolution of any subcontractor
problems.
3.2.2
3.2.2 The adhesives and primers used and their application procedures shall
provide for the specified durability, integrity and minimum strength for the bonded
parts during the proposed life of the bonded assembly and throughout exposure to
all environmental factors that could reasonably be encountered during the
anticipated life of the assembly.

3.2.3
3.2.3 All materials used in the adhesive bonding process shall conform to
applicable Government or other specifications as stipulated by the procuring
activity. Justification shall be presented in the contractor's engineering report when
Government or Government approved material specifications cannot be used.
Where Government or Government approved specifications are not completely
adequate, contractor's material specifications shall specify, whenever possible,
that the materials conform to the Government or Government approved document
plus any additional requirements necessary.

3.2.4 For aluminum (other than core), bonding to a chemical film coating such as
MIL-C-5541 or to any surface cladding which is anodic to the base metal is not
recommended. The contractor's engineering report shall completely substantiate
the need to employ this type of bonding and shall document the reliability of the
bond.

3.2.5 Techniques or precautions required for proper storage and use of adhesives
and associated materials, such as bondline thickness control, control of adhesive
application, special temperature or humidity controls necessary during handling of
adhesive and method of adhesive and primer application, which may be applicable
to the particular adhesive or to the conditions of fabrication being employed shall
be included in the process specification.

4
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3.2.4 Stress durability for materials and process selection.

The selection of adhesive, primer and other bonding process procedures shall be
based on the materials and processes which exhibit good stress durability in
environments as determined by methods such as ASTM D2919, similar stressed
lap shear tests, or ASTM D3433. The primary mode of failure in the environmental
tests documented in the engineering report shall be cohesive within the adhesive
rather than adhesive failure between the substrate and the primer or between the
primer and adhesive. Cyclic stressed durability is preferred whenever possible.
Environments should include the highest temperatures and humidities to be seen
by the bonded assembly.

3.2.5 Corrosion proofing of bond joint.

All aluminum bond joint areas that can at any time be exposed to humidity,
moisture, salt spray, or other corrosive environments shall be protected against
delamination and corrosion by either phosphoric acid anodize per ARP 1524 or
chromic acid anodize per MIL-A-8625 plus corrosion inhibiting primer (CIP) or a
treatment determined to be equal to these in stress durability studies. Sealing or
overcoating of the bond joint by sealants or coatings shall not be deemed sufficient
protection to eliminate this requirement. All processes shall include corrosion
inhibiting primer (CIAP), unless non-use is adequately substantiated by the
contractor's engineering report.
NOTE: Phosphoric acid anodizing is the preferred method for all bonding of 250°F
and lower temperature curing adhesives, and also for higher curing adhesives
wherever compatibility has been established.

3.2.6 Protection of bonded joints.

Complete details of the materials and procedures to be used in the protection of
bonded joints shall be included in the process specification. Bonded joints, such as
at the exposed edges of sandwich components, access doors, and windows shall
be protected against exposure to or entrance of liquids (water, fuel, oil, etc.) into
the core of the sandwich. Bonded sandwich assemblies shall be tested for
adequacy of sealing by leak tests specified in 4.2.3.4. All permanent fasteners
penetrating bond joints shall be wet installed with sealant. Instructions for this
operation shall be included in the contractor's process specification.
NOTE: Instructions for the drilling of holes for attachments through bonded joints in
a manner that prevents bond line delamination and the installation of fasteners
with sealant shall be included in the contractor's process specification.

5
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3.2.7 Bonding personnel.

Structural bonding operations shall only be performed by qualified personnel.
Qualified personnel are those who have demonstrated the knowledge and practical
proficiency to indicate they possess the skills and job knowledge necessary to
ensure acceptable workmanship. A list of qualified prime or subcontractor bonding
personnel shall be issued indicating qualification and level of proficiency, and
requalification date. This list shall be available for review by Government
personnel.

3.3 Processing.

3.3.1 Bonding.

3.3.1.1 Process and assembly area.

All application of adhesive and primers shall be conducted in a controlled area as
specified in the contractor's process specification. If priming and cleaning areas
are not immediately adjacent to each other, parts shall be moved into a controlled
area within one hour maximum. Areas through which unprotected treated details
are transported shall not contain dust, oily vapors, aerosols, or contaminants
deleterious to bonding.

3.3.1.2 Controlled area.

The controlled area shall be maintained under positive pressure differential at all
times by a continuously operating air handling system. The following conditions
apply unless otherwise documented by engineering report:

(a) air filtration - regular maintenance of filters

(b) no eating or smoking in the area

(c) maintain records of controlled area conditions

(d) vehicles permitted in the controlled area must be nonpolluting in

operation, such as electrically or hand propelled

(e) no process or operation which produces uncontrolled spray, dust, fumes,

or particulate matter is permitted in the controlled area.

3.3.1.3 Temperature/relative humidity in controlled areas.

ranging from 65 to 85°F (18.3 to 29.4°C) and a maximum relative humidity of 60
percent shall be the controlled conditions.

3.3.2 Equipment.

3.3.2.1 Presses, bond forms, autoclaves, ovens and pressure equipment.

The temperature and pressure requirements for bonding operations (including
primer curing), and details of procedures to be followed shall be included in the
process specification. All pressure and temperature equipment and gauges shall
be tested and calibrated on a scheduled basis. Thermal qualification shall be
certified only by qualified measurement personnel, not production personnel.

6
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3.3.2.2 Tool qualification.

Each bonding tool shall be qualified prior to production by the verification film
technique specified in 3.3.3.1, or by the destructive evaluation of the first bonded
assembly, or by proof loading or other suitable means approved by the contracting
agency. Succeeding parts will be selected for requalification based on the results
of the Quality Control tests in 4.2.1, 4.2.2, and 4.2.3.1. Each bonding tool shall be
subject to contractor engineering review to determine if requalification is necessary
if any dimensional or thermal control changes are made to the tool. This includes
changing the thickness or method of placement of bleeder cloth, shims, caul
plates, etc., that could be reasonably expected to affect the thermal or dimensional
characteristics of the tool.

3.3.3 Detail parts.

3.3.3.1 Prefitting of parts.

The detail parts of all structural assemblies shall be prefitted to assure that the
detail parts fit together properly. This prefitting requirement may be waived where
the assembly involves simple parts. Detail parts shall be free of burrs, waves, and
other surface imperfections. All prefitted detail parts shall be kept together
throughout subsequent cleaning operations or these parts shall be marked with an
identification number to allow assembly in proper sequence. Assemblies shall have
the fit of their detail parts verified by suitable means, such as dry prefit, commercial
"verification" film or the use of 0.0015 Mylar (or equal) on each side of an adhesive
film while the assembly is subjected to production processing, including regular
heat and pressure cycles in accordance with a sampling plan to be established by
the contractor and defined in the Manufacturing Process Specification. The
verification film must be submitted to Quality Control inspectors for approval prior
to final bonding of the assembly. Verification film records shall be retained for a
minimum of six months following assembly, fabrication, and acceptance.
Verification records, including the verification film or, a photograph of the
verification film, shall be retained and available for a minimum period of five years
for later examination in case of bonded assembly failure or other problems.

3.3.3.2 Control of parts.

Completed assemblies shall be so marked that they can be tracked and identified.
Detail parts shall be controlled from the point of bonding prefit until they become
an integral part of the assembly.

7
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3.3.4 Cleaning of materials for bonding.

3.3.4.1
3.3.4.1 The process specification shall specify the procedure for treatment of
faying surfaces of parts to be bonded, and precautions to be taken to eliminate
contamination of treated surfaces awaiting application of adhesive or primer. The
time that treated parts may remain uncoated shall also be specified, and
substantiated by tests described in the contractor's engineering report. Silicone
based cutting and forming fluids shall not be used when processing detail parts for
bonded assemblies. Parts shall not be allowed to dry between any chemical
operations.

3.3.4.2 Control of cleaning solutions.

Suitable process control tests, such as the wedge test or -65°F peel test, (using
sensitive adhesives such as 250°F curing modified epoxies), shall be performed to
assure that each assembly or cleaning line load has been satisfactorily surface
treated. All surface preparation solutions in use shall be tested at least weekly and
maintained at the proper concentration as specified in the process specification.
After addition of make-up material or complete change of solution, cleaning
solutions shall be retested and found acceptable before production use. (For
analysis procedures reference ASTM D2674.)

3.3.5 Adhesive primer application.

Adhesive primer shall be applied to aluminum detail parts to be bonded within 96
hours after cleaning. Steel parts must be primed within 4 hours after cleaning.
Titanium parts must be primed within 16 hours of cleaning. Parts shall have been
protected by paper or other wrapping or stored in the controlled area from time of
cleaning through priming. Parts awaiting priming or adhesion application shall be
handled in such a manner that no physical contact is made to any surface that will
be bonded by touching the surface with hands, white gloves, paper, or other
means. Surface rubbing, even with paper, must be avoided. The requirements to
be followed for primer application shall be described in the process specification.
The contractor's engineering report shall include data proving the procedure is
adequate for the intended use. If compressed air is used, it shall be filtered free of
oil and moisture at the application station by means of a replaceable cartridge type
filter capable of satisfactory removal of oil and moisture. (NOTE: All shop air used
on cleaned assemblies shall be similarly treated.) After primer application and
drying, the coated parts shall be kept dry and free from dirt, grease, oil, wax or
other contamination. Primed surfaces shall not be touched with bare hands or any
equipment with a contamination potential.

3.3.6 Handling of cleaned and primed parts.

Cleaned, or cleaned and primed parts shall not be handled with bare hands nor
shall any contamination result from contact with supporting fixtures or mechanical
handling equipment. One or two pairs of clean, white, lint-free gloves shall be worn
by all persons handling cleaned parts, cleaned and primed parts or

8
 Downloaded from http://www.everyspec.com

MIL-A-83377B

adhesive films. After parts have been cleaned, dried, and primed, they shall be
wrapped in clean neutral non-sulfur containing protective paper conforming to UU-
P-268 or covered with clean plastic film, determined to have no contamination
potential, as soon as they cool to room temperature, unless primed parts are
stored in the controlled area and bonded within the time restrictions of the process
specification. Low density polyethylene is not acceptable.

3.3.7 Control of adhesives and prepreg.

Adhesive to be used in production bonding of parts shall be sampled and tested in
accordance with the process specification for the adhesive involved. The faying
surfaces of the test specimens shall be treated by the same method and materials
as are used on production parts. All bonding materials stored in cold storage shall
be allowed to warm to a temperature precluding moisture condensation before
they are unwrapped. Adhesive shall not be released for production unless:

(a) Receiving Inspection and control tests have been conducted and found to
be acceptable in accordance with the applicable process specification.

(b) It has been in proper storage since Receiving Inspection or Quality

Control testing.

Temperature and method of storage after release for production shall be as

determined for each material involved and shall be outlined in the contractor's
process specification.

3.3.8 Adhesive application.

3.3.8.1
3.3.8.1 The exact procedures to be followed, and equipment to be used in the
application of the adhesive to the specific materials to be bonded shall be
described in the process specification. The contractor's engineering report shall
include data proving the procedure is adequate for the intended use. After
application of the adhesive, the coated parts shall be kept dry and free from dirt,
grease, oil, wax, or other foreign material and shall not be handled with the bare
hands. The length of time adhesive coated parts are allowed to stand before
bonding shall not exceed the open assembly life of the adhesive and shall be
specified in the process specification. Precautions to be taken to eliminate physical
contamination of the adhesive coatings shall also be specified therein.

9
 Downloaded from http://www.everyspec.com

MIL-A-83377B

3.3.8.2
3.3.8.2 Primed detail parts shall be bonded within the time period specified in the
process specification. After application, film adhesives shall not be wrinkled or
distorted. Mixing of two-part adhesives shall preferably be accomplished by
appropriate automatic apparatus designed to minimize air entrapment. Mix ratio
shall be verified by a Quality Control representative on a periodic basis. Adhesive
mixing shall be accomplished only by qualified personnel. If hand or open bucket
mixing is used, measuring methods and equipment shall be prescribed by the
contractor's process specification. All two-part, hand mixed adhesives, whenever
possible, shall be degassed under vacuum before use. The vacuum shall be
applied and released for the minimum time necessary to remove air bubbles, but
not so long as to withdraw significant amounts of volatile curing agents, etc.

3.3.9 Assembly of parts.

The process specification shall describe procedures to be used in the assembly of

parts. Care shall be taken in assembling parts in the curing fixture or jig to assure
that the adhesive is not disturbed and that excessive residual stresses are
avoided. Use of aerosol type release agents is prohibited in controlled areas or
other areas as specified in the process specification. Only non-contaminating films,
tapes, etc., shall be used for release purposes. Shims and caul plates shall be
used as much as necessary to ensure that every adhesive bondline has adequate
support and pressure application. Clean-up solvent shall be prevented from
entering or contacting the bondline.

3.3.10 Curing of adhesive.

The process specification shall contain detailed curing procedures. However, heat
curing cycles shall be chosen so that, as a result of processing through the
maximum number of cycles that may occur during fabrication, there will be no
reduction of mechanical or corrosion resistant properties of the materials being
bonded to values below the minimum values of the applicable specification or
drawing. All assemblies shall be cured as soon as possible after adhesive
application within the open time specified in the process specification. Assemblies
shall be reviewed by the contractor's engineers to determine the need for placing
in a bond form or holding fixture while being held for bonding.

3.3.11 Multiple stage bonding.

Bonded assemblies which are to be recleaned for multiple stage bonding shall be
processed according to the applicable process specification, using recommended
procedures to protect original bond joints and crevices from cleaning solution
entrapment. If bonded subassemblies are to be bonded again into final
assemblies, a description of precautions to be taken to assure that subsequent
surface preparation and bonding operations have no detrimental effects on the
initially bonded parts shall be included in the

10
 Downloaded from http://www.everyspec.com

MIL-A-83377B

process specification. Documentation of the fact that subsequent operations do not

affect the bond integrity of the original subassembly shall be presented in the
contractor's engineering report. This reporting shall include test data to
substantiate that subsequent cure cycle exposures do not degrade the bond
strength of any previous bonds or materials. Sufficient shims and caul plates shall
be used to assure that proper pressure and alignment are maintained during
secondary bonding operations.

3.3.12 Rework or repair.

Provision for rework or repair of defective parts shall be stated in the process
specification and shall be subject to approval, on demand, by the prime contractor
or procuring activity.

4. QUALITY ASSURANCE PROVISIONS

4.1 Responsibility for inspection.

Unless otherwise specified in the contract, the contractor is responsible for the
performance of all inspection requirements as specified herein. Except as
otherwise specified in the contract, the contractor may use his own or any other
facilities suitable for the performance of the inspection requirements specified
herein, unless disapproved by the Government. The Government reserves the
right to perform any of the inspections set forth in the specification where such
inspections are deemed necessary to assure supplies and services conform to
prescribed requirements.

4.2 Quality control tests.

4.2.1 Quality control test panels.

Destructive quality control test panels for manufacturing process control shall be
required on a frequency as specified in the contractor's process specification.

4.2.2 Preparation of extensions, coupons, or standard specimens.

Production bonded parts, shall incorporate, where possible, extensions or coupons
that may be cut from the parts after bonding and will be representative of the
bonds obtained in the parts proper. Where extensions cannot be incorporated in
the parts, standard test panel specimens shall be fabricated. These shall be
cleaned and bonded at the same time, with the same adhesive, in the same
equipment, and under the same conditions as the assembly they represent. The
procedures for their incorporation or fabrication shall be included in the process
specification. The number of extensions, coupons, or specimens shall be specified
by the contractor in the process specification.

4.2.2.1 Test method.

Destructive quality control tests shall be made of the adhesive bonds in the
extensions, coupons, or standard test panel specimens prepared as described in
paragraph 4.2.2. The test procedures to be used and the acceptance criteria shall
be specified in the process specification. If the test tab per assembly method is
used, daily lap shear and/or peel tests, or crack extension specimens shall be
included in the quality control system as a control of the cleaning process.

11
 Downloaded from http://www.everyspec.com

MIL-A-83377B

4.2.3 Tests on complete assemblies.

4.2.3.1 Destructive inspection.

Destructive inspection shall be made on parts selected in accordance with 4.2.1 to
insure proper fabrication of parts through the production run. Any evidence of
improper cure, adhesion, misalignment, etc., shall be immediately corrected by
making necessary adjustment in the cure cyles or in tooling. (NOTE: Above
sampling and testing procedures apply to bonded parts that do not use formal
bonding tool or fixture.)
4.2.3.2
4.2.3.2 For short production runs of items (10 or less) destructive evaluation
testing as outlined above may be waived providing 100 percent bond line
verification is made prior to bonding of each assembly, and 100 percent
nondestructive testing (NDT) inspection of each part is made as specified in
4.2.3.3.

4.2.3.3 Nondestructive testing.

4.2.3.3.1
4.2.3.3.1 The contractor shall submit a complete NDT process specification when
required by MIL-I-6870 to evaluate the quality of adhesively bonded structures.
The NDT process specification shall be submitted for approval by the Government
prior to bonded assembly production. The contractor shall specify the type and
size of defects that are acceptable. The size of the allowable defects must be
correlated with the capability of the NDT method to be used, realizing that NDT
methods and instrumentation have different capabilities for the testing of adhesive
bonded structures. The application of these different NDT methods is limited by
material types and design configuration. For aluminum honeycomb sandwich, the
allowables of MIL-A-83376 may be used, if determined by the contractor to be
acceptable minimums for the particular application.

4.2.3.3.2 Nondestructive testing of adhesive bonded structures shall only be

performed by qualified NDT personnel. Qualified NDT personnel are those who
have demonstrated by passing written and practical proficiency tests that they
possess the skills and job knowledge necessary to insure an acceptable level of
performance in the nondestructive testing of adhesively bonded structures as
required by MIL-I-6870. A list of qualified NDT personnel shall be maintained and
made available to Government personnel for on-site review. Personnel
qualifications shall be reviewed at least annually.

12
 Downloaded from http://www.everyspec.com

MIL-A-83377B

4.2.3.3.3
4.2.3.3.3 Unless otherwise agreed upon between the contractor and the procuring
activity, bonds shall be inspected on the following minimum frequency as specified
in Table I.

Table I. NDT frequency.

Bond Condition Assembly Frequency Area Frequency
Type I 1/ Types: I, II
Type II
Metal-to-metal Each assy AQL 2/
Face-to-core Each assy AQL 6" grid minimum
Sandwich Const.

1/ Contractor to establish inspection plan based on mutually acceptable AQL.

2/ This information to be included in the NDT process specification as per 4.2.3.3.1

4.2.3.4 Leak testing of sandwich assemblies.

4.2.3.4.1
4.2.3.4.1 The first unit of each assembly shall be leak tested. The subsequent
frequency shall be every Type I assembly and each fifth Type II assembly. (NOTE:
Waiving of this requirement may be possible in specific instances to be
negotiated.)
4.2.3.4.2 Assemblies shall be leak tested by submerging into 170°F ± 10°F water
for one minute minimum, 2 minutes maximum, and observing for air bubbles along
bond joints indicating leaks. Immediately upon removal of assemblies from water,
the excess water on panel surface shall be removed by wiping with absorbent
material. The assemblies shall not be submerged into water under more than a six
foot head of water. An alternate method of leak testing may be utilized when
approved by the procuring agency.

4.2.3.4.3 Bonded assemblies, sealed as specified in 3.2.8 shall be leak tested in

accordance with 4.2.3.4.1 and 4.2.3.4.2. Leaking assemblies shall be dried,
resealed and retested in the same manner. If the assembly leaks on second test, it
shall be referred for Material Review Board action.

13
 Downloaded from http://www.everyspec.com

MIL-A-83377B

4.2.4 The materials and processes covered by the contractor's process

specification, the articles fabricated thereby, and the tests made thereon shall be
subjected to the inspection and supervision of authorized Government inspectors.
Reports of tests performed shall be furnished to the authorized inspectors.

5. PACKAGING
This section is not applicable to this specification.

6. NOTES
6.1 Intended use.
It is intended that the requirements of this document be mandatory requirements
for use by contractors to assure the reliability of adhesive bonded structural
components used in aerospace and other systems. Structural adhesive bonding is
a critical process that must be properly controlled to achieve the benefits in lighter
weight, lower cost, and fatigue improvement not obtainable in other types of
construction.

6.2 Joint design.

Bonded joint design shall be carefully considered for all bonded assemblies. The
bonded joint, where possible, shall make maximum effective use of the adhesive's
properties. Peel and cleavage forces shall be designed out of all joints to the
greatest extent possible.

6.3 Definitions.

6.3.1 Prime contractor.

A prime contractor is a contractor fabricating items under direct contract with the
Government. (Whenever the term contractor the appears in this specification, it will
be construed to be the prime contractor.)

6.3.2 Subcontractor.
A subcontractor is a fabricator supplying items or components to a prime
contractor.

6.3.3 Process specification.

Whenever the term process specification appears in this specification, it will be
construed to be the contractor process specification prepared in accordance with
this specification.

6.3.4 Classification.
The classification of adhesive bonded structures specified in this specification shall
be of the following types:
Type I - Components which are fracture or fatigue critical as defined
in MIL-I-6870, components the single failure of which would
cause significant danger to operating personnel or would
result in an operational penalty. This includes loss of major
components, loss of control, unintentional release, inability

14
 Downloaded from http://www.everyspec.com

MIL-A-83377B

to release armament stores, or failure of weapon installation

components.
Type II - All components not classified as Type I.

6.3.4.1 Structural classification.

The structural classification, Type I or Type II shall be specified on the engineering
drawing. All structures shall be considered Type I unless otherwise specified on
the drawing.

Custodians: Preparing Activity:

Air Force - 11 Air Force - 11
Navy - AS
Army - MR
Project No. 8040 - 0385
User Activities:
Navy - AS, OS

15
 Downloaded from http://www.everyspec.com

INST17UCTION5. In s continuing effort to make our ttubrdiitio. f!ocumen!s L-u-. the DoD pnxtdes this form for w in
submitting comments md sussafiaru for impromnenb. All us- of ndfitav sfamfardiuti.n documenu am imited to provide
m?sutioM. ‘fM8 f- WY ~ de~h4 fold- dons tie lima indimtd twed don th. hw edge (00 NOT STAPLE), and
uaited. ISI block 6, be u K-U” u Pmible ●bout rmrticuhr problem areas such u -wdhs wI@! rewi=d ir.temretstion, .8s
km rigid, mstricti?e, 100M, ambwtu, or mJ incommtible, and si~eproposedwc.rdins cban.yeawbtcbwoutdatlwtate tbe
~blmnm. Enterinblock6 Uly remarkInotrehtedtoa sP@rI pamgmpb of thedOcumnlt.u tdock7 n ratedout,m
acknodeds.mmlt Wfn b - to You ~- so *Y. ~ ~t You ~- tit Y- CamLaenla mmreceimdudu’abekk
I cmddcred.

NOTE: ‘IMu fom mw riot be w?6 to .q.at copies at document% nor to request wairers, dmhtions, or cfmifkation uc
I
m=kfi=tion -c@-IM~ 011 -rat -IIhti. CaIIIIWnti bubmftt=d on fbh form do not mistitufe or imrdy ●utborizmion
fo mire my portion of the refemnccd document(s) or to amend con fxutual mquirmnenti.

(Fold dmu OIL. IOU)

tFold do., thh 11”. )

DEPARTMENT OF TtiE AIR FORCE

111111 F]

UNITED STATES

OFFICIAL BUSINESS
PENALTV FOR PR,VATE “SE S300 BUSINESS REPL~sHMWc,
FIRST CLASS PEllMIT NO. 132=

POSTAGE WILL BE PAID BY THE DEPARTMENT OF THE AIR FORCE

ASD/SNESS
Wright-Patterson AFB, OH 45433
 Downloaded from http://www.everyspec.com

STANDARDIZATION DOCUMENT IMPROVEMENT PROPOSAL

(See Instructions - Side)
Reverse

>OCUMENT NUMBEn 2. DOCUMENT TITLE

NAME 0P SUBMITTING oRGANIZATION 4, TYPE OF ORGAN! ZATION (Nub MI.)

VENDOR
•1

❑ USER

h00FIE6S (S-.1. C1tY. Stat=. ZJPCodc)

D MANUFACTURER

❑ O,”,rl,spdti):

PROBLEM AREAS

a P..w.wh Nurnti. UUt W.,dl”g:

b, R-mnmor.d=cl Wo-dl”s:

c. R.mm/R. !io..l. for %cw!m...titn:n:

I I
REMARKS
I

I
I I
I
I
I

,. NAME OF SUB MI TTE13 fLat, Fir.1, MI) - o.ti...l b. wORK TELEPHONE NUMOER(l.el”de Am.
Codcl -Oc.r(o..l

9AAIL3NG AL) ORES5 (S,-.,, City. S,.,., ZfP Cod.) - 0.,!0”.1 a. DATE OF SUBMISSION (YYMMDD)

I
I DO20)!%
1426 PREVIOUS EOITION IS OBSOLETE