B-F501_REV_D__DOC_14_approved_OEMimages.pdf

2017-10-24

PCO LETTER REQUEST

A-10 TLPS

Legacy VI 10/24/2017

Contract/Delivery Order Number: FA8202-15-D-0001

Program Manager: Edie Messina

Letter Number: A10-CDM-0001-E-17-0075

Date of Letter: 10/18/2017

CDRL Number: A129

Document Title:

A-10 Process Specification Adhesives, Epoxy - General Purpose, Process for

Document/ Drawing Number: B-F501 Rev D

NOT APPROVED (See comment below)

X APPROVED

APPROVED Subject to inclusion of attached comments

OTHER (please identify below)

Notes:

Program Manager Signature and Date:

X

CAGE 77751 B-F501

Revision D

17 August 2017

Data contained on this sheet is subject to the restrictions on the title page of this document.

ii

REVISION DESCRIPTION

REV. DATE DESCRIPTION

– 09/14/1973 Original.

A 12/12/1975 Incorporated amendments and respecified raw material properties.

B 11/01/1978 Added alternate Type II adhesives.

C 04/03/1997 Incorporated amendments B(1) through B(5), with the following exception:

Omitted various notes allowing use of deleted materials through depletion; since the A-10 is no longer in production and Fairchild Republic is no longer in business, notes are no longer relevant.

Created Table of Contents up to third-place decimals and List of Tables.

Reason for change: To enable easier location of appropriate sections and tables.

Added Foreword describing the review of this specification for toxins, pollutants and other hazardous materials, and establishing user responsibility for following all laws and regulations involving their use.

Reason for change: To comply with requirements of contract.

Revised introduction to Section 2.0, and deleted revision letters/numbers from documents.

Reason for change: To reassign governance to the revision of applicable documents in effect at the time of a particular contract; this is consistent with other A-10 Program specifications.

In Section 2.0, designated applicable documents sections as 2.1,

2.2 and 2.3; had been unnumbered.

Reason for change: To enable quick reference in Table of Contents.

In Section 2.1, Federal Specifications, deleted TT-M-261, Methyl Ethyl Ketone; TT-T-548, Toluene, Technical; and O-T-620, 1,1,1- Trichloroethane, Technical (Methyl Chloroform).

Reason for change: To eliminate the use of ozone depleting substances (ODSs) and reduce the use of hazardous air pollutants (HAPs).

In Section 2.1, Federal Specifications, replaced solvents with TT-N- 95 Ty. II, Naphtha/Methyl Propyl Ketone (MPK) blend 50/50 ± 2% by weight; and TT-I-735 Gr. A, Isopropyl Alcohol.

Reason for change: New solvents are low in HAPs or HAP-free.

iii

C 04/03/1997 (Continued)

In Section 2.1, Federal Specifications, added O-S-890, Sulfuric Acid, Concentrated; and O-S-595, Sodium Dichromate C.P.

Reason for change: Were added to Section 3.2.c in Amendment B1, but were omitted from Section 2.1 in that Amendment.

In Section 2.2, Military Specifications, and Section 3.4.2.4, changed MIL-P-23377 to Rev. G.

Reason for change: Rev. G specifies the use of high-solids primer, which is lower in volatile organic compounds (VOCs) and HAPs.

Updated Materials, Section 3.2, as follows:

Part a, Epoxy Adhesives:

EC2216: Added Scotch-Weld designation and A/B to reflect two-part system; added full address and proper division for 3M Co. EA9330: Provided proper corporate name; added full address. EA934NA: Provided proper corporate name; added full address. Epibond 1543: Updated corporate identity of manufacturer: was Furane/M & T Chemicals; is Ciba-Geigy Corporation, Furane Aerospace Products; added full address.

Part b, Solvents:

Deleted TT-M-261, Methyl Ethyl Ketone; TT-T-548, Toluene, Technical; and Denatured Alcohol; restricted Naphtha, Aliphatic, TT-N-95, to Type II only; replaced solvents with Naphtha/Methyl Propyl Ketone (MPK) blend 50/50 ± 2% by weight; and TT-I-735 Gr. A, Isopropyl Alcohol; to list sources of supply of new solvents.

Part c, Miscellaneous Materials:

Added Rymplecloth #301, an approved wiper for solvent use, and sources for its supply; deleted trichloroethylene and carbon tetrachloride soluble content test requirements.

Part d, Abrasives:

No changes.

Reason for change: To reduce use of HAPs; to reflect present manufacturers of materials and provide full addresses for ease of contact.

Revised Tables I, II and III; named Table III; was unnamed.

Reason for change: To improve clarity and enable quick reference in List of Tables.

iv

C 04/03/1997 (Continued)

Revised Section 3.4.2.1, as follows:

In Part a, replaced trichloroethane with denatured alcohol, isopropyl alcohol or acetone.

Reason for change: New solvents are non-ozone depleting and lower in HAPs.

Revised Section 3.4.2.2, as follows:

In Part a, replaced methyl ethyl ketone with naphtha or naphtha/MPK blend; added use of Rymplecloth #301.

Reason for change: New solvents are lower in HAPs;

Rymplecloth #301 is an approved wiper for solvents.

Revised Section 3.4.2.4, as follows:

In Part b, replaced methyl ethyl ketone and toluene with naphtha, naphtha/MPK blend or isopropyl alcohol.

Reason for change: New solvents are lower in HAPs.

Revised Section 3.4.2.5, as follows:

In Part a, replaced methyl ethyl ketone and toluene with naphtha, naphtha/MPK blend or isopropyl alcohol.

Reason for change: New solvents are lower in HAPs.

Revised Section 3.4.2.6, as follows:

Replaced methyl ethyl ketone and toluene with naphtha, naphtha/MPK blend or isopropyl alcohol.

Reason for change: New solvents are lower in HAPs.

Revised thermoplastic surface preparation table in Section 3.5.

Reason for change: To improve clarity.

Revised Section 4.1.1.a.1, as follows:

Deleted reference to FRC (Fairchild Republic Company).

Reason for change: Fairchild Republic Company is no longer in business.

REV. CHANGES REASON FOR CHANGE APPROVED

D

08/17/17 Reformatted. Incorporated Attachment 1 of Rev. C into the Foreword.

Specification requirement. M. Kassinger

In Section 2.0, updated documents;

changed references throughout to agree with Section 2.0 changes.

To agree with latest specifications.

v

(Cont’d.)

Deleted Epibond 1543 throughout document.

Material is no longer available.

Added Epibond 300 throughout document.

To provide alternate Type II adhesive.

In Para. 3.1 b, changed “white cotton gloves” to “gloves per Section 3.2, Item c.”

To permit the use of gloves other than cotton.

In Para. 3.1 e, changed “untreated metal parts” to “metal parts not treated in accordance with Section 3.4.2.”

Clarity.

Revised Table I. To agree with material suppliers’ designations and properties.

Revised Table II. To agree with material and properties.

In Para. 3.2 b, updated solvent suppliers and part numbers; deleted MPK/naphtha blend; callouts throughout document modified to reflect these changes. Added Note directing that aliphatic naphtha must pass acrylic crazing test in TT-N-95, Sec. 4.3.7.

To reflect current information and availability of solvents. To prevent crazing of windshields and other acrylic materials.

In Para. 3.2 c, added cleaning cloths per AMS 3819, listing Rymplecloth as an example; deleted NOTE;

deleted cheesecloth, gauze and new or laundered rags; added nitrile gloves; added BONDERITE C-AK

4215 AERO.

Approved wipers;

requirements within NOTE are covered in AMS 3819;

no longer required; to provide more glove choices; was omitted in earlier revisions.

In Para. 3.2 d, added “aluminum oxide” to description of abrasive paper.

To specify appropriate paper type.

In Para. 3.3.1 e, changed reference to 3.3.2, Item d (was 3.2.2, Item d).

To correct typo.

vi

(Cont’d.)

In Para. 3.3.2 c, changed end of last sentence to “high viscosity adhesives (e.g., Epibond 300).”; was “the extremely high viscosity adhesive.”

Clarity.

In Para. 3.4.1 c, changed “white knitted gloves” to “gloves per Section 3.2, Item c.”

gloves other than knitted.

In Para. 3.4.2.1, bolded heading. Consistency.

In Para. 3.4.2.1 b., changed T4215 to BONDERITE C-AK 4215 AERO.

Current material designation, per the supplier.

In Para. 3.4.2.1, below Item c, rewrote acid cleaning solution preparation instructions.

Clarity; per Air Force direction.

In Para. 3.4.2.1 e, in NOTE, changed “white cotton gloves” to “gloves per Section 3.2, Item c.”

gloves other than cotton.

In Para. 3.4.2.2 a, including Steps 1 and 2, changed “cheesecloth, gauze, or Rymplecloth 301” to “cloths per Paragraph 3.2, Item b.”

To reflect use of cloths per

AMS 3819.

In Para. 3.4.2.2 b, added “aluminum oxide” to description of abrasive paper.

To specify appropriate paper type.

In Para. 3.4.2.3 and Sec. 3.5, numbered previously unnumbered tables as Table III and Table IV, respectively. Renumbered previous Table III as Table V.

To improve navigation within document and allow visibility of tables within the List of Tables.

In Para. 3.4.2.3 a, added isopropyl alcohol and methyl propyl ketone.

To include all appropriate solvents.

In Table III, under Acetals, Method 2, in first sentence, after “solution” changed to: “as noted in Paragraph 3.4.2.1, Item c for 1–2 seconds at room temperature.”

Clarity.

vii

(Cont’d.)

In Table III, under Polyolefins, in second sentence, replaced “per S- F501” with: “as noted in Paragraph 3.4.2.1, Item c.”

Clarity.

In Para. 3.4.2.5, changed grit to “220” (was “250”); added “aluminum oxide” to description of abrasive paper.

To correct typo; to specify appropriate paper type.

In Para. 3.4.2.6, changed “hardenable” to “hardened.”

To correct typo.

Revised Table IV. To agree with material and cure cycles.

Added Para. 4.1.4. To define retest requirements, which had been undefined.

Revised Table V. To agree with material suppliers’ storage lives and storage temperatures.

In Para. 4.2.1 a, changed “shelf life” to “storage life.”

Consistency of terminology.

In Para. 6.1.1, updated name and address of SPI: The Plastics Industry Trade Association (formerly the Society of the Plastics Industry).

Organization name changed; organization moved; previous address was no longer valid.

Relocated Attachment 1 of Rev. C to Foreword.

More-appropriate location for this item.

viii

TABLE OF CONTENTS

REVISION DESCRIPTION .............................................................................................. ii

LIST OF TABLES ........................................................................................................ ix

FOREWORD ................................................................................................................... x

1.0 SCOPE

1.1 Types and Use

2.0 APPLICABLE DOCUMENTS

2.1 Federal Specifications

2.2 Military Specifications

2.3 A-10 Program Specifications

2.4 Industry Specifications

3.0 REQUIREMENTS

3.1 General Requirements

3.2 Materials

3.3 Mixing of Adhesives

3.4 Preparation for Bonding

3.5 Assembly of Parts and Cure

3.6 Process Control Requirements

4.0 QUALITY ASSURANCE PROVISIONS

4.1 Receiving Inspection and Storage of Materials

4.2 Production Control Requirements

5.0 PREPARATION FOR DELIVERY

6.0 NOTES

6.1 Safety Precautions

ix

LIST OF TABLES

Table I: Raw Material Properties

Table II: Adhesive Properties

Table III: Preparation of Thermoplastic Surfaces

Table IV: Adhesive Cure Cycles

Table V: Storage Life and Retest Requirements x

FOREWORD

This specification has been reviewed for EPA 17 toxic chemicals, SARA 313-listed pollutants, as well as ozone depleting substances. All ozone depleting substances have been removed.

Hazardous air pollutants and toxic materials have been eliminated or minimized to comply with the Air Force Pollution Prevention Program, AFI 32-7080. A reasonable effort has been made to eliminate rather than minimize pollutants and to use environmentally acceptable substitutes. Certain substitutions, however, have not been made due to their potential unknown deleterious effects on the A-10 weapon system.

Government and other industry specifications called out in this specification have been reviewed. (See Applicable Documents section of this specification for documents reviewed.)

Ozone depleting substances and hazardous materials have been identified and reported on in accordance with Contract F04606-96-D-0021 CET SM-ALC/LAF 96-A10-A1-9 D.O. 0016.

It must be understood that the materials, methods, applications and processes can contain toxic and hazardous materials. It is the responsibility of the user to ensure safe and proper use in accordance with all applicable OSHA, EPA, Federal, state and local regulations.

The intent of this report is to explain why chemicals known as the EPA 17 are still required by this specification and the effort that was made to find a substitute. Contract F04606-96- D-0021, Delivery Order 0016, did not include provisions or require a test program(s) to replace these materials.

Material EPA 17 F04606-96-D-0021-0016 Effort Made to Find Substitute

MMM-A-132 Certain Constituents of Jet Fuel

Jet fuel replacement was not considered within the scope of this Delivery Order.

O-S-595 Sodium Dichromate, Chromates

Chromates are added to cleaning solutions to prevent attack during etching and also to add additional enhanced bonding characteristics to the surface. Non-chromated alternatives must be tested for A-10 use, which goes beyond the scope of this Delivery Order.

MIL-P-23377G Chromates Alternative primers are available and supplied by Spraylat and Deft Chemical. However, they are not qualified to the original A-10 design requirements.

Chromates are used to inhibit corrosion. These alternative primers are currently under laboratory and field test programs being conducted by the Navy and Air Force, as well as Northrop Grumman. Since they are still under study, it was not prudent to change away from chromated inhibitors at this time.

xi

Material EPA 17 F04606-96-D-0021-0016 Effort Made to Find Substitute

MIL-C-83286 None.

Reason: MIL-C- 83286 is not used in specification; only referenced.

Not applicable.

MIL-C-85285 None.

Reason: MIL-C- 85285 is not used in specification; only referenced.

Not applicable.

The above materials could not be replaced with alternate environmentally acceptable materials due to the lack of test data or qualified environmentally acceptable alternative materials. Aerospace industry practice requires that only fully qualified materials be used to assure high reliability or safety of flight considerations.

1.0 SCOPE

This specification establishes the materials and process requirements for two-part epoxy based adhesive systems. These adhesive systems may be used to bond various materials such as metals, glass fabric laminates, thermoplastics, etc. for non-structural and secondary bonding.

1.1 Types and Use

Type I –65 to 180°F Type II –65 to 250°F

2.0 APPLICABLE DOCUMENTS

The following documents of the issue in effect on the effective date of contract shall form part of this specification. In the event of conflict between the contractual documents referenced herein and the requirements of this specification, the contractual documents referenced herein shall govern.

2.1 Federal Specifications

A-A-55828 Sulfuric Acid, Technical

A-A-58054 Abrasive Mats, Non-Woven, Non-Metallic A-A-59123 Sodium Dichromate Dihydrate MMM-A-132 Adhesives, Heat Resistant, Airframe Structural, Metal to Metal TT-N-95 Naphtha, Aliphatic TT-I-735 Isopropyl Alcohol

2.2 Military Specifications

MIL-PRF-23377 Primer Coatings: Epoxy, High-Solids MIL-PRF-85285 Coating: Polyurethane, Aircraft and Support Equipment

2.3 A-10 Program Specifications

P-T301 Surface Treatment of Fluorocarbon Materials S-F501 Bonding, Structural Adhesive-Sandwich/Laminates, Aluminum

Alloy S-F502 Process Specification for the Fabrication of 250°F Curing

Epoxy Resin Composite Laminate and Honeycomb Sandwich Parts

2.4 Industry Specifications

AMS 3819 Cloths, Cleaning, for Aircraft Primary and Secondary Structural Surfaces

ASTM D329 Acetone, Technical

3.0 REQUIREMENTS

3.1 General Requirements

a. Untreated titanium shall not be bonded per this document.

b. Cleaned parts shall be handled by personnel wearing clean gloves per Section 3.2, Item c.

c. When solvent wiping, keep solvent out of cracks and crevices or other confined areas. Do not dry parts using compressed air.

d. Manufacturing shall adhere to safety precautions noted in Para. 6.1.

e. Unless otherwise specified, metal parts not treated in accordance with Section 3.4.2 shall not be bonded in accordance with this specification.

3.2 Materials

a. Epoxy Adhesives

Epoxy adhesives as listed below shall be certified to the requirements of Table I and Table II.

The vendor shall furnish a test report on each batch of materials, reporting lap shear values at 75°F, and “T” peel values at 75°F, where applicable.

Type I Scotch-Weld EC2216 B/A Gray 3M Adhesive Systems

Industrial Tape and Specialties Division 3M Center, Building 220-7E-01 St. Paul, MN 55144-1000

EA9330 Henkel Aerospace 2850 Willow Pass Road, PO Box 312 Pittsburg, CA 94565-0031

Type II EA934NA Henkel Aerospace

2850 Willow Pass Road, PO Box 312 Pittsburg, CA 94565-0031

Epibond 300 Huntsman Corporation 10003 Woodloch Forest Drive The Woodlands, TX 77380

Table I: Raw Material Properties

Property Type I Type II

EC2216

B/A Gray EA9330 EA934NA Epibond 300

Color Part A Part B

Gray White

Cream Amber

Amber

Off-White

Viscosity, poises/75°F

400–800

750–1500

600–1500

7–17

3500–9000

10–30

8000–12,000

300–550

Mix Ratio, parts by weight

Work Life at 75°F, 100g mass Minutes

25–35

Table II: Adhesive Properties

Property Type I Type II

EC2216

B/A Gray EA9330 EA934NA Epibond 300

Lap Shear, psi –65°F –67°F 75°F 180°F 200°F 250°F 300°F

4000 (min.)

4500 (min.)

850 (min.)

“T” Peel

75°F/PIW

Cure 7 days/75°F or

2 hrs./150°F

7 days/75°F

2 hrs./180°F

1 hr./200°F

1 hr./165°F

NOTES:

1. Preparation and testing of lap shear and “T” peel shall be in accordance with

MMM-A-132.

2. PIW = pounds/inch width.

b. Solvents

Denatured Alcohol Any source Acetone, Technical, ASTM D329 Any source Isopropyl Alcohol, TT-I-735 Gr. A Any source Aliphatic Naphtha, TT-N-95 Ty. II NOTE: Each batch of aliphatic naphtha shall successfully pass the acrylic crazing test outlined in TT-N-95, Section 4.3.7.

Shell Chemical Company PO Box 2463 Houston, TX 77252-2463 Part No. ShellSol W HT

MACH-DYNAMICS

494 Main Street Susquehanna, PA 18847-7979

Methyl Propyl Ketone (MPK), Technical Grade [90.0% by wt. min. MPK/10.0% by

wt. max. MIBK]

Eastman Chemical Company PO Box 431 Kingsport, TN 376620431

Methyl Propyl Ketone (MPK), Ultra High Purity [99.5% by wt. min. MPK/0.5% by wt.

max. MIBK]

Eastman Chemical Company PO Box 431 Kingsport, TN 37662-0431

c. Miscellaneous Materials

BONDERITE C-AK 4215 AERO Henkel Corporation USA Madison Heights, MI 48071

Sulfuric Acid, Technical, A-A-55828 Any source Sodium Dichromate Dihydrate, A-A-59123 Any source Gloves, white cotton Any source Thin mill gloves (nitrile), Ansell #92-600

ANE92-600-6.5-Small ANE92-600-7.5-Medium ANE92-600-8.5-Large ANE92-600-9.5-Extra Large

Suggested source of supply:

Airgas Safety 2355 Workman Mill Road City of Industry, CA 90601-1459 or equivalent

Nitrile exam glove, powder-free, textured, purple, 55082-55084

Kimberly-Clark Professional 1400 Holcomb Bridge Road Roswell, GA 30076-2190 or equivalent

Cloths, cleaning, per AMS 3819 Class 1, Grade A, Form 1 e.g., Rymplecloth #301, 100% purified cotton

Any source suggested sources:

1) American Fiber and Finishing, Inc.

225 North Depot Street Albemarle, NC 28001-3914

2) John R. Lyman Company 60 Depot Street Chicopee, MA 01013-1251

d. Abrasives

Wet or dry aluminum oxide abrasive paper, 220-grit or finer

Any source

Abrasive pad, A-A-58054 Type I Class 1 or 2 Grade A

Any source

3.3 Mixing of Adhesives

3.3.1 Equipment

a. Any suitable mixing or blending equipment that will produce a smooth, workable mixture free from lumps and entrapped air may be used. Small amounts of material may be hand mixed.

b. Containers for the blended adhesive shall be of glass, metal, Teflon, polyethylene, or polyethylene-lined paper cardboard. Do not use waxed or porous paper containers.

c. Use only clean, dry containers, mixing or dispensing equipment. Clean all equipment with solvents recommended by the applicable equipment manufacturer. Clean at least daily as well as during any lengthy interruption of application, on completion of the job, changing of adhesives, or use of different types or batches of the same adhesive. Dry all equipment before use.

d. Containers and equipment used for silicone adhesives shall not be used for non-silicone adhesives.

e. Equipment for dispensing or weighing components of adhesives shall be sufficiently accurate or sensitive to meet the requirements of Section 3.3.2, Item d.

f. The work area shall not experience temperatures below 65°F or above 100°F.

3.3.2 Preparation of Adhesives

a. When the adhesive has been stored below 65°F, remove the unopened container from storage and condition to room temperature, 65°F minimum, prior to mixing.

b. When the individual components of a multiple-component adhesive have been under refrigeration, remove the unopened containers from storage and condition them to room temperature, 65°F minimum, prior to mixing and weighing out of the desired quantities preparatory to blending.

c. Addition or omission of ingredients or deviation from the specified mixing or blending procedure is not allowed. Do not thin adhesives unless specifically permitted under the detailed application procedure for that adhesive in this specification. When air is entrapped in adhesive due to the mixing or blending, allow sufficient time for it to be released. Deaeration is recommended for high viscosity adhesives (e.g., Epibond 300).

NOTE: Mixing is defined as the act of stirring or shaking a separate component to form a uniform dispersion of the ingredients of the components. Blending is defined as the bringing of separate components intimately together to form a homogeneous blend.

d. Dispense by machine or weigh the individual components of multiple-component adhesives to the proportions specified herein, ± 2.5%, unless otherwise specified.

e. Use the original containers of clean metal, glass, polyethylene, or Teflon for all mixing or blending of adhesives or primers. When mixing or blending is to be accomplished by hand, only clean stirrers, such as a metal spatula, may be used. Do not use metal containers showing any rust on the inside.

f. Do not use undated or outdated materials.

g. Place each unit of blended adhesive in a suitable container and mark to indicate:

1. Manufacturer’s designation.

2. Manufacturer’s batch number.

3. Date and time of blending.

4. Expiration date and time.

5. Mixer’s identification.

h. High temperature and humidity or large amount of adhesive will shorten the pot life. Low temperature or small amount of adhesive will extend the pot life. If possible, blend the desired amount of adhesive only immediately prior to bonding.

i. When adhesive is repackaged into smaller units, the new containers shall meet the requirements of Section 3.3.1, Items b and c. Labels on the new containers shall include the same information as on the original container labels.

j. Before transferring the contents of larger containers to smaller ones, mix the adhesive until it is homogeneous.

3.4 Preparation for Bonding

3.4.1 Preparation of Faying Surfaces

a. All surfaces to be joined during the bonding operation shall be prefitted so that only very light pressure (1–2 psi) is required to give continuous contact all over the surfaces to be bonded.

b. The key requirement for the production of high strength adhesive bonds is the cleanliness of the surfaces to which the adhesive must adhere. All foreign materials such as oils, greases, waxes, or powders must be removed prior to the application of the adhesive.

c. Application of adhesives should follow immediately after the preparation of faying surfaces.

Alternately, the prepared surfaces should be protected by bagging in a thermoplastic material. Extreme care must be taken to keep all dust and foreign materials off the bonding surfaces during subsequent operations. Avoid touching the cleaned surfaces. Use clean gloves per Section 3.2, Item c. when handling parts.

d. When bonding adjacent to decorative areas, mask around the edges of decorative surfaces to prevent adhesive from squeezing onto those areas. Strip off masking materials as soon as the adhesive begins to set, pulling it slowly, close and parallel to the edge of bonding.

e. On non-decorative parts, clean a slightly larger area than that to be bonded and/or to be contacted by the adhesive.

f. Unless otherwise specified, solvent clean all bondable surfaces as noted below.

1. Apply solvent to surface by dispensing from squirt- or squeeze-type bottles. Do not dip the wiper in the solvent container.

2. Use a clean wiper and rub the surface until the major portion of soil is removed.

Scrub with a soft bristle brush if necessary to remove difficult soils.

3. Exchange soiled wiper for clean one frequently.

4. Repeat above operations until the wiper shows no soil.

5. Dry the parts by wiping the remaining solvent using a clean, dry wiper. Do not allow the puddles or droplets of solvent to evaporate to dryness.

6. Protect the parts from dust, fingerprints, or other contamination.

3.4.2 Cleaning Procedures

3.4.2.1 Calendered, Extruded, or Molded Rubber Parts, Except Silicone Rubber—See Section 3.4.2.8 for silicone rubber cleaning procedure.

a. Solvent wipe all surfaces with denatured alcohol, isopropyl alcohol or acetone.

b. Immerse in BONDERITE C-AK 4215 AERO alkaline cleaner for 10 min. at 150°F to 170°F.

c. Immerse in acid cleaning solution (see below) for 10 to 12 min. at 100°F to 120°F. Rinse in clean running water for 2 to 3 min. Check for water break-free surface; if not obtained, repeat step c.

To prepare one (1) liter of acid cleaning solution:

Dissolve 28 to 67 grams of sodium dichromate in 700 ml of distilled water. Add 288 to 310 grams of concentrated sulfuric acid and mix well. Add additional distilled water to fill to one (1) liter.

d. Air dry at room temperature or oven dry at temperatures up to 140°F.

e. Package parts individually in polyethylene bags and seal. Mark bags with part number and date of processing.

NOTE: Cleaned parts shall be handled only while wearing clean gloves per Section 3.2, Item c to avoid contamination.

3.4.2.2 Thermosetting Plastics

a. Solvent wipe area to be bonded with aliphatic naphtha per TT-N-95 Ty. II or methyl propyl ketone (MPK) and wipe off with clean, dry cloths per Paragraph 3.2, Item c as follows:

1. Saturate cloths per Paragraph 3.2, Item c and wipe surface.

2. While surface is still wet with solvent, wipe dry using dry cloths per Paragraph 3.2, Item c. Wipe in one direction only using one wiper per side so removed contamination is not redeposited.

b. Abrade the surface using 220-grit, or finer, wet or dry aluminum oxide abrasive paper, or abrasive pad.

c. Repeat Step a.

d. Where a peel ply is used on a surface to be bonded, Steps a through c shall be eliminated if peel ply is not removed until the part is ready to be bonded. If the peel ply has been removed or surface contamination has occurred, then Steps a through c shall be followed.

3.4.2.3 Thermoplastic Surfaces

a. When using solvents to clean thermoplastics, use aliphatic naphtha, TT-N-95, Type II;

isopropyl alcohol; or denatured alcohol. Do not use methyl ethyl ketone, methyl isobutyl ketone, acetone, methyl propyl ketone, or toluene to clean thermoplastics.

b. Preparation of surfaces of thermoplastics prior to the adhesive bonding is summarized in Table III (using solvents as specified in Item a).

Table III: Preparation of Thermoplastic Surfaces

Plastic Adherend Cleaning Procedure

Acetals

Method 1: Wipe with solvent. Sand. Wipe with a clean, dry cloth. Repeat solvent wipe and dry.

Method 2: Wipe with solvent and treat with sulfuric acid-dichromate solution as noted in Paragraph 3.4.2.1, Item c for 1–2 seconds at room temperature. Remove, wash with water and allow to air dry.

Acrylics Vinyls

Wipe with solvent. Sand, unless used for optical or decorative application. Repeat solvent wipe and dry when sanded.

Cellulosics Polyamides Polycarbonate Polystyrenes Polysulfone

Wipe with solvent. Sand. Wipe with a clean, dry cloth.

Repeat solvent wipe and dry.

Polytetrafluoroethylene (PTFE, Teflon)

Unetched Teflon must be surface treated per P-T301 prior to bonding.

Polyolefins (Polythethylene, Polypropylene)

Wipe with solvent and treat with solution of sulfuric acid-dichromate as noted in Paragraph 3.4.2.1, Item c for 1 hour at room temperature. Remove and rinse thoroughly under running tap water for at least 3 minutes and dry. Do not wipe the surface during or after treatment.

3.4.2.4 MIL-PRF-23377 Primed Surfaces

a. Primer shall be dried for one of the following periods prior to solvent wiping, if it has been freshly applied:

24 hours at 75°F, or 45-minute solvent flash-off plus 6 hours at 150°F, or 45-minute solvent flash-off plus 1/2 hour at 200°F.

NOTE: Parts fabricated per S-F501 and S-F502 shall not be exposed to temperatures above 150°F.

b. Surfaces shall be prepared by solvent wiping using naphtha, MPK, or isopropyl alcohol.

3.4.2.5 MIL-PRF-85285 Polyurethane Surfaces

Abrade surfaces using 220-grit or finer aluminum oxide sandpaper and solvent wipe using naphtha, MPK, or isopropyl alcohol.

3.4.2.6 Stainless Steel

Stainless steel (type 300 series) or precipitation hardened stainless steels, whose surfaces have been passivated, shall be wiped with a clean wiper saturated with naphtha, MPK, or isopropyl alcohol.

3.4.2.7 Paper, Felt, Cork, and Leather

Surface preparation is not generally required. Remove dust and other obvious surface contaminants with a clean cloth.

3.4.2.8 Silicone Rubber Surfaces

a. When solvent cleaning silicone rubber, use denatured alcohol, isopropyl alcohol, or acetone.

b. Do not soak. Prolonged exposure to these solvents will induce swelling.

3.5 Assembly of Parts and Cure

The following application procedures shall govern the use of the type of adhesive called out on the applicable drawing.

a. All personnel involved in the application and/or inspection of adhesives shall be trained as to their knowledge of and proficiency in the requirements, materials, and processes of this specification.

b. The mixed adhesive shall be applied to one of the bondable surfaces and shall be 5 to 20 mils thick.

c. A fillet may be provided along the bond line edges if the excess adhesive does not present an appearance problem and does not interfere with the fit of subsequent mating parts.

d. Bonding pressure shall be uniformly distributed over the area being bonded during cure and shall be maintained as constant (non-varying) as possible. The recommended bonding pressure is 5 psi minimum.

e. Unless otherwise specified, do not apply and cure adhesives at a temperature below 65°F.

f. Adhesive shall be cured using one of the cure cycles listed in Table IV.

Table IV: Adhesive Cure Cycles

Type I 1/ Type II

EC2216

B/A Gray EA9330 EA934NA Epibond 300

2 hrs./150°F

2 hrs./180°F

1 hr./200°F

1 hr./165°F 1/ Assemblies bonded using Type I adhesive shall be cooled to below 180°F before release of pressure.

NOTES:

1. All bonded assemblies shall not be exposed to environments greater than that noted in Para. 1.1.

2. Curing for 24 hours at 75°F will yield 70% of lap shear strength shown in Table II.

3.6 Process Control Requirements

3.6.1 When specified on Engineering drawing and for critical applications, lap shear process control specimens shall be fabricated with the production assembly. The lap shear specimens shall be of the same composition and finish as the production part being bonded, and use the same adhesive mix and cure schedule. Three specimens shall be prepared.

Ultimate values shall be noted on the Engineering drawings.

4.0 QUALITY ASSURANCE PROVISIONS

4.1 Receiving Inspection and Storage of Materials

4.1.1 Identification

a. Each individual container of adhesive shall be durably and legibly marked with the following information:

1. B-F501, revision letter; type of adhesive; and component designation.

2. Manufacturer’s name and material designation.

3. Purchase order number.

4. Quantity.

5. Manufacturer’s batch number.

6. Date of manufacture.

7. Recommended storage temperature.

8. Storage life expiration date.

4.1.2 Testing of received adhesive will be at the option of Quality Assurance. Quality Assurance will perform tests of any or all of the requirements noted in Tables I and II.

4.1.3 Storage life, conditions and retest requirements shall be in accordance with Table V.

Retesting after expiration of storage life is at the option of Quality Assurance.

4.1.4 After the initial adhesive storage life has been met, the adhesive may be reevaluated for an additional 3-month storage life. The adhesive must meet Table I requirements for viscosity and work life and Table II requirements for room temperature lap shear strength.

Test three (3) lap shear specimens and perform one (1) viscosity and work life test.

Table V: Storage Life and Retest Requirements

Manufacturer Material

Designation

Storage Life Storage Temperature, °F Vendor Guarantee Maximum Before Retest

EC2216

B/A Gray 2 years 2 years 60–80

EA9330 1 year 1 year Below 75 EA934NA 1 year 1 year Below 40

Epibond 300 6 months 6 months Below 77

4.2 Production Control Requirements

4.2.1 Materials

a. Repackaged materials shall be labeled with the same information as were the original containers. Expiration date based on storage life information in Para. 4.1.1 shall be included.

b. Retesting shall be subject to the following limitations:

1. Routine retesting need be performed only at expiration of the maximum storage periods noted in Table V. Earlier retesting, as in response to a shop request or for materials stored at uncontrolled temperatures, shall be at Quality Control’s option.

2. All retesting and storage life extension shall be at the discretion of Quality Control and shall take into consideration the quantity and cost of material involved and past experience with the particular adhesive.

c. Undated or over-age material shall not be issued or used, but shall be scrapped.

d. All materials covered by this specification shall be used on the basis of first in, first out.

4.2.2 Processes and Part Inspection

a. Quality Control Production Inspection shall pay particular attention to the following items in the process:

1. The requirements of Sec. 3.0.

2. That the adhesives used are those required by the applicable drawing.

b. Acceptable parts shall have a continuous bond along the edges of the mating surfaces.

There shall be a visible bead of extruded adhesive if the excess adhesive does not present an appearance problem and does not interfere with the fit of subsequent mating parts.

c. Reject parts with loose edges or corners or with delaminations in the adjacent adherend.

d. Reject parts with detectable voids, blistering, cracks, or unfilled areas in bond.

e. Adhesive bonds shall not be tested by peeling back the adherends except when authorized as a process control test.

5.0 PREPARATION FOR DELIVERY

Not Applicable

6.0 NOTES

6.1 Safety Precautions

Many of the chemicals employed herein are flammable, toxic, or both. Consult the appropriate fire, industrial hygiene and safety organizations on facilities, equipment, ventilation and other requirements for safe operation.

6.1.1 Epoxy adhesives may cause skin and eye irritation. Avoid contact with skin and eyes. If contact occurs, wash with soap and water; flush eyes immediately with plenty of water. This product carries SPI Classification 2, according to “Guides for Classifying and Labeling Epoxy Products According to Their Hazardous Potentialities,” prepared and published by SPI: The Plastics Industry Trade Association (formerly the Society of the Plastics Industry), 1425 K Street NW, Suite 500, Washington, DC 20005-3500; www.plasticsindustry.org; (202) 974- 5200.

http://www.plasticsindustry.org/