giv srm 51-21-00 2re(1) alodine 1200 (a) initial makeup - fill acid resistant plastic container...

CHEMICAL TREATMENT OF MATERIALS — REPAIRS

NOTICE: THIS REPAIR PAGEBLOCK (PAGES 201-2XX) IS FAA APPROVED AND IS INTENDED FOROPERATOR USE IN ACHIEVING REPAIR INSTALLATIONS ACCEPTABLE TO THEIR LOCALAPPROVAL AUTHORITY.

SPECIFIC REPAIR INSTALLATION CLASSIFICATION (MAJOR OR MINOR) AND SPECIFICREQUIREMENTS FOR DATA FROM THIS PAGEBLOCK (PAGES 201-2XX) WILL BEDICTATED BY THE NATURE OF THE STRUCTURE BEING REPAIRED.

IT IS THE RESPONSIBILITY OF THE OPERATOR TO ENSURE THAT THE REPAIRINSTALLATION, DOCUMENTATION AND ANY REQUIRED ENGINEERING ACTION(EVALUATION, DESIGN, ANALYSIS, ETC.) MEET THE REGULATIONS OF THE FAA OROTHER GOVERNING REGULATORY AGENCY, AS APPLICABLE, BEFORE RETURNINGTHE AIRCRAFT TO SERVICE.

1. Chromate Conversion Coating of Aluminum Alloys

A. General

(1) Scope

This specification describes the process and manual application of the requirements for thechromate conversion coating to aluminum alloy. Coatings applied per this specification are usedas a corrosion preventative film, either painted or unpainted.

(a) Grades

This specification defines the Manual Application, Grade B, for conversion coatings asshall be used in repair of aircraft structure. For information on immersion techniques,contact Gulfstream Technical Operations.

Grades - Application

• Grade B - Manual application (brush and wipe)• Grade C - Immersion application (not covered in this specification)

(b) Applicability

Conversion coatings applied per this document will meet the requirements of MIL-C-5541,Class 1A and 3.

(2) Applicable Documents

The following documents shall form a part of this specification to the extent specified. See Table201.

B. Requirements

(1) Materials - Only the following materials are required:

(a) Chemical Conversion Materials

• Alodine 600; Parker Amchem Products, Inc. See Individual Process and FinishCodes, 51-20-00, General Finish 213

• Alodine 1200; Parker Amchem Products, Inc. See Individual Process and FinishCodes, 51-20-00, General Finish 76

STRUCTURAL REPAIR MANUAL

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• Alodine Toner 22; Parker Amchem Products, Inc.

NOTE: When required, contact Gulfstream Technical Operations to establish initial makeup and solution test procedures.

(b) Miscellaneous Materials

• Hand wiping solvent: Methyl Ethyl Ketone (MEK) per ASTM D 740, Methyl PropylKetone (MPK) per GAS115K or acetone per ASTM D 329

• Nitric Acid per O-N-350, 38° Be• 350 Masking tape; 3M Co• Abrasive paper / cloth, 320 grit or finer, aluminum oxide or silicon carbide

(2) General Requirements

(a) Material - Coatings shall be formed from materials which have been accepted for listing asClass 1A or 3 compounds on the Qualified Products List of MIL-C-81706.

(b) Basic metal - Surfaces to be coated shall be free from defects which would be detrimentalto the function or appearance of the coating.

(c) Sequence - Chromate conversion coatings shall be applied after all basic metal heattreatments and mechanical operations of the separate article have been completed.These include perforating, machining, brazing and welding.

(d) Other metals - The following metals in assembly with aluminum to be conversion coateddo not require masking: Chromium and nickel plate, corrosion resistant steels, titaniumand nickel or cobalt base alloys. All other metals shall be masked. Electrical wiring andloose fabrics shall not be exposed to any solution required for this process. No assembliesshall be conversion coated which have the potential for retention of residual conversioncoating material.

(e) Preparation - Parts or assemblies to be coated shall first be cleaned per Step 1.C.(1) toremove all oil, oxides and other contaminants until water break free surfaces are observedafter rinsing at room temperature. Handle cleaned parts so as to avoid any subsequentcontamination.

(f) Appearance - Conversion coatings shall be substantially free from powdery or loose filmareas and shall be free from breaks, scratches, or other defects.

NOTE: Coatings may vary greatly in color shade, intensity, or uniformity (from lightiridescent gold to brown) and such variations shall not be a sole cause forrejection.

(g) Grade B Coating - Grade B coating methods are applicable to surfaces of large or partiallyfinished assemblies and to edges of aluminum sheets where surface treatment has beenremoved as a result of manufacturing or repair operations, or to other surfaces whereimmersion treatment is not practical. Primed, painted, anodized, or hard coated areasadjacent to the area being treated need not be masked, although care shall be taken tokeep the solution off of these areas as much as possible and to rinse off all the solutionafter treatment. Streaks from this method of application, or rundown, of excess solutionsshall not be cause for rejection.

(h) Paint adhesion - Paint adhesion properties of the chromate conversion coating shall besatisfactory when tested per Step 1.E.(3) and Step 1.E.(4).

C. Procedures

(1) Grade B - Manual Application Procedure


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(a) Make up Chromate Conversion coat solutions per paragraph Step 1.D.(1) or 1.D.(2).

(b) Solvent clean per Step 1.C.(2).

(c) Abrasive clean per Step 1.C.(5) (optional).

(d) Mask as required per Step 1.B.(2)(d) and Step 1.C.(3).

(e) Solvent wipe per Step 1.C.(6).

(f) Check for water break free surface.

1 If water breaks, see Step 1.C.(1)(b).

2 If water break free, see Step 1.C.(1)(g).

(g) Activate surfaces with Metal-Glo 6 per MIL-C-38334.

(h) Apply chromate conversion coating. See Step 1.C.(7).

(i) Rinse per Step 1.C.(8).

(j) Air dry - 140°F maximum.

(k) Apply primer, if required, as soon as possible.

NOTE: Handle parts with clean cotton gloves to prevent contamination.

(2) Cleaning - Grease or oil may be removed from assemblies with potential entrapment areas byhand wiping with a clean, lint free cheesecloth dampened with solvent. See 1.B.(1)(b). Wipesolvent from surfaces with clean, dry cheesecloth before evaporation occurs.

(3) Masking - In addition to masking dissimilar metals, surfaces which are not to receive thechromate coating shall be masked, sealed off with plugs, etc. This also applies to potentialentrapment areas that can be practicably converted to no-entrapment areas by masking ordamming for manual application purposes.

(4) Racking - Parts shall be suspended or racked to drain as completely as possible with spaces toavoid contact with each other. Abrasive cleaning (optional) - Abrasive cleaning to remove heattreat discolorations, scale, stains, etc., may be accomplished. See Preparation of Surfaces byAbrasive Methods, 51-28-10, Repair. Do not use abrasive containing iron, such as steel wool,iron oxide, etc. or abrasives that have been used on ferrous alloys.

(5) Abrasive cleaning (optional) - Abrasive cleaning to remove heat treat discolorations, scale,stains, etc. See Preparation of Surfaces by Abrasive Methods, 51-28-10, Repair. Do not useabrasive containing iron, such as steel wool, iron oxide, etc., or abrasives that have been usedon ferrous alloys.

(6) Solvent wipe - Hand wipe with MEK, MPK or acetone and allow to dry.

(7) Application

(a) Apply the Grade B Alodine 1200 or Alodine 600 solution to wet surface as soon aspossible after inspecting for water breaks. Dispense approximately the amount of solutionrequired for the work on hand. Discard after use any solution into which a brush, sponge,or wiper has been dipped. Discard solution if contaminated in any manner.

(b) Apply evenly and liberally with a nylon brush, cotton swab, or lint free clean cheesecloth,using a light pressure and continuous motion. Do not attempt to brush out the solution likepaint. The solution must thoroughly wet the surface and not be allowed to dry on parts. Oncurved or inclined surfaces, begin the application at the lower surface and work upwardsto minimize streaking. Used brushes and cheesecloth must be rinsed before being


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allowed to dry.

(c) Coating solution should be allowed to remain in contact with the part surfaces for the timenecessary, up to 5 minutes, to develop a perceptible color, without producing a powderycoating.

(d) Do not use excessive amounts of water or coating solutions on the surfaces of non-sealed, non drainable assemblies, such as those containing honeycomb, etc.

(8) Rinsing after conversion coating - Rinsing after conversion coating by grade b solutions shall beby swabbing with lint-free, clean cheesecloth saturated with clean water. Repeat with freshwater at least once. Avoid excessive runoff of water near areas of potential entrapment. Rinseat least twice except use a gentle blotting action to avoid damage to fresh chromate film. Blot upexcess water in some manner.

D. Process Control - Grade B Solutions

(1) Alodine 1200

(a) Initial makeup - Fill acid resistant plastic container approximately half full with tap water.

1 For each gallon of final solution, add 4.0 ounces of Alodine 1200 and 0.5 ounce.Nitric Acid, 38° Be.

2 Fill to required volume with water and agitate thoroughly.

3 Keep container closed while not in use.

(b) Operating conditions - Alodine 1200

• Concentration: 4.0 ounce per gallon• Temperature: room temperature• Nitric Acid, 38° Be: 0.5 ounce per gallon

(c) Additional requirements - Make solution fresh at least yearly or more often if functioningimproperly.

(2) Alodine 600 (Use where low dielectric resistant coating is desired).

(a) Initial makeup - Fill acid resistant plastic container approximately half full with tap water.

1 For each gallon of final solution, add 3.0 ounces of Alodine 600 material and 2.5ounces of Alodine Toner 22.

2 Fill to required volume with water and agitate thoroughly.

3 Keep container closed while not in use.

(b) Operating Conditions

• Concentration: 3 ounce per gal• Temperature: room temperature• Alodine Toner: 2.5 ounce per gal

(c) Additional requirements - Make solution fresh at least yearly, or more often if functioningimproperly.

E. Quality Control

(1) Responsibility - The operator shall be responsible for assuring compliance with requirements ofthis specification.

(2) Rejected parts - Rejected parts shall be stripped and retreated.


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(3) Paint adhesion - Tests for paint adhesion shall be performed by the operator for every batch ofconversion coating solution made and used.

(a) Prepare a specimen from 6061-T6 aluminum alloy sheet per QQ-A-250 / 11 or fromexcess or scrap of the same alloy used in the repair.

(b) Test panel size shall be a minimum of 3 x 6 inches and of a like gage to the alloy used inthe repair.

(c) Inspect the test panel prior to processing to ensure that there are no corrosion products,heat treat oxides, gouges, scratches or other conditions that may provide points for theinitiation of corrosion.

(d) Prime test panel with either zinc chromate or epoxy primer. See Epoxy Primer Coating -Preparation and Application (Including Finish 2012), 51-07-10, Repair.

(e) Allow to dry a minimum of 24 hours before testing.

(f) Knife adhesion testing shall be accomplished by butting into the primer film with a sharpknife held so that an angle of approximately 30° is maintained between the blade and thespecimen.

(g) Adhesion is satisfactory if the cut primer film is ribbon like without flaking or separate fromthe specimen beyond the cut.

(4) Tape adhesion - Tape adhesion testing may be performed on the same specimen used for theknife test.

(a) Immerse the test panel in distilled water for 24 hours. Immediately wipe dry with a softcloth and make two parallel scratches, 1 inch apart, through the coating to the metal.

(b) Apply a 1 inch wide strip of tape across the scratches and press tightly against thesurface. See Step 1.B.(1)(b).

(c) Remove the tape with one quick motion and inspect.

(d) If no intercoat separate occurs between the primer and the conversion coating or theconversion coating and the metal, the adhesion is satisfactory.

(5) Deviations - Any deviations from this specification shall be submitted for approval in writing toGulfstream Technical Operations.


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Table 201: Applicable Documents

FEDERAL

QQ-A-250 / 11 Aluminum Alloy 6061, Plate and sheet

0-N-350 Nitric Acid, Technical

MILITARY

MIL-C-5541 Chemical Conversion Coatings on Aluminum AndAluminum Alloys

MIL-C-81706 Chemical Conversion Materials for CoatingAluminum And Aluminum Alloys

MIL-C-38334 Corrosion Removing Compound, Prepaint, ForAircraft Aluminum Surfaces

GULFSTREAM SPECIFICATIONS

Preparation of Surfaces by Abrasive Methods, 51-28-10, Repair

STANDARDS

Individual Process and Finish Codes, 51-20-00, General

ASTM D 740 Methyl Ethyl Ketone (MEK)

ASTM D 329 Acetone

GAS115K Methyl Propyl Ketone (MPK)

2. Cleaning and Chemical Surface Treatment of Aircraft Surfaces

A. General

(1) Scope

This specification establishes the requirements in accordance with MIL-F-18264, for cleaning oftransparent plastics, cleaning of painted surfaces and paint removal.


The following documents shall form a part of this specification to the extent specified. See Table202.

B. Requirements

(1) General - When cleaning and chemical surface treatment of assemblies is required inaccordance with MIL-F-18264, cleaning transparent plastics, cleaning painted surfaces andpaint removal, it shall be accomplished as follows:

(2) Special requirements - Extreme care shall be exercised when applying paint stripper for theremoval of paint finishes from aircraft and assemblies.

(a) Paint stripper shall not come in contact with the following areas:

• Fabric surface• Plastic parts (transparent acrylic)• Interior surfaces (crevices, joints and seams)• Engines



(b) Transparent acrylic plastic shall not be exposed to solvents and cleaners except thoselisted Step 2.B.(4).

(c) Steel wool, steel knives, steel brushes or emery paper, shall not be used for stripping orcleaning.

(3) Equipment - The equipment and facilities used shall conform to MIL-F-18264.

(4) Materials - The following materials are required and shall be used. See Table 203.

C. Procedures

(1) Precleaning - Cleaning shall be accomplished with solvents, steam cleaning compounds,alcoholic phosphoric acid solution maximum 20% acid chemical cleaner or mechanicalprocesses that shall have no deleterious effect on the surface treatment or metal.

NOTE: Reclaimed solvent shall not be used for cleaning purposes.

For fiberglass surfaces steam cleaning shall only be applied for a sufficient time toassure removal of residue from seams and crevices.

Chemical cleaners shall not be used on surface anodized per MIL-A-8625.

(a) Parts shall be cleaned with solvents.

NOTE: Titanium shall be prepared as specified by Gulfstream Technical Operations.

(2) Surface cleanliness - Immediately prior to chemical surface treatment, the cleaned surface shallbe subjected to a water break test and an alkalinity test. See Step 2.D.(2)(a) and Step 2.D.(2)(b).

(a) If the water break test fails, the surface shall be recleaned and retested.

(b) If the alkalinity test fails, the surface shall be rerinsed and retested.

NOTE: Due to the discontinuity of the surface, fastener heads and adjacent areas,joints, seams and nonmetallic surfaces shall not be subject to the water breaktest.

(3) Chemical surface treatment for aluminum alloys - Aluminum alloys shall be surface retreatedwith a chemical solution either by spray or brush.

NOTE: Primed or painted areas or laminated fiberglass adjacent to the area being testedneed not be masked, but shall be thoroughly rinsed after treatment.

(4) Final cleaning - The surfaces shall be wiped using solvents.

NOTE: If the cleaned surfaces are not painted within 8 hours, the final cleaning operation shallbe repeated.

(5) Preparation of nonmetallic surfaces - Peel ply shall be removed when used on fiberglasscomponents.

NOTE: Solvents and abrading shall not be detrimental to the substrates.

(a) Subsequent preparation as specified by Gulfstream Technical Operations shall be usedwhen required.

(b) Nonpeel ply fiberglass and other plastic surfaces shall have release agents removed,solvent cleaned and / or abraded as specified by Gulfstream Technical Operations.

(c) See Epoxy Primer Coating - Preparation and Application (Including Finish 2012),51-07-10, Repair to prepare fiberglass surfaces.


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(6) Preparation of Aged Epoxy Primed Surfaces

(a) Abrasive cleaning - Care shall be exercised to remove only a minimum of primer coating.

(b) Coating shall not be removed to bare metal. Hardened sealant, excess sealant adjacent toseams, dry overspray and other areas of contamination shall be removed during thisoperation.

(c) Solvent / steam cleaning - Abraded surfaces shall be cleaned with a solvent.

1 If evidence of contamination exists the surface shall be cleaned using a steamcleaning compound.

2 When steam cleaning is employed an alkalinity test shall be performed on thesurface. See Step 2.D.(2)(b).

(d) Final cleaning - Surfaces shall be cleaned with solvents.

NOTE: If the cleaned surface is not reprimed within 8 hours, the final cleaning operationshall be repeated.

(7) Primer reactivation - Surfaces shall be reactivated by applying a mist coat of epoxy primer to allsurfaces. See Application of Epoxy Polyamide Primer Coating, 51-07-10, Repair.

(8) Cleaning of finish painted surfaces - Painted surfaces shall be cleaned with a cleaningcompound.

(9) Cleaning of transparent acrylic (plastic) surfaces - All gum or strippable coating residue shall beremoved using a solvent.

(a) Final cleaning shall be accomplished with polish.

(10) Removal of Paint Type Coatings (Stripping)

(a) Preparation of surface for stripping and cleaning - Surfaces shall be adequately protectedby protective coverings, maskants, etc. See Step 2.B.(2).

(b) Stripping - Coatings may be removed by either of the following methods:

(c) Chemical stripper - The dwell time of chemical strippers on nonmetallic surfaces shall belimited to the time required to soften the coatings.

1 Surfaces shall be steam cleaned after chemical stripping.

NOTE: Where paint remover is used, the residue shall not be allowed to enter theshop drainage system.

(d) Vacuum blasting - Prior to vacuum blasting, areas such as hinges, bearings, hydrauliccylinders, static parts, etc., shall be protected. Dwell time shall only be long enough toinsure the complete removal of paint.

(e) Cleaning after stripping - Prior to refinishing, aircraft and assemblies shall be cleaned. SeeStep 2.C.(1).

D. Quality Assurance Provisions

(1) Responsibility - It shall be the responsibility of the organization performing the repair to assurethe conformance with the requirements of this specification.

(2) Process control tests - The following tests shall be verified by inspection immediately prior tothe application of the chemical conversion coating (alodine) to assure surface cleanliness.



(a) Water break test - A film of distilled water shall be atomized on the surface being tested orwiped on with a damp cloth. If there is a water break (the water gathering into separateand distinct droplets) within 25 seconds or if there is a water flash (the water suddenlyforming a continuous film) the surface fails the test. When the water droplets spread andmerge into a continuous film without a sudden flashout, the surface passes the test.

(b) Alkalinity test - Moist, red litmus paper is brought in contact with the surface being tested.If the paper turns color, (red litmus paper turns blue upon contact with alkali) indicating thepresence of an alkaline surface, the surface is unacceptable. When the litmus paper doesnot change color, the surface is acceptable. See Step 2.B.(4) for materials.

E. Notes

(1) Safety precautions shall be adhered to at all times.

(2) When handling dry salts take protective measures by wearing gloves, aprons, etc., as somesalts contain an oxidizing material that can be harmful on contact with the skin.

(3) Dry salts can become spontaneously combustible upon contact with vapors from some solventsand thinners. For this reason, do not store salts near paint, thinners, or solvents. When drawingthe salts from stock, make sure that clean containers are used.

(4) Suppliers (sellers) - This specification shall be applicable for supplier compliance as specifiedby the specifications. Suppliers and operators are required to submit deviation request forapproval, before use of product, to the Gulfstream Technical Operations.


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MILITARY

MIL-C-43616 Cleaning Compound, Aircraft Surfaces

MIL-A-8625 Anodic Coatings, for Aluminum and AluminumAlloys

MIL-F-18264Finishes: Organic, Weapons System, Applicationand Control

MIL-C-22542 Cleaning Compound, Liquid, High PressureCleaner

MIL-R-25134 Remover, Paint and Lacquer, Solvent Type

MIL-R-81294 Remover, Paint, Epoxy System

MIL-C-87936 Cleaning Compound, Aircraft Exterior Surface,Water Dilutable

P-C-437 Cleaning Compound, High Pressure (Steam)Cleaner

P-P-560 Polish, Plastic

TT-I-735 Isopropyl Alcohol

TT-N-95 Naphtha, Aliphatic

TT-R-2918 Remover, Paint, No Hazardous Air Pollutants(HAPS)

GULFSTREAM SPECIFICATIONS

Application of Epoxy Polyamide Primer Coating, 51-07-10, Repair


GAS115K Solvent, Methyl Propyl Ketone (MPK)

GAS115H Solvent, Cleaner / Degreaser - MixedHydrocarbons

ASTM D 329 Acetone



Table 203: Approved Materials

MATERIAL SPECIFICATION

Steam cleaning compounds MIL-C-22542 and P-C-437

Alcoholic - Phosphoric solution

Phosphoric acid (85% by weight), technicalgrade

Isopropyl alcohol per TT-I-735

Butyl alcohol; technical grade

Transparent acrylic plastic cleaners andpolishing materials

Aliphatic naphtha per TT-N-95, Type II

Polish per P-P-560

Solvent cleaners

MPKAcetoneorMixed hydrocarbon

Painted surface cleanerMIL-C-43616orMIL-C-87936, Type II

Chemical cleanerHughson Chemlok EX-B-727-6-Pretreatment -Hughson Chemical Co., Erie, PA

Chemical film material MIL-C-81706

Paint removers

MIL-R-81294

MIL-R-25134

TT-R-2918

Alkalinity indicator Red litmus paper

3. Alkaline Cleaning of Ferrous and Nonferrous Alloys

A. General

(1) Scope

This specification establishes requirements for cleaning of ferrous and nonferrous alloy partsexcept titanium and titanium alloys, in accordance with MIL-S-5002.

B. Applicable Documents

(1) The following documents of latest issue form a part of this specification to extent specifiedherein. See Table 204.

C. Requirements

(1) General - Where specifications require the alkaline cleaning of ferrous and nonferrous alloyparts, it shall be accomplished as follows:

(2) Special requirements

(a) Solution removal - Parts shall be thoroughly rinsed to insure complete solution removal.


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(b) Pre-cleaning - When cleaning is required prior to alkaline cleaning, it shall conform to therequirements of MIL-S-5002.

(3) Equipment - Cleaning solution tanks shall be capable of containing cleaning solutions withoutdeleterious effects on tanks or solutions contained therein.

(a) Facilities shall be provided for maintaining solutions at selected temperatures up to 212°F.

(b) Electrocleaner and deruster solution tanks shall be provided with a suitable direct currentpower source with periodic reverse current capabilities.

(4) Materials - Unless otherwise specified, chemicals shall be of technical grade and commerciallyavailable.

(a) The materials for use, solution concentrations and operating parameters shall be specifiedby or approved by Gulfstream Technical Operations.

(5) Procedure - Parts shall be cleaned by alkaline soak, periodic reverse cleaning, anodic cleaningor other suitable methods within restrictions of Step 3.C.(5)(a), to meet end productrequirements of this specification.

(a) Restrictions - The following restrictions are applicable to ferrous alloys:

1 Alloys in heat treat condition of 165 ksi or above and all springs shall not beprecleaned by acid cleaning.

2 Periodic reverse cleaning shall not be used on alloys in heat treat condition of 200ksi or above.

3 Anodic cleaning shall not be used on alloys in heat treat condition of 220 ksi orabove.

4 When periodic reverse cleaning is employed a variation of 4:1 maximum to 1:1minimum anode to cathode time cycle shall be used.

5 Upon completion of cleaning, parts shall be removed during anodic cycle.

(b) Clean parts handling - Cleaned parts shall be suitably protected and handled to preventcontamination during handling and storage.

D. End Product Inspection

(1) Visual Examination

(a) Alkaline cleaning in accordance with this specification shall produce a visually cleansurface free from pits and evidence of intergranular attack.

E. Notes

(1) Safety - All safety precautions shall be adhered to.

(2) Suppliers (sellers) - This specification shall be applicable for supplier (seller) compliance.Deviations are to be approved by Gulfstream Technical Operations.


GOVERNMENT DOCUMENTS

MIL-S-5002Surface Treatments and Metallic Coatings for Metal Surfaces ofWeapon Systems



4. Cleaning and Descaling of Titanium and Titanium Alloys

A. General

(1) Scope

This specification establishes the requirements for cleaning and descaling of titanium andtitanium alloys in accordance with MIL-S-5002.

B. Applicable Documents

(1) The following documents shall form a part of this specification to the extent specified. See Table205.

C. Requirements

(1) Where repairs or specifications require the cleaning and descaling of titanium and titaniumalloys, it shall be accomplished in accordance with the following:

(a) Restrictions

1 Halogenated Solvents or methyl alcohol shall not be used to clean titanium ortitanium alloys.

2 Detail parts, to degree practical, shall be cleaned and so handled to minimize needfor cleaning as assemblies.

3 When cleaning assemblies, care shall be exercised to assure complete removal ofcleaning solution from crevices and seams.

4 End fittings on tubing shall be displaced from their normal positions to assure noresidual solution is retained.

5 Parts cleaned or descaled shall be handled with clean gloves.

(b) Classification

• Method 1 - Solvent cleaning• Method 2 - Alkaline cleaning• Method 3 - Acid cleaning, descaling (ambient)• Method 4 - Acid cleaning, descaling (elevated temperature)• Method 5 - Acid pickle, cleaning• Method 6 - Abrasive cleaning, descaling

(c) Equipment - The following equipment or equivalent, as approved by Gulfstream TechnicalOperations, shall be used.

1 Tanks

• Alkaline cleaners - Mild steel• Scale conditioners - Materials resistant to corrosive elements of chemicals• Acid solutions - Stainless steel, mild steel with vinyl, rubber or carbon brick

lining• Water rinse - Mild steel with suitable non metallic coating to prevent corrosion

(d) Materials - Unless otherwise specified, chemicals shall be technical grade andcommercially available. See Table 206.

(e) Solution and Equipment Preparation

1 Tanks shall be thoroughly cleaned before make up of new solution.

2 Fill tank one-third to one-half with tap water and add material in Table 207, Table 208


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or Table 209 as applicable.

3 For those baths operated at elevated temperatures, water may be heated andagitated to speed dissolution of material.

4 When material is thoroughly mixed, bring to operating level and temperature.

NOTE: Use care when handling chemicals.

5 Etch rate - Etch rate of acid descaling solutions shall be checked a minimum of oncea day using weight loss method.

a Standard test coupon shall be annealed 6Al-4V titanium sheet 2 inches x 2inches x 0.060 inch - 0.125 inch.

b One test coupon for each acid solution shall be immersed for 20 minutes ±10seconds and resulting loss on weight measured.

c Etch rate as determined by formula (Etch rate (inch / minimum) = weight loss(nearest 0.0001 g) / 11640) shall be recorded and posted in a conspicuousarea.

D. Procedure

(1) The following cleaning and descaling procedure shall be used as applicable.

(a) Method 1 - Solvent cleaning

1 For removal of stencil markings, heavy grease, oil or soil residues.

2 Wipe or immerse material in solvent cleaner per Table 210 as applicable.

(b) Method 2 - Alkaline cleaning

1 For removal of stencil markings, heavy grease, oil or soil residues.

a If required, wipe or immerse material in solvent cleaner per Table 210 or Spraywhite per Table 207.

b Immerse in alkaline cleaner listed per Table 207.

c Cold water rinse for a minimum of 5 minutes.

d Warm water may be used to facilitate drying.

e Dry using clean filtered air or other suitable method.

NOTE: Steel shot peened parts may be pressure sprayed with either air orsteam with alkaline cleaner per Table 207 followed by a water rinse.Repeat Step 4.D.(1)(b)1 b and Step 4.D.(1)(b)1 c as required toremove all traces of shot peen smut.

For tubing only, immerse in alkaline cleaner per Table 207, at ambienttemperature. This shall be followed by an internal flush with alkalinesolution for 1 minute. Cold water rinse for 5 minutes minimum, shallinclude an internal flush for 1 minute minimum. Warm water may beused to facilitate drying.

(c) Method 3 - Acid cleaning / descaling (ambient)

1 For the removal of oxidation scale formed as a result of stress relieving or thermaltreatments below 1450°F.

a Immerse part in scale conditioner per Table 208.



b Water rinse 70°F - 180°F for a minimum of 5 minutes.

NOTE: Pumice water paste applied by sponge may be used to aid inconditioning of tenacious heat treat or forming scale or coatings.

c Follow with water rinse.

d Repeat Step 4.D.(1)(c)1 a and Step 4.D.(1)(c)1 c as required.

e Immerse in ambient acid solution 1 per Table 209 initially for 2 - 3 minutes.

f Cold water rinse for a minimum of 5 minutes.

NOTE: Any residual scale may be removed by water pumice paste, abrasiveblasting, abrasive paper 180 grit or finer or repeat Step 4.D.(1)(c)1 a.Follow with water rinse.

g Repeat Step 4.D.(1)(c)1 e and Step 4.D.(1)(c)1 f as required.

h Immerse in ambient acid descaling solution for sufficient time to remove aminimum of 0.0002 - 0.0005 inch per surface for each intermediate forming orstress relieving operation for which descaling is required. See Table 209.

i Full surface contamination removal subsequent to last forming or stressrelieving operation shall not exceed 0.001 inch per surface.

j Immersion time will be based on bath etch rate as posted.

k Immediately, cold water rinse for a minimum of 5 minutes.

l Dry using clean filtered air or other suitable drying methods.

(d) Method 4 - Acid cleaning / descaling (elevated temperature)

1 For the removal of oxidation scale formed as a result of solution heat treating orthermal treating at temperatures above 1450°F.

2 This method can also be used for sizing or descaling operations requiring at least0.002 inch metal removal per surface.

a Immerse part in Alko-N scale conditioner per Table 208.

b Water rinse 70°F - 80°F for 5 minutes minimum.

NOTE: Pumice water paste applied by sponge may be used to aid inconditioning of tenacious heat treat or forming scale or coatings.Follow with a water rinse.

c Repeat Step 4.D.(1)(d)2 a and Step 4.D.(1)(d)2 b as required.

NOTE: Omit Step 4.D.(1)(d)2 a thru Step 4.D.(1)(d)2 c for sizing operationsand substitute Method 2 prior to the following steps. See Step 4.D.(1)(b).

d Immerse in elevated temperature acid descaling solution initially for 2 - 3minutes. See Table 209.

e Cold water rinse for a minimum of 5 minutes.

NOTE: Any residual scale may be removed by water pumice paste, abrasiveblasting, abrasive paper 180 grit or finer or repeat Step 4.D.(1)(d)2 a.Follow with a water rinse.

f Repeat Step 4.D.(1)(d)2 d and Step 4.D.(1)(d)2 e as required.


51-21-00Page 215

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g Immerse in elevated temperature acid descaling solution for sufficient time toremove a minimum of 0.002 inch per surface. Immersion time will be based onbatch etch rate as posted. See Table 209.

h Immediately, cold water rinse for a minimum of 5 minutes.

i Clean using dry filtered air or other suitable drying method.

(e) Method 5 - Acid pickle / cleaning

1 For pretreating and cleaning surfaces prior to processing, as required, and forremoval of surface contamination formed at temperatures below 1000°F.

a Alkaline clean material per Method 2. See Step 4.D.(1)(b).

b Immerse in ambient solution for removal of 0.001 maximum per surface. SeeTable 209.

NOTE: Where specific removal of material is required for dimensional control,immersion time will be adjusted in accordance with posted batch etchrate.

c Cold water rinse immediately for a minimum of 5 minutes.

d Dry using clean filtered air or other suitable drying methods.

(f) Method 6 - Abrasive cleaning / descaling

1 Alternate method for cleaning or descaling parts.

a Abrasive clean with aluminum oxide. See Preparation of Surfaces by AbrasiveMethods, 51-28-10, Repair.

b Material 0.025 inch or under may be blasted using a maximum air pressure of20 psi.

c Water rinse 70°F - 80°F to remove excess abrasive.

d Immerse in alkaline cleaner per Table 207.

e Cold water rinse for a minimum of 5 minutes.

NOTE: When required, remove residual abrasive material by wiping with asponge saturated with water.

f Immerse in ambient acid solution 1 per Table 209 to remove 0.0005 - 0.001inch per surface for each descaling cycle.

NOTE: No hydrogen analysis is required when chem mill solution is utilizedfor descaling cycle.

g Cold water rinse immediately, for 5 minutes minimum.

h Dry using clean filtered air or other suitable drying methods.

E. Quality Assurance Provisions

NOTE: Any questions regarding these operations may be directed to Gulfstream TechnicalOperations for assistance.

(1) Solution control - The solutions required by this specification shall be analyzed and recorded asare the physical maintenance of the tanks used. This information must be made available toGulfstream Technical Operations.



(2) End product - Materials or parts descaled or cleaned in accordance with this specification shallhave all surfaces completely free of grease, oil, stencil marks, flux, foreign metal contaminantsand heat treat scale and shall meet the surface requirements of MIL-S-5002.

(3) Parts shall be free from pits and intergranular attack.

(a) A sampling of parts cleaned per Method 3, Method 4 or Method 5, shall be taken atrandom for each tank as often as parts are processed. See Table 211.

(b) Within 8 hours after cleaning, sample parts shall be microscopically examined for pitting orintergranular attack.

(c) Welded assemblies, acid cleaned or descaled per this specification, shall have arepresentative weld segment visually examined for evidence of pitting.

(d) Porosity in beads of weldments shall not be construed as pitting or intergranular attackresulting from cleaning process specified herein.

(e) Parts exhibiting evidence of pitting or intergranular attack shall have discrepant conditionmechanically removed, if possible, within limits imposed by Gulfstream TechnicalOperations.

(f) Materials not meeting requirements of this specification shall be subject to rejection orsubmitted to Gulfstream Technical Operations for appraisal.

F. Notes

(1) Safety - All safety precautions shall be adhered to.

(2) Suppliers (Sellers)

(a) This specification shall be applicable for supplier (seller) compliance.

(b) All deviations must be submitted in writing for approval to Gulfstream TechnicalOperations.


INDUSTRY

ASTM D 740 Methyl Ethyl Ketone (MEK)

ASTM D 329 Acetone

ASTM D 770 Isopropyl Alcohol

FEDERAL

MIL-S-5002 Surface Treatments and Metallic Coatings forMetal Surfaces of Weapon Systems


TT-T-548 Toluene

GULFSTREAM


GAS115HSolvent - Cleaner / Degreaser - MixedHydrocarbons

GAS115K Solvent - Methyl Propyl Ketone (MPK)


51-21-00Page 217

February 29/04

Table 206: Approved Materials

MATERIAL SPECIFICATION MANUFACTURER

Nonchlorinated Solvents

Penetone TPC Penetone Corp.

MEK ASTM D 740

Acetone ASTM D 329

Isopropyl alcohol TT-I-735

MPK GAS115K

Hydrocarbon cleaners GAS115H

Alkaline Cleaners (Non-etch)

Oakite 164 Oakite Corp.

Ridoline 53 Amchem Corp.


Ridosol 66-9 Amchem Corp.

Spray white Kelite Corp.

Aerowash Wyandotte Chem. Co.


Pennwalt Cleaner 45 Penwalt Corp.

Scale Conditioners

Sodium hydroxide (Caustic)

Alko-N Salts Kolene Corp.

Pumice 3F

AbrasivesSee Preparation of Surfaces by Abrasive Methods,

51-28-10, Repair

Acids

Nitric acid 42°Be’

Hydrofluoric acid - 70percent (by weight)

Actane 70 Enthone, Inc.

Wetting Agents

Nacconol 98SA Allied Chemical



Table 207: Alkaline Cleaners

MATERIAL CONCENTRATIONS TEMPERATURE °F IMMERSION TIME (1)

Ridoline 53 2 - 10 oz / gal. 140 - 1805 - 30 minutes /

immersion

Ridoline 53 withRidosol 66-9 (2) 2 - 10 oz / gal. 140 - 180

5 - 30 minutes /immersion

Oakite 164 2 - 10 oz / gal. 140 - 1805 - 30 minutes /

immersion

Ridoline 70 3 - 6 oz / gal 140 - 1805 - 30 minutes /

immersion

Spray white40 - 60 percent by

volumeAmbient

5 - 30 minutes / wipeon or immersion

Aerowash10 - 30 percent by

volumeAmbient to 190

5 - 30 minutes /pressure spray or

immersion

Ridoline 27 1 - 5 oz / gal 120 - 2005 - 30 minutes /

immersion

Pennwalt Cleaner 45 4 - 10 oz / gal 140 - 2125 - 30 minutes /

immersion(1) Immersions in solutions may be repeated as necessary.(2) Additions of Ridosol 66-9 will be made as directed by Gulfstream Technical Operations. Chemical analysis of Ridosol

66-9 is not required.

Table 208: Scale Conditioners

MATERIAL CONCENTRATIONS TEMPERATURE °F IMMERSION TIME (1)

Alko-N Salts As received (2) 400 - 4251 - 5 minutes /

immersion

Sodium hydroxide(caustic)

5 - 40 percent byweight

160 - 20015 - 30 min /

immersion(1) Immersions in solutions may be repeated as necessary.(2) Additions of Alko-N Salts shall be approved by Gulfstream Technical Operations.

Table 209: Acid Descaling Solutions

MATERIAL CONCENTRATION TEMPERATURE (F°) IMMERSION TIME

Nitric acid(1) 35 - 45 percent byvolume

Ambient (85°maximum)

(1)

Hydrofluoric acid(2)

or1.5 - 3 percent by

volume

Actane 70 (2) 1.5 - 3 percent byweight

Nacconol 98S (3) 8 - 16 fluid oz. per1000 gallons


51-21-00Page 219

February 29/04

MATERIAL CONCENTRATION TEMPERATURE (F°) IMMERSION TIME

Nitric acid (1) 35 - 45 percent byvolume

120 - 140 (4)Hydrofluoric acid (2)

or1.5 - 3 percent by

volume

Actane 70(2) 1.5 - 3 percent byweight

(1) See Step 4.D.(1)(c)1 h.(2) Hydrofluoric acid and Actane No. 70 may be interchanged as required.(3) Additions of Nacconol 98S will be made as directed by Materials Engineering. Chemical Analysis of Nacconol 98S is not

required.(4) See Step 4.D.(1)(d)2 h.

Table 210: Solvent Cleaners

MATERIAL CONCENTRATIONS TEMPERATURE °F IMMERSION TIME

Penetone TPC As received AmbientWipe on or immerse

as required

MPK As received AmbientWipe on or immerse

as required

Isopropyl alcohol As received AmbientWipe on or immerse

as required

Acetone As received AmbientWipe on or immerse

as required

MEK As received AmbientWipe on or immerse

as required

Mixedhydrocarbon

solventAs received Ambient

Wipe on or immerseas required

Table 211: Intergranular Attack

LOT SIZESAMPLE

SIZEACCEPTANCE

NUMBERREJECTION

NUMBER

5 - 50 2 0 1

51 - 500 3 0 1

501 - 1200 5 0 1

5. Aerodynamic Sealant Compound

A. Requirements

(1) General

Unless otherwise specified, only the listed products and vendors are approved. See Table 212.

(a) Approved Vendors



The following are approved vendors:

• Products Research Chemical Corp. Gloucester City, New Jersey (FSCM 05027)• PRC / ProSeal Compton, CA (FSCM 83527)

(b) Material

Two part polysulfide. Room temperature curing thixotropic paste.

Unless otherwise specified, dimensions are in inches.

Unless otherwise specified, material testing per Table 214 shall be conducted at 77°F±2°F and 50 ±5 percent relative humidity.

Color - Aluminum or Metallic Gray.

Work life: 30 - 60 minutes.

Cure time: (to attain shore ″A″ hardness of 25) 24 hours maximum.

Nonvolatile content: 97 percent minimum.

Adhesion (peel strength): 10 pounds per inch, minimum.

Adhesion (peel strength): After 24 hours immersion in JP-5 jet fuel: 7 pounds per inchminimum.

Adhesion (peel strength): After 24 hours immersion in MIL-H-5606 hydraulic oil: 7 poundsper inch minimum.

Units of measure are in USA units.

Usage: these items are intended for use on the exterior of aircraft to provide aerodynamicsmoothness, to seal seams against weather and fuel spillage and to prevent fayingsurface corrosion from cleaning compounds.

B. Acceptance Test Requirements

(1) See Table 214 for acceptance requirements.

(2) Storage life - The items (base and catalyst) shall be capable of meeting all the requirementsspecified herein when stored in their original unopened containers at 80°F or below for thefollowing specified period. See Table 213.

(a) After the original shelf life period has expired, the materials may be requalified once forimmediate use within a 72 hour period if the requirements of are met. See Table 214.

(b) The maximum material shelf life shall not exceed the original shelf life period by more than1 month regardless of when the requalification was performed and passed.

(c) If the material is requalified, the new expiration date and a statement that the material hasbeen requalified must be legibly added to its containers.

(d) Each container of sealant is accompanied by a separate container of catalyst. The sealantand catalyst containers may be assembled as a single unit or kit.

(e) Environmental, safety and waste requirements shall be as is applicable to federal, stateand local regulations.

(3) Personnel - Only personnel qualified and experienced with the mixing, testing and application ofthe materials specified herein are authorized to utilize them in a manner consistent withstandard aerospace practices and procedures.


51-21-00Page 221

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Table 212: Approved Sealant

COAST PRO-SEALITEM NUMBER

PRODUCTSRESEARCH ITEM

NUMBER

APPROX. WEIGHTLBS / GAL.

Pro Seal 895-1 PR340 13 - 16

Table 213: Storage Life

MATERIAL SHELF LIFE

Pro Seal 895 6 months

PR 340 12 months

Table 214: Sealant Acceptance Requirements

PROPERTY VALUE TEST SPECIMEN TEST METHOD

Work life 30 - 60 minutesCatalyze 150 grams and mixthoroughly for 3 - 5 minutes in a metalor glass container.

Transfer to an untreated cardboard orpaper container.Insert a glass rod into the sealant andwithdraw sealant that clings to the rod aminimum of 6 inches.When sealant string breaks and retractswithin the 6 inch distance, the sealant isno longer workable.Repeat test three to five times andaverage results.

Cure time toattain minimumhardness of 25shore A

24 hoursmaximum

Test slab 1/4 inch thickminimum length and width to suit.

Measure time required to reach specifiedhardness.Measure hardness with a shore ″A″durometer (instantaneous reading).

Adhesion (peelstrength)

See material inStep 5.A.(1)(b).

Prepare test panels of cleanedAlodined or anodized aluminum alloy,4X6X0.040.Mask off a 3 inch wide strip acrosswidth of panel.Apply accelerated sealant 1/8 to 1/4inch thick on entire panel.Place 4X8 piece of open weave glassfabric over the sealant so that oneend of the glass cloth coincides withthe unmasked portion of the panel.Press the cloth into the sealantallowing 1/8 inch excess sealant overthe cloth.Cure for 48 hours minimum andimmerse where applicable in test fluid.Cut three 1 inch strips through to thealuminum the full length of the cloth.Do not use panel edges as test strips.

Mount panel in tensile tester.The masked end in one jaw, the loose endin the other jaw in a manner such that thefabric is folded 180° to itself as it leavesthe panel.Pull at approx. 2 inches per minute tofailure.

Base viscosity 13000 ±3000poise

Base compound thoroughly mixed, inoriginal container.

Model RVF Brookfield Viscosimeterusing a 7 inch spindle at 2 RPM.


51-21-002February 29/04

6. Fuel Resistant Sealing Compound — Fillet and Faying (−65°F to +360°F Service)

A. General

(1) Scope

This specification establishes the requirements for curing MIL-S-83430 Type sealants in thetemperature range of −65°F to 360°F, for general purpose use in integral fuel tanks, cabinpressure sealing and as aerodynamic smoothing compounds.


The following documents shall form a part of this specification. See Table 215.

B. Classification

(1) The materials used in accordance with this specification shall be designated to the followingthree parameters:

• Type - see Step 6.B.(2)• Class - see Step 6.B.(3)• Dash Number - see Step 6.B.(4)

(2) Type - The material shall be designated by one digit as indicated below:

(a) Type I extrudable fillet (hydrolytically stable) - Designation 1

(b) Type III faying surface (hydrolytically stable) - Designation 3

(3) Class - The material class shall be designated by a letter as indicated below:

(a) Class B Two Part Designation B

NOTE: Class designators are intended for procurement purposes. Operators shall usedesignator 0 if specific class designation is not specified in the repair or is notrequired.

(4) Dash numbers - Work life dash numbers shall be used to designate the appropriate number ofhours before the mixed material becomes unsuitable for application due to advancing cure.

- 1/2 Hour work life Designation 1

- 2 Hour work life Designation 2



NOTE: Dash numbers are intended for procurement purposes. Operators shall usedesignator 0 if specific class designation is not specified in the repair or is notrequired.

C. Requirements

NOTE: This specification shall have precedence over all applicable subsidiary specifications.

(1) General - The sealing compound covered by this specification shall be of uniform blend,homogeneous, free of skins, lumps and gelled or coarse particles. When components aremixed according to the manufacturers instructions, a smooth, uniform consistency shall result.

(2) Properties - The sealing compound used in conjunction with this manual shall meet thefollowing requirements.


51-21-00Page 223

February 29/04

(a) Viscosity

(b) Type I - When tested, the viscosity of Type I sealant base shall be within the range of10000 - 16000 poises. The viscosity of the Type I sealant catalyst shall be within the rangeof 500 - 1000 poises. See Step 6.D.(6)(a).

(c) Type III - When tested, the viscosity of Type III sealant base shall be within the range of1000 - 3000 poises. The viscosity of the Type III sealant catalyst shall be within the rangeof 500 - 1000 poises. See Step 6.D.(6)(a).

(d) Flow - Type I sealant shall exhibit a flow within the limits of 0.10 - 0.25 inch. See Step 6.D.(6)(b).

(e) Work life - The minimum work life for Type I and Type III sealant shall be 1/2, 2, 6 or 20hours, as applicable. The end of the work life shall be considered when the extrusion rateis less than 15 grams per minute for Type I and less than 30 grams per minute for Type III.See Step 6.D.(6)(c).

(f) Tack free time - When tested, Type I and Type III sealants shall cure to a tack freecondition in the time specified in Table 216. See Step 6.D.(6)(d).

(g) Hardness - When tested, Type I and Type III sealants shall have an instantaneousminimum 25 hardness, after curing under standard conditions in the time specified inTable 216. See Step 6.D.(6)(e).

(h) Peel Strength - When tested, cured Type I and Type III sealants shall have a minimumpeel strength of 20 pounds per inch width. The adhesive strength shall exceed thecohesive strength. Failure shall be 100 percent cohesive except for bubbles, knife cutsand other causes that are obviously not the fault of the sealants. See Step 6.D.(6)(f) andTable 217.

D. Quality Assurance Provisions

(1) Inspection - Unless otherwise noted, the seller is responsible for the performance of all theinspection requirements specified herein. The operator may utilize his own test facilities or anycommercial laboratory acceptable to Gulfstream Technical Operations.

(2) Certificate of conformance - The seller shall furnish with each shipment, a certified report (intriplicate) signed by a duly authorized representative of the seller, stating conformance to therequirements specified herein and listing the specific results of all the acceptance tests. Thereport shall also include the purchase order number and the batch number.

(3) Test Conditions

(a) Standard conditions - Unless otherwise specified herein, all tests shall be conducted at atemperature of 77°F ±2°F and a relative humidity of 50 ±5% percent maximum.

(b) Standard cure - Unless otherwise specified, the standard cure shall consist of 14 days 4hours at standard conditions stated in Step 6.D.(3)(a).

(c) Accelerated cure - Accelerated cure, when specified herein, shall consist of 48 ±4 hours atstandard conditions followed by 24 ±1 hours at 140°F ±2°F.

(4) Test Specimens

(a) Test panel preparation - Unless otherwise specified herein, the test panels shall consist ofaluminum alloy (2024) conforming to Specification QQ-A-250 / 4, Temper T81. Test panelsshall be cut to the dimensions required by the test method prior to cleaning and surfacetreatment. Test panels for titanium will be supplied by Gulfstream Technical Operations.



(b) Cleaning - The test panels and fixtures shall be cleaned using solvent per MIL-C-38736 orASTM D 740. See Cleaning and Descaling of Titanium and Titanium Alloys, 51-21-00,Repair for Titanium panels cleaning instructions.

(c) Surface treatment - All test panels and fixtures coming into contact with sealant shall bechemical film coated in accordance with Specification MIL-C-5541, Type II, Class 2.

(d) Corrosion protection coating - When specified in the test method, a coating perSpecification MIL-C-27725 shall be applied after preparation in Step 6.D.(4)(b). Thecoating may be applied to a thickness of 0.0006 - 0.0009 inches. See Integral Fuel TankCoating - MIL-C-27725 Application, 51-22-00, Repair.

(e) Priming - A primer shall be applied after the panels are prepared per Step 6.D.(4)(b) andStep 6.D.(4)(c). The primer may be applied in accordance with Epoxy Primer Coating -Preparation and Application (Including Finish 2012), 51-07-10, Repair or Application ofEpoxy Polyamide Primer Coating, 51-07-10, Repair.

(f) Sealant preparation - The sealant shall be prepared in accordance with themanufacturer’s instructions.

(g) Mixing - Mixing shall be accomplished in a Semco Model 1394 or Model S1350 mixer ormanually.

1 The mixed sealant shall have a minimum inclusion of air. Where applicable, thesealant, immediately after mixing, shall be placed into cartridges for extrusion froman application device.

(5) Formulation of Jet Reference Fluid

FORMULATION OF JET REFERENCE FLUID

Cyclohexand (Technical grade) 60 volumes

Toluol (Spec. TT-T-548) 30 volumes

Iso Octane (Spec. TT-S-735, Type 1) 10 volumes

Tert (Dibutyl Disulfide) 1 volumes

Tert (Butyl Mercaptan)0.015 ±0.00015 weight percent of other fourcomponents

(6) Acceptance Test Methods

(a) Viscosity - Stabilize the base and catalyst compounds at standard for a minimum of 8hours prior to testing. See Step 6.D.(3)(a).

1 The designated Brookfield Viscosimeter shall be used and the readings obtainedconverted to poises.

2 For Type I base compounds, the Brookfield Model RVF Viscosimeter with a No. 7Spindle at 2 rpms shall be used.

3 For Type I catalyst compounds the Brookfield Model RVF Viscosimeter with a No. 6Spindle at 10 rpm shall be used.

4 For Type III base compounds the Brookfield Model RVF Viscosimeter with a No. 6Spindle at 2 rpm shall be used.

5 For a Type III catalyst compound the Brookfield Model RVF Viscosimeter with a No.


51-21-00Page 225

February 29/04

6 Spindle at 10 rpm shall be used.

6 Readings shall be taken after the instrument has run in the material for 1 minute.

(b) Flow test procedure - The flow test jig shall be placed on a table with the front face upwardand the plunger depressed to the limit of its travel.

1 Within 15 minutes after the beginning of mixing, enough of the mixed sealant shallbe extruded from the application gun to fill the recessed cavity of the jig and beleveled off even with the block.

2 Within 10 seconds after the leveling operation, the jig shall be placed on its end andthe plunger immediately advanced to the limit of its forward travel.

3 The flow measurement shall be taken exactly 30 minutes after the sealant has beenapplied to the jig.

4 The flow shall be measured from tangent to the lower edge of the plunger to thefarthest point to which the flow has advanced.

(c) Work life - The base compound, accelerator and application gun shall be stabilized atstandard conditions for at least 8 hours before minimum of 250 grams of base compoundis mixed with the proper amount of accelerator. See Step 6.D.(3)(a).

1 The mixed sealant shall be promptly used to fill a standard Semco sealing guncartridge, or equal, having a Semco 440 nozzle with an orifice diameter of 0.125±0.005 inch.

2 The gun and sealant shall be maintained at standard conditions throughout the test.

3 The gun shall be attached to a constant air supply 90 ±5 psi for line variation or gageerror.

4 From 2 - 3 inches of sealant shall be extruded initially to clear trapped air.

5 At the end of the rated work life, measured from the beginning of the mixing period,the sealant shall be extruded into a suitable receptacle for 1 minute and weighed.

(d) Tack free time - An aluminum test panel 0.040 x 3.00 x 6.00 inches shall be cleaned andcovered with freshly mixed sealant to a depth of 0.125 ±0.0625 inch. See Step 6.D.(4)(a)and Step 6.D.(4)(b).

1 The sealant shall be allowed to cure at standard conditions for the applicable tackfree time specified in Table 216.

2 At the end of the specified tack free time, two 1 x 6 inch pieces of polyethylene film0.004 ±0.002 inch thick shall be applied to the sealant and held in place at apressure of 1/2 ounce per square inch for 2 minutes.

3 The strips shall then be slowly and evenly withdrawn at right angles to the sealantsurface.

4 The polyethylene film shall be dry and free of sealant.

(e) Hardness - The hardness shall be determined with a Shore A Durometer in accordancewith ASTM D 2240 after the sealant is allowed to cure as specified in Step 6.C.(2)(g).

1 The reading should be taken on a doubled back to back 0.125 inch thick specimen.

2 The instantaneous hardness shall be recorded.

(f) Peel strength - Aluminum panels, 0.040 x 3.00 x 6.00 inches shall be prepared for this



test. See Step 6.D.(4)(a).

1 All panels shall first be prepared per Step 6.D.(4)(b) and Step 6.D.(4)(c).

2 They shall then be further prepared as required. See Table 217.

3 After preparation, the panels shall be coated on one side with sealant to a thicknessof 0.125 inches ±0.0625 inches.

4 After the sealant has immobilized, a strip of screen 3.00 x 12.0 inches of 20 - 40mesh aluminum or Monel wire shall be cleaned and impregnated with sealant so thatapproximately one half of its length is completely covered on both sides. See Step 6.D.(4)(b).

5 The sealant must be worked well into the screen. The impregnated ends of the fabricshall be placed on the coated panel and smoothed down on the layer of sealant,taking care not to trap air beneath the fabric and leaving a loose end 6 inches inlength.

6 An additional 0.006 inch thickness of sealant shall be applied over the screen strips.

7 Panels shall be given standard cure. See Step 6.D.(3)(b). After cure, the panels shallbe given the conditioning specified. See Table 217.

8 Where immersion is required, the immersion shall be in suitable vessels with notmore than one panel per pint of fluid.

9 After exposure, the panels shall be cooled in the test media for 24 hours at standardconditions.

10 All panels shall be tested, including the controls.

11 The peel strength of conditioned panels shall be measured within 30 minutes fromremoval from the test fluid.

12 Two 1 inch wide test sections shall be prepared by cutting completely along the freeend of the screen to the panel, length wise along the panel and continuingcompletely along the free end of the screen.

13 The test sections shall be stripped back at an angle of 180° to the panel in a suitabletensile test machine.

14 Jaw separation rate shall be 2 inches per minute.

15 During the peel strength testing, three cuts shall be made through the sealant to thepanel in an attempt to promote adhesive failure.

16 The cuts shall be at approximate 1 inch intervals.

17 The peel strength for each specimen shall be the numerical average of the peakloads to separate the strips of sealant from the panel.

18 Failures of the sealant to the fabric shall not be included in the peel strength values.

NOTE: Test per Table II, No. 1 and No. 2 or No. 3 as applicable for sealant type.Specimens for Test 1 and Test 3 may be given the accelerated cure in lieuof the standard cure. See Step 6.D.(3)(b).

E. Notes

(1) Intended use - The material procured in accordance with this specification is intended for use inaircraft applications, as a general purpose sealant for integral fuel tanks, cabin pressure sealing


51-21-00Page 227

February 29/04

and aerodynamic smoothing.

(2) Product availability - Material designations and approved sellers are listed in Table 218.

NOTE: All test conditions shall include a standard cure prior to any other conditioning. SeeStep 6.D.(3)(c).


FEDERAL

QQ-A-250 / 4 Aluminum Alloy, Plate and Sheet 2024

TT-T-548 Toluene, Technical


MILITARY

MIL-C-5541Chemical Conversion Coatings for Aluminum andAluminum Alloys

MIL-P-23377Primer Coating: Epoxy Polyamide, Chemical andSolvent Resistant

MIL-C-27725Coating, Corrosion Preventative, for AircraftIntegral Fuel Tanks

MIL-C-38736 Cleaning Compound, Solvent Mixtures, Metric

MIL-S-83430Sealing Compound, Integral Fuel Tanks and FuelCell Cavities, Intermittent Use to 360°F

INDUSTRY

ASTM D 740 Methyl Ethyl Ketone

ASTM D 2240Property - Durometer Hardness, Standard TestMethod for

SPECIFICATIONS

Integral Fuel Tank Coating - MIL-C-27725 Application, 51-22-00, Repair

Application of Epoxy Polyamide Primer Coating, 51-07-10, Repair

Cleaning and Descaling of Titanium and Titanium Alloys, 51-21-00, Repair



Table 216: Tack Free and Hardness Time

TEST DASH NUMBER

Tack free time - hours maxSee Step 6.D.(6)(d).

- 1/2- 2- 6- 20

10244896

Hardness - hours maxSee Step 6.D.(6)(e).

3072120240

Table 217: Test Panels

TESTNO.

SEALANTTYPE

PANELPREPARATION(1) SPECIMEN CONDITIONING

1 I1 panel per Step 6.D.(4)(c) 14 days ±4 days at 140°F

±2°FSee Step 6.D.(5)1 panel per Step 6.D.(4)(d)

2 II Same as test 1Standard cureSee Step 6.D.(3)(b)

3 III1 panel with 0.0006 - 0.0009 inchthick coat of MIL-P-23377 primerSee Step 6.D.(4)(e)

Standard cureSee Step 6.D.(3)(b)

(1) See Step 6.D.(4)(a).

Table 218: Material Designations And Approved Sellers

TYPE CLASS NAME MANUFACTURER

I

B - 1/2ProSeal 899 B - 1/2 Essex Chemical Corp.

PR 1741 B - 1/2 Products Research and Chemical Corp.

B - 2ProSeal 899 B - 2 Essex Chemical Corp.

PR 1741 B - 2 Products Research and Chemical Corp.


51-21-00Page 229

February 29/04

TYPE CLASS NAME MANUFACTURER

III

B - 1/2 ProSeal 899 C - 1/2 Essex Chemical Corp.

B - 1/2 PR 1741 C - 1/2 Products Research and Chemical Corp.

B - 2 ProSeal 899 C - 2 Essex Chemical Corp.

B - 2 PR 1741 C - 2 Products Research and Chemical Corp.

B - 6 ProSeal 899 C - 6 Essex Chemical Corp.

B - 6 PR 1741 C - 6 Products Research and Chemical Corp.

C - 20 ProSeal 899 C - 20 Essex Chemical Corp.

C - 20 PR 1741 C - 20 Products Research and Chemical Corp.

