Standard - MIL-STD-2199A Glass Reinforced Plastic Covering for Propeller Shafts.pdf

AMSC N/A FSC 9330

INCH-POUND

MIL-STD-2199A(SH)

26 July 2010

SUPERSEDING

MIL-STD-2199(SH)

11 May 1990

DEPARTMENT OF DEFENSE

STANDARD PRACTICE

COVERINGS FOR WATERBORNE MAIN PROPULSION

SHAFTING ON U.S. NAVAL SURFACE SHIPS AND

SUBMARINES

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MIL-STD-2199A

i

FOREWORD

1. This standard is approved for use by the Department of the Navy and is available for use by all Departments and Agencies of the Department of Defense.

2. The four-layer shaft covering system [primer, elastomeric coating, sealing/fairing compound, and glass reinforced plastic (GRP), as described in this standard, is intended to provide corrosion prevention of waterborne propulsion shafting on U.S. Naval surface ships and submarines for a period of up to 15 years before requiring renewal.

3. This standard provides requirements and guidance in application procedures in sufficient detail to allow personnel with limited experience to apply an effective shaft covering for corrosion prevention. It also provides guidance for dry dock as well as waterborne inspection/repair of the shaft covering.

4. This standard is intended for use by Contractor, Shipyard, and Regional Maintenance Center (RMC) personnel who inspect, install, or repair propulsion shaft coverings on U.S. Naval surface ships and submarines.

5. Comments, suggestions, or questions on this document should be addressed to: Commander, Naval Sea Systems Command, ATTN: SEA 05S, 1333 Isaac Hull Avenue, SE, Stop 5160, Washington Navy Yard DC 20376-5160 or emailed to CommandStandards@navy.mil, with the subject line “Document Comment”. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at https://assist.daps.dla.mil.

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CONTENTS

PARAGRAPH PAGE

1. SCOPE

1.1 Scope

2. APPLICABLE DOCUMENTS

2.1 General

2.2 Government documents

2.2.1 Specifications, standards, and handbooks

2.2.2 Other Government documents, drawings, and publications

2.3 Non-Government publications

2.4 Order of precedence

3. DEFINITIONS AND ACRONYMS

3.1 Definitions

3.1.1 Abrasive-blasting

3.1.2 Cure (or curing)

3.1.3 Elastomeric coating

3.1.4 Fair

3.1.5 Glass reinforced plastic (GRP)

3.1.6 Laminating resin

3.1.7 Peel ply

3.1.8 Pot life (working life)

3.1.9 Primer

3.1.10 Sealing/fairing compound

3.1.11 Sleeve

3.1.12 SSPC-SP 1

3.1.13 SSPC-SP 5

3.1.14 Tack

3.1.15 Thixotropic

3.1.16 Wet-out

3.2 Acronyms

3.2.1 AER – Alteration equivalent to repair

3.2.2 AFT – After

3.2.3 AMS – Aerospace material specifications

3.2.4 AMSDL – Acquisition management systems and data requirements control list

3.2.5 CFR – Code of Federal Regulations

3.2.6 CID – Commercial Item Description

3.2.7 CPP – Controllable pitch propeller

3.2.8 CuNi – Copper-nickel

3.2.9 DoD – Department of Defense

3.2.10 DTNSRDC – David Taylor Naval Ship Research and Development Center

3.2.11 EPA – Environmental Protection Agency

3.2.12 ft2 – Square feet

3.2.13 GRP – Glass reinforced plastic

3.2.14 MIL – Military

3.2.15 MS – Maintenance standard

3.2.16 MSDS – Material safety data sheet

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PARAGRAPH PAGE

3.2.17 NACE – National Association of Corrosion Engineers

3.2.18 NAVSEA – Naval Sea Systems Command

3.2.19 NSTM – Naval Ships’ Technical Manual

3.2.20 r/min – Revolutions per minute

3.2.21 RMC – Regional maintenance center

3.2.22 SAE – Society of Automotive Engineers

3.2.23 SSPC-SP – Steel Structures Painting Council Surface Preparation

3.2.24 TRS – Technical repair standard

3.2.25 VOC – Volatile organic compound

3.2.26 VPI – Vapor phase inhibitor

4. GENERAL REQUIREMENTS

4.1 Recycled, recovered, or environmentally preferable materials

4.2 Personnel

4.3 Facilities, tools, and equipment

4.4 Shaft covering system performance

5. DETAILED REQUIREMENTS

5.1 Materials

5.1.1 First layer – primer

5.1.2 Second layer – elastomeric coating

5.1.3 Third layer – sealing/fairing compound

5.1.4 Fourth layer – GRP

5.1.4.1 Laminating resins

5.1.4.1.1 Cure

5.1.4.2 Glass reinforcement

5.2 Auxiliary materials

5.2.1 Thixotropic filler

5.2.2 Fairing compound for shaft

5.2.3 Coating for flange couplings

5.3 Estimation and preparation of the basic materials required

5.3.1 First layer – primer

5.3.2 Second layer – elastomeric coating

5.3.3 Third layer – sealing/fairing compound

5.3.4 Fourth layer – GRP

5.3.4.1 Laminating resin

5.3.4.1.1 Example of epoxy laminating resin

5.3.4.1.2 Preparation of epoxy laminating resins

5.3.4.1.3 Fillers

5.3.4.2 Fiberglass tape

5.3.4.2.1 Example of calculation for fiberglass tape

5.3.4.2.2 Preparation of fiberglass tape

5.4 Safety precautions

5.4.1 General

5.4.2 Specific precautions

5.5 Facility requirements

5.5.1 Shaft preparation, primer application, and elastomeric coating application

5.5.1.1 Ventilation

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PARAGRAPH PAGE

5.5.1.2 Reaction spray equipment

5.5.2 Third and fourth layers – sealing/fairing compound and GRP application

5.5.2.1 Lathe

5.5.2.2 Temperature

5.6 Application instructions

5.7 Inspection and repair

6. NOTES

6.1 Intended use

6.2 Acquisition requirements

6.3 Subject term (key word) listing

6.4 Changes from previous issue

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PARAGRAPH PAGE

APPENDIX A

A.1 SCOPE

A.1.1 Scope A.1.2 General description

A.2 APPLICABLE DOCUMENTS

A.2.1 General A.2.2 Government documents

A.2.2.1 Specifications, standards, and handbooks A.2.2.2 Other Government documents, drawings, and publications A.2.2.3 Non-Government publications

A.2.3 Order of precedence

A.3 PROCEDURE

A.3.1 Shaft assembly preparations A.3.1.1 Preparation of shaft body areas and interfacing sleeve end prep areas A.3.1.2 Preparation of waterborne shaft flange assemblies

A.3.1.2.1 Shaft flanges enclosed within rotating coupling covers A.3.1.2.2 Coated flanges normally exposed to seawater

A.3.1.3 Preparation of the shaft-to-sleeve end interfaces A.3.1.3.1 Preserving the sleeve end prep area A.3.1.3.2 Sleeve masking precautions

A.3.2 Shaft covering system application A.3.2.1 First layer – primer application A.3.2.2 Second layer – elastomeric coating application A.3.2.3 Third layer – sealing/fairing compound application A.3.2.4 Fourth layer – GRP application A.3.2.5 Cure A.3.2.6 Painting

A.3.3 Flange preservation A.3.3.1 Shaft flanges enclosed within rotating coupling covers A.3.3.2 Shaft flanges normally exposed to seawater

APPENDIX B

B.1 SCOPE

B.1.1 Scope

B.2 APPLICABLE DOCUMENTS

B.2.1 General B.2.2 Government documents B.2.3 Order of precedence

B.2.2.1 Other Government documents, drawings, and publications

B.3 QUALITY CONTROL

B.3.1 Shaft covering inspections B.3.1.1 Post application inspection and repair

B.3.1.1.1 Inspection B.3.1.1.2 Corrective action

B.3.1.2 Dry-dock inspection and repair

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PARAGRAPH PAGE

B.3.1.2.1 Inspection B.3.1.2.2 Repair (for shafts possessing the four-layer covering system)

B.3.1.2.2.1 Repair of visible surface defects B.3.1.2.2.2 Repair of unbonded GRP B.3.1.2.2.3 Repair of damaged areas not in way of sleeve ends B.3.1.2.2.4 Repair of damaged areas in way of sleeve ends

B.3.1.2.3 Repair (for shafts possessing only a GRP layer) B.3.1.2.3.1 Repair of visible surface defects B.3.1.2.3.2 Repair of unbonded GRP B.3.1.2.3.3 Repair of damaged areas not in way of sleeve ends B.3.1.2.3.4 Repair of damaged areas in way of sleeve ends

B.3.1.3 Waterborne inspection and repair B.3.2 Reports

FIGURE PAGE

A-1. A typical shaft and sleeve configuration, prepped for the shaft covering A-2. Schematic showing the primer (the entire shaft and sleeve end are covered) A-3. Plural component reaction spray equipment A-4. Pre-mix of the elastomeric coating components A-5. Charging the reaction spray equipment with the components A-6. Application of elastomeric coating by reaction spray at a shipyard A-7. Reaction spray of elastomeric coating A-8. Schematic showing the elastomeric coating (the entire shaft and sleeve end are covered) A-9. Mixing a kit of sealing/fairing compound A-10. Schematic showing sealing/fairing compound (only the sleeve end area is covered) A-11. Fairing the shaft/sleeve interface with sealing/fairing compound A-12. Completion of shaft-to-sleeve fairing with sealing/fairing compound A-13. View of gray sealing/fairing compound applied over second layer of elastomeric coating (black) A-14. Completed GRP application, shown fair with the sleeve A-15. Schematic showing the GRP

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1. SCOPE

1.1 Scope. This standard covers standard practices for the application of a four-layer shaft covering system on the body areas of waterborne main propulsion shafting. Material and application requirements are also provided for coatings that are to be applied to waterborne shaft flange assemblies.

2. APPLICABLE DOCUMENTS

2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this standard. This section does not include documents cited in other sections of this standard or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4, or 5 of this standard, whether or not they are listed.

2.2 Government documents.

2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

COMMERCIAL ITEM DESCRIPTIONS

A-A-59875 - Coverings for Waterborne Main Propulsion Shafting on U.S. Naval Surface Ships and Submarines, Anti-Corrosion Polysulfide Material System

(Copies of this document are available online at https://assist.daps.dla.mil/quicksearch/ or https://assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

DEPARTMENT OF DEFENSE SPECIFICATIONS

MIL-PRF-23236 - Paint Coating Systems, Fuel and Salt Water Ballast; (Metric)

MIL-R-23461 - Resin Compound, Thermosetting, Room Temperature Curing, for Metal Coating

(Copies of these documents are available online at https://assist.daps.dla.mil/quicksearch/ or https://assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

2.2.2 Other Government documents, drawings, and publications. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

CODE OF FEDERAL REGULATIONS (CFR)

40 CFR Part 63 - National Emission Standards for Hazardous Air Pollutants for Source Categories

(Copies of this document are available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20401 or online at www.gpoaccess.gov/index.html.)

NAVAL SEA SYSTEMS COMMAND (NAVSEA) PUBLICATIONS

S9086-VD-STM-010/631 - NSTM Chapter 631, Preservation of Ship in Service (Surface Preparation and Painting)

(Copies of this document are available from the Naval Logistics Library, 5450 Carlisle Pike, Mechanicsburg, PA 17055 or online at http://nll.ahf.nmci.navy.mil.)

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2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

AEROSPACE MATERIAL SPECIFICATIONS (AMS)

SAE-AMS3824 - Cloth, Glass, Finished for Resin Laminates

SAE-AMSC9084 - Cloth, Glass, Finished, for Resin Laminates

(Copies of these documents are available from SAE World Headquarters, 400 Commonwealth Drive, Warrendale, PA 15096-0001 or online at www.sae.org.)

2.4 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. DEFINITIONS AND ACRONYMS

3.1 Definitions.

3.1.1 Abrasive-blasting. Abrasive-blasting is an all-inclusive term for the procedure known as sandblasting.

Abrasive materials other than sand are often used and are suitable for shaft surface preparation. Use of sand may not be permitted by some local environmental and safety regulations.

3.1.2 Cure (or curing). The chemical reaction by which thermoset resins change from a liquid to a solid, releasing heat in the process. The resultant mass has characteristic physical properties of a solid. Cure implies more than solidification alone. Cure continues for a period of time after initial solidification and results in the final physical and mechanical properties of the reacted resin.

3.1.3 Elastomeric coating. The second of four layers of the shaft covering system. It is a two-component system, specifically, an epoxy cured with polysulfide that is applied by reaction spray equipment.

3.1.4 Fair. The condition of a flat or curved surface when it is smooth and free of irregularity, unevenness, or abrupt change in curvature. For propulsion shafting, it is the condition in which the sleeve ends blend smoothly into the shaft without abrupt change in thickness.

3.1.5 Glass reinforced plastic (GRP). The fourth of four layers of the shaft covering system that protects the elastomeric components from impact, abrasion, and erosion.

3.1.6 Laminating resin. The mixture of epoxy resin and curing agent used to wet-out the fiberglass fabric in the

GRP.

3.1.7 Peel ply. A nylon or polyester based woven fabric that is used as an expendable surface layer used to produce a prepared surface ready for painting or bonding. The surface of the fabric is not coated with a coupling agent and is removed by the tug of the hand on a loose corner.

3.1.8 Pot life (working life). The length of time that the mixed resin and catalyst is of the workable consistency required for proper application. It is the length of time after the catalyst or hardener has been added, to the point that gelling or thickening of the resin has progressed to the degree it can no longer be applied effectively to the shaft.

3.1.9 Primer. The first of four layers of the shaft covering system. It is a one-component, low-viscosity liquid applied by brush or roller.

3.1.10 Sealing/fairing compound. The third of four layers of the shaft covering system. It is a two-component polysulfide paste applied and distributed with a squeegee to the sleeve end to fair the shaft to the sleeve.

3.1.11 Sleeve. As used herein, a cylindrical tube or band secured to the shaft by shrink-fit and used in way of bearings, coupling covers, and fairwaters.

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3.1.12 SSPC-SP 1. Solvent cleaning – Removal of all detrimental foreign matter such as oil, grease, dirt, soil, salts, drawing and cutting compounds, and other contaminants from steel surfaces by the use of solvents, emulsions, cleaning compounds, steam, or other similar materials and methods which involve a solvent or cleaning action.

3.1.13 SSPC-SP 5. White metal blast cleaning – Removal of all mill scale, rust, rust scale, paint or foreign matter by the use of abrasives propelled through nozzles or by centrifugal wheels. A white metal blast cleaned surface finish is defined as a surface with a gray-white, uniform metallic color, slightly roughened to form a suitable anchor pattern for coatings. The surface, when viewed without magnification, is to be free of all oil, grease, dirt, visible mill scale, rust, corrosion products, oxides, paint, or any other foreign matter.

3.1.14 Tack. The condition of a coated surface that is sticky to the touch.

3.1.15 Thixotropic. A characteristic of resins to which a finely divided (powder) fumed silica has been added, which thickens the resin to the degree that it will not flow or move unless spread by squeegee or brush.

3.1.16 Wet-out. The ability of a resin to “wet” or saturate the reinforcing fibers and completely displace the air in the material fibers. Also, the process of applying resin to reinforcement.

3.2 Acronyms.

3.2.1 AER – Alteration equivalent to repair

3.2.2 AFT – After

3.2.3 AMS – Aerospace material specifications

3.2.4 AMSDL – Acquisition management systems and data requirements control list

3.2.5 CFR – Code of Federal Regulations

3.2.6 CID – Commercial Item Description

3.2.7 CPP – Controllable pitch propeller

3.2.8 CuNi – Copper-nickel

3.2.9 DoD – Department of Defense

3.2.10 DTNSRDC – David Taylor Naval Ship Research and Development Center

3.2.11 EPA – Environmental Protection Agency

3.2.12 ft2 – Square feet

3.2.13 GRP – Glass reinforced plastic

3.2.14 MIL – Military

3.2.15 MS – Maintenance standard

3.2.16 MSDS – Material safety data sheet

3.2.17 NACE – National Association of Corrosion Engineers

3.2.18 NAVSEA – Naval Sea Systems Command

3.2.19 NSTM – Naval Ships’ Technical Manual

3.2.20 r/min – Revolutions per minute

3.2.21 RMC – Regional maintenance center

3.2.22 SAE – Society of Automotive Engineers

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3.2.23 SSPC-SP – Steel Structures Painting Council Surface Preparation

3.2.24 TRS – Technical repair standard

3.2.25 VOC – Volatile organic compound

3.2.26 VPI – Vapor phase inhibitor

4. GENERAL REQUIREMENTS

4.1 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life-cycle costs.

4.2 Personnel. Before being assigned the task of applying the four-layer shaft covering system, personnel shall have the following background and experience:

a. Materials. General knowledge of the characteristics of the materials.

b. Shaft and sleeve preparation. An understanding of the need for the proper shaft and sleeve surface preparation, including abrasive blasting and degreasing, for obtaining acceptable resin adhesive bond.

c. Covering application. The skill required for uniformly applying each of the four layers as described in Appendix A. This shall include the operation of plural component spray equipment.

d. Quality control and inspection. Experience in determining, by visual inspection and the tests specified herein, whether the covering has been properly applied, is void free, and has a continuous adhesive bond to the shaft and sleeve.

4.3 Facilities, tools, and equipment. Facilities shall be required to provide a clean, dry, ambient temperature environment during application of each of the four layers . To ensure the safe and proper application of the shaft covering as described herein, equipment and tools shall be required to perform the tasks of abrasive grit blasting, mixing and applying the shaft preservation materials, and performing specified tests.

4.4 Shaft covering system performance. The applied shaft covering system shall prevent corrosion of waterborne propulsion shafting for a period of 15 years. The individual layers of the four-layer covering system shall meet the following performance requirements:

a. Primer – The primer shall preserve the abrasive-blasted substrate, prepare the substrate for adhesion of the elastomeric coating, and prevent corrosion of the steel shaft should water penetrate the elastomeric coating during service.

b. Elastomeric coating – The elastomeric coating shall not crack under torsional shaft loads.

c. Sealing/fairing compound – The sealing/fairing compound shall prevent cracks from forming at the shaft/sleeve interface. It shall also be used as a filler material for shaft surface irregularities.

d. GRP – The GRP shall protect the first three layers of the covering system from abrasion, erosion, and foreign object contact damage.

5. DETAILED REQUIREMENTS

5.1 Materials. The four layer shaft covering system shall include (in sequential order): 1) primer, 2) elastomeric coating, 3) sealing/fairing compound, and 4) GRP.

NOTE: Except for aircraft carriers, surface ship classes adhering to a dry dock periodicity of 10 years or less may omit the first and second layers (i.e., primer and elastomeric coating, respectively) of the covering system . All four layers of the covering system shall be applied to the waterborne shaft sections of aircraft carriers.

5.1.1 First layer – primer. The first layer of the shaft covering system shall be a one-component, low-viscosity primer for polysulfides in accordance with A-A-59875, Type I.

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5.1.2 Second layer – elastomeric coating. The second layer of the shaft covering system shall be an elastomeric coating, specifically an epoxy cured with polysulfide, in accordance with A-A-59875, Type II. Two different colors shall be used. The first coat shall be gray in accordance with A-A-59875, Type II, Class 1, and the second coat shall be black in accordance with A-A-59875, Type II, Class 1.

5.1.3 Third layer – sealing/fairing compound. The third layer of the shaft covering system shall be a polysulfide sealing/fairing compound in accordance with A-A-59875, Type III that shall be applied to the shaft/sleeve interface. Specifically, the sealant shall be applied at the sleeve end to fair the shaft to the sleeve. The sealant shall also be used as a filler material (see 5.2.2) for allowable pitting.

5.1.4 Fourth layer – GRP. The fourth and final layer of the shaft covering system shall be the GRP.

5.1.4.1 Laminating resins. The laminating resins which are used in the GRP are viscous liquids that cure at room temperature into hard, insoluble, plastics. The resin used shall meet the performance requirements of MIL-R- 23461. Although MIL-R-23461 specifies either of two different types of resin systems (i.e., epoxy or polyester), an epoxy resin shall be used for the shaft covering. The reason for this is that epoxy resins adhere strongly to cured polysulfide. Epoxy resins are mixed as A/B (two-part) kits. The entire kit shall be used to avoid errors in measurement when mixing the epoxy. Pot life of an epoxy resin and associate hardener depends on the ambient temperature, but it is approximately 45 to 60 minutes (see 5.4).

5.1.4.1.1 Cure. Once the hardener or catalyst has been added and thoroughly mixed with the resin, the epoxy will remain liquid for a limited period of time after which it will begin to gel or thicken and become unworkable.

The resin shall cure at room temperature (or according to the manufacturer’s instructions). However, optimum properties can be developed in a shorter time by post curing or heating at moderate elevated temperatures (i.e., 120 to 140 °F). Infrared lamps and strip heaters are convenient sources of heat. Post curing shall be used to obtain optimum cure particularly for coverings applied in cold weather or coverings that shall be put in service as soon as possible.

5.1.4.2 Glass reinforcement. Glass reinforcement shall be woven fiberglass tape with a flat selvage on both edges to prevent fraying, in accordance SAE-AMS3824, style 7500, or SAE-AMSC9084, Type XII A. The surface finish, or sizing, shall be epoxy compatible. The width of tape shall depend on the diameter of the shaft. Four-inch wide tape shall be used for shaft diameters 8 inches and less. Six-inch wide tape shall be used for shaft diameters greater than 8 inches.

NOTE: The tape widths outlined above are specified for ease of application. Wider tapes are more difficult to apply and attain a quality finished product. The skill and experience of the laminating team is the limiting factor for the width of tape used.

5.2 Auxiliary materials. Additional material requirements are as follows:

5.2.1 Thixotropic filler (thickening agent). The addition of a small amount (2 to 4 percent) of a thixotropic filler (supplied by resin vendor), or other commercial source, to the epoxy laminating resin shall be used to minimize or eliminate resin drainage from the GRP if applied to a stationary shaft.

5.2.2 Fairing compound for shaft. Irregular surfaces (i.e., allowable pitting and/or approved excavations) shall be filled and smoothed using fairing/sealing compound prior to application of the elastomeric coating, and allowed to cure.

5.2.3 Coating for flange couplings. All waterborne shaft flange assemblies housed within rotating coupling covers shall receive the elastomeric coating (i.e., second layer) described herein. The same shall apply to all new acquisition spare shafting assets. Additionally, all waterborne flange assemblies previously coated with any alternative paint system shall likewise receive the elastomeric coating (i.e., second layer) outlined herein upon renewal/overhaul of the shaft assembly (see Appendix A).

NOTE: Some older ship classes do not possess rotating coupling covers in way of waterborne shaft flange assemblies (i.e., CVN 65 and LPD 7 Class). Instead, their waterborne flange assemblies possess either two (2) coats of an epoxy conforming to MIL-PRF-23236, Class 2 or a resin formulation. For these particular ship classes, upon refurbishment of their respective waterborne shaft sections, the subject flange assemblies shall receive the elastomeric coating (i.e., second layer) specified herein prior to application of either the epoxy or resin formulation.

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NOTE: The AFT flanges of controllable pitch propeller (CPP) shafts are clad in Inconel by design. Therefore, they do not require the additional preservation as identified in 5.2.3.

5.3 Estimation and preparation of the basic materials required. This section covers the calculation of the amount of primer, elastomeric coating, sealing/fairing compound, fiberglass tape, and laminating resin required for the four-layer shaft covering system and their preparation for application.

5.3.1 First layer – primer. The primer coverage will vary depending on the application method. For estimation purposes, allow 1 gallon for every 60 linear feet of shafting.

5.3.2 Second layer – elastomeric coating. At a thickness of 10 mils (0.010 of an inch), the coverage is approximately 160 ft2/gallon for an approximate shaft diameter of 30 inches. That is, at a 10-mil thickness, one gallon should cover about 25 linear feet of shafting. At a thickness of 20 mils, the coverage is approximately 80 ft2/gallons, meaning one gallon should cover about 12 linear feet of shafting. The amount of elastomeric coating remaining in the hose shall be accounted for when determining the amount of elastomeric coating required.

5.3.3 Third layer – sealing/fairing compound. The sealing/fairing compound is a two-part polysulfide that shall be used to fair the shaft to the sleeve at subject interface. Sealant shall be applied only to the sleeve end and adjacent shaft in a swath no more than 12 inches wide. The application thickness shall be approximately 20 mils (0.020 of an inch), which corresponds to approximately 1.75 ounces/ft2. Thus, the ounces of sealant required to cover the 1 linear foot of sleeve end (which includes the shaft and sleeve) can be estimated as:

Ounces of sealant/foot = (1.75) × (shaft circumference in inches)/12.

For example, if the shaft is 72 inches in circumference, sealant coverage will require approximately 10.5 ounces per linear foot. However, since sealant is used to fair the shaft to the sleeve, it is thicker at the sleeve end. In addition, a significant amount of the sealant will remain in the mixing container. Therefore, about 1 pound of mixed sealant will be required to fair each sleeve end. Partial kits can be mixed if necessary by following the instructions in the technical data sheets. This shall require weighing the individual components.

5.3.4 Fourth layer – GRP.

5.3.4.1 Laminating resin. Estimate the total amount of epoxy laminating resin (including hardener) required by using 1 gallon of resin for every 81.5 square feet of tape per layer times five layers (four layers of tape and the finish coat). The 81.5 square feet per gallon is based on resin requirements per layer of fiberglass tape to provide thorough wet-out. The total amount of resin can also be estimated on a mass basis by multiplying the total mass of tape (all four plies, as determined in 5.3.4.2.2) by a factor of 2. Using a factor of 2 will provide a sufficient excess of mixed resin for coating the shaft and thoroughly wetting-out the fiberglass tape.

5.3.4.1.1 Example of epoxy laminating resin calculation based on weight. Four 41-foot lengths of 6-inch tape would have a mass of approximately 5.5 pounds.

Total mass of resin = 5.5 pounds × 2 = 11 pounds.

WARNING: The resin and hardener shall not be mixed together until immediately prior to use, since the mixture will have a limited working life.

5.3.4.1.2 Preparation of epoxy laminating resins. Since epoxy resins have limited pot or working life, especially in warm temperatures, separate batches of resin may need to be prepared for each of the four layers of glass tape. It is recommend that epoxy laminating resins be selected that are available in kits of approximately one gallon. This eliminates the need for weighing out resin-to-hardener ratios, eliminates the potential errors that can occur during weighing of the resin and hardener, eliminates mass-effect on pot life, and provides a convenient batch size.

NOTE: Mass-effect accelerates curing which results in reduced pot life. Resin is a poor heat conductor, so with larger resin volumes, more heat is produced, resulting in higher curing temperatures that further accelerates the chemical reaction.

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5.3.4.1.3 Fillers. Resin flow from the freshly applied GRP shall be minimized or eliminated by assuring the proper resin viscosity. Resin viscosity can be increased by the addition of a thixotropic filler material (see 5.2.1).

The addition of thixotropic filler is typically required for shafts that are stationary during application of the GRP to keep the resin from dripping off of the GRP tape during both application and cure. The amount of filler added to the resin shall be determined based upon prior experience, trial, or the recommendation of the resin manufacturer.

Particular care shall be taken to avoid beating air into the resin while mixing in the thixotropic filler. The addition of the filler may obscure visual inspection for voids and trapped air. Fillers shall not be used on shafts which are rotated during application and cure.

5.3.4.2 Fiberglass tape. The length of fiberglass tape shall be calculated using the following equation:

3.5 × D × H L=

W

L = Length of tape required for each ply (feet)

D = Diameter of the shaft (inches)

H = Length of the section of straight run of shaft to be covered (feet)

W = Width of the fiberglass tape (inches)

NOTE: The factor 3.5 in the above equation is used instead of the extract factor (n = 3.14) to allow for some excess tape and some overwrap at terminations.

5.3.4.2.1 Example of calculation for fiberglass tape. Calculate the length of 6-inch wide glass tape required for each ply of a GRP for a 10-foot long section of shafting measuring 7 inches in diameter.

3.5 × D × H D = 7 inches

H = 10 feet

W = 6 inches

L= W ft in ftin 83.40

1075.3

The total length of tape required for the four plies is equal to four times the length of a single ply as calculated above.

5.3.4.2.2 Preparation of fiberglass tape. Determine the amount of tape on each roll furnished to be sure there is sufficient material for accomplishing the task. If the mass of the tape is used to determine the amount of resin required (see 5.3.4.1.1), determine the total weight of the GRP tape required to apply four layers of tape to the shaft.

NOTE: Care shall be taken to keep the tape free of dirt, dust and other contaminants. Tape that has been exposed to water, solvents, and lubricants is not useable and shall be discarded. The glass tape shall remain wrapped in plastic until such time that it is used.

5.4 Safety precautions.

5.4.1 General. Caution shall be observed when handling any chemicals or solvents. The application of the GRP shaft covering is no exception. When applying the covering, the following general precautions shall be observed:

a. The working area shall be properly and adequately ventilated to draw fumes away from the worker.

b. Avoid direct contact with the solvents, resins, and associated hardeners and catalysts.

c. Keep chemical containers clearly labeled, tightly covered when not in use, and stored in a cool, dry area.

d. Do not work near hot surfaces or open flames. Do not smoke on the job or when handling chemicals.

e. Review the manufacturer’s MSDS for the specific resin system to be used.

f. For further guidance on related safety procedures and equipment, refer to S9086-VD-STM-010/631.

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5.4.2 Specific precautions. The following specific precautions shall be observed:

a. Wear disposable plastic gloves, protective clothing, and goggles. Use barrier cream on exposed skin which may come in contact with resin or hardeners.

b. Wear a dust respirator when handling the thixotropic filler.

c. Avoid contact of resins and associated chemicals with eyes, skin, or clothing. Absorption through the skin may be harmful. In case of contact with the skin, immediately wash with soap and water and flush with plenty of water for at least 15 minutes. If the eyes are involved, immediately flush with water for at least 15 minutes.

Medical attention shall be obtained as soon as possible.

NOTE: Some people may develop an allergic reaction to epoxy resin with extended or frequent skin contact.

d. Avoid prolonged or repeated breathing of vapors. If ventilation is not adequate, wear an organic vapor respirator.

e. If clothes or shoes become contaminated, remove at once and clean thoroughly before reuse.

f. Always wash exposed skin areas thoroughly after completing the job.

5.5 Facility requirements. In general, the shaft covering system is typically applied in two separate facilities.

5.5.1 Shaft preparation, primer application, and elastomeric coating application. The “blast and coat” facility shall provide the equipment to abrasive blast the shaft steel and sleeve to NACE SSPC-SP 5 white metal finish (see 3.1.12). The first layer (primer) and second layer (elastomeric coating) shall be applied in the blast and coat facility.

5.5.1.1 Ventilation. The blast and coat facility shall follow all local ventilation requirements during application of the primer and elastomeric coating.

5.5.1.2 Reaction spray equipment. Plural component reaction spray equipment shall be used for application of the elastomeric coating. Once mixed, the two components of the elastomeric coating start to cure. It is permissible to mix and apply by brush, but in most cases this will require several batches due to the short working life.

Thinning the resin with solvent and spraying with conventional equipment is strictly prohibited.

5.5.2 Third and fourth layers – sealing/fairing compound and GRP application. After the elastomeric coating cures, the shaft sections shall be moved to the machine shop. The third layer (sealing/fairing compound) and fourth layer (GRP) shall be applied in the machine shop.

5.5.2.1 Lathe. The machine shop shall have a lathe large enough to accommodate a shaft section.

5.5.2.2 Temperature. During application of the GRP, the ideal temperature of the shaft and the immediate environment should be about 73 °F. Application of the GRP shall not be attempted at temperatures below 60 °F (since both cure of the resin and wet out of the fiberglass will be adversely affected) unless a suitable heat controllable enclosure is used which enables all areas of the shaft to be covered and the covering to be maintained above 60 °F. At higher temperatures (for example, 80 to 90 °F) the gel time (pot life or working life) of the resin will be significantly reduced. Per MIL-R-23461, the resin system may have a gel time of 30 minutes to 2 hours at 73 °F and a minimum of 18 minutes at 90 °F. The manufacturer’s instructions shall be consulted for gel time or working life of the specific resin system used. The resin shall not be applied beyond the gel time limits specified by the manufacturer for the resin system used.

5.6 Application instructions. Detailed procedures for applying the four-layer shaft covering system shall be in accordance with Appendix A.

5.7 Inspection and repair. Detailed inspection and repair procedures for the four-layer shaft covering system shall be in accordance with Appendix B.

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6. NOTES

(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)

6.1 Intended use. This standard describes detailed instructions for the preparation and drydock repair of the four-layer covering system for waterborne propulsion shafting. Application of the four layers is to take place in a clean, dry environment with the appropriate temperature range.

6.2 Acquisition requirements. Acquisition documents should specify the following:

a. Title, number, and date of this standard.

6.3 Subject term (key word) listing.

Epoxy

Epoxy polysulfide coating

Polysulfide sealant

Woven fiberglass

6.4 Changes from previous issue. Marginal notations are not used in this revision to identify changes with respect to the previous issue due to the extent of the changes.

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APPENDIX A

PROCEDURE FOR APPLYING THE FOUR-LAYER SHAFT COVERING SYSTEM

A.1 SCOPE

A.1.1 Scope. This appendix details the procedure for applying the four-layer shaft covering system outlined within this standard. This appendix is a mandatory part of this standard. The information contained herein is intended for compliance.

A.1.2 General description. After proper shaft surface preparation (see figure A-1), a coat of primer shall be applied uniformly to the shaft (see figure A-2). The primer dries in about 30 minutes. After the shaft is dry, the two coats of elastomeric coating shall be applied (see figure A-4), ideally by plural component reaction spray. After a minimum of 24 hours in the blast and coat facility, the shaft section shall be wrapped and moved to the area for application of sealing/fairing compound and GRP . While the shaft is turning, sealant shall be applied to the sleeve ends (see figure A-1) with a squeegee (or other similar application tool selected by the trades personnel).

Sealing/fairing compound shall fair the shaft, and cover the sleeve up to the point where GRP is applied. The sealant shall also be applied about six inches down the shaft. After a minimum of 2 hours, the GRP shall be applied (see A.3.2.4). The first ply of glass tape is then wound spirally on the shaft, butting the edges. After working out entrapped air and ensuring that the glass tape is wet-out properly, a coat of resin shall be applied over this ply. A second ply of glass tape shall then be wound on the shaft, reversing the direction of the spiral wrap. This process shall be continued until four plies of tape have been applied. Safety precautions (see 5.4) shall be observed in the handling and application of these materials.

NOTE: Accept for aircraft carriers, surface ship classes adhering to a dry dock periodicity of 10 years or less may omit the first and second layers (i.e., primer and elastomeric coating, respectively) of the covering system. All four layers of the covering system shall be applied to the waterborne shaft sections of aircraft carriers.

A.2 APPLICABLE DOCUMENTS

A.2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this appendix. This section does not include documents cited in other sections of this appendix or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4, or 5 of this appendix, whether or not they are listed.

A.2.2 Government documents.

A.2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this appendix to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

DEPARTMENT OF DEFENSE SPECIFICATIONS

MIL-PRF-121 - Greaseproof, Waterproof, Flexible, Heat-Sealable Barrier Materials

MIL-PRF-680 - Degreasing Solvent

MIL-PRF-23236 - Paint Coating Systems, Fuel and Salt Water Ballast; (Metric)

MIL-DTL-24441 - General Specification for Epoxy-Polyamide Paint

MIL-PRF-24647 - Paint System, Anticorrosive and Antifouling, Ship Hull

(Copies of these documents are available online at https://assist.daps.dla.mil/quicksearch/ or https://assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

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A.2.2.2 Other Government documents, drawings, and publications. The following other Government documents, drawings, and publications form a part of this appendix to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

NAVAL SEA SYSTEMS COMMAND (NAVSEA) DRAWINGS

803-2145807 - Standard Drawing for Propulsion Shafting & Components

(Copies of this document are available from the Commander, Naval Sea Systems Command, ATTN: SEA 05S, 1333 Isaac Hull Avenue, SE, Stop 5160, Washington Navy Yard DC 20376-5160 or by email at CommandStandards@navy.mil.)

NAVAL SEA SYSTEMS COMMAND (NAVSEA) PUBLICATIONS

S9086-HM-STM-010/243 - NSTM Chapter 243, Propulsion Shafting

S9086-VD-STM-010/631 - NSTM Chapter 631, Preservation of Ship in Service (Surface Preparation and Painting)

(Copies of these documents are available from the Naval Logistics Library, 5450 Carlisle Pike, Mechanicsburg, PA 17055 or online at http://nll.ahf.nmci.navy.mil.)

A.2.2.3 Non-Government publications. The following documents form a part of this appendix to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

NACE INTERNATIONAL

SSPC-SP 1 - Solvent Cleaning

SSPC-SP 5 - Joint Surface Preparation Standard: White Metal Blast Cleaning

(Copies of this document are available from NACE International, 1440 South Creek Drive, Houston, TX 77084-4906 or online at www.nace.org.)

A.2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

A.3 PROCEDURE

A.3.1 Shaft assembly preparations.

A.3.1.1 Preparation of shaft body areas and interfacing sleeve end prep areas. Shaft body surfaces and corresponding sleeve end prep areas shall be prepared immediately prior to application of the shaft covering in accordance with the following procedures to ensure a maximum degree of adhesion:

a. Remove any pre-existing covering, including GRP, fairing compound, and corrosion preventive paint/primer, as applicable, on the shaft body and sleeve end prep areas by mechanical means. A disc sander, Dremel tool (or equal), or suitable abrasive cutting tool may be used to score the GRP. The GRP is to then be removed via machining with the shaft in a lathe using a blunted (bull nose) machine tool. The fairing compound can be scored with a chisel or screwdriver and chipped or peeled away as applicable. All paint/primer is to be removed utilizing a disc sander, flapper wheel, and/or wire brush.

NOTE: Water/abrasive blasting is also an acceptable method to remove any pre-existing covering. Regardless of the process utilized, exercise extreme caution not to damage the underlying shaft surface when accomplishing subject task.

b. Remove any oil or grease from the flange surfaces by solvent cleaning (using petroleum distillate type solvent in accordance with MIL-PRF-680, Type II or other solvent that provides suitable cleaning and degreasing capability without leaving a residue) in accordance with SSPC-SP 1 (see 3.1.12). Solvents shall not be ozone depleting types and shall be acceptable under local, State and Federal regulations, as required.

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c. Mask off the areas on the sleeve(s) that will not receive the covering system. This is typically about 6 inches from the sleeve end (see figure A-1).

d. Metal shaft body and sleeve end prep surfaces to be covered shall be abrasive blasted in accordance with SSPC-SP 5 (see 3.1.13) with clean abrasive grit to achieve a 3-mil average profile.

FIGURE A-1. A typical shaft and sleeve configuration, prepped for the shaft covering.

e. Wash blasted surfaces with solvent, as required in A.3.1.1.b, after abrasive blasting; assure that no residue remains.

f. Pitting of the shaft steel shall be assessed and addressed as specified in the applicable shafting technical repair standard (TRS) or maintenance standard (MS) and/or S9086-HM-STM-010/243. Irregular surfaces shall be filled and smoothed as per 5.2.2. It is recommended that this effort be accomplished following application and cure of the first layer - primer. Subject areas shall be smoothed/blended to adjacent shaft surfaces with a squeegee.

g. Apply the primer (see A.3.2.1) as soon as possible (within 8 hours) after the abrasive blasting. Freshly blasted and cleaned surfaces shall be wrapped with plastic film or VPI paper in accordance with MIL-PRF-121, Type I, Grade A, Class 2 in extending the hold time up to a maximum of 24 hours prior to commencing primer application. If primer application cannot be started within either 8 or 24 hours, as applicable, or if there is evidence of oxidation, re-abrasive blast the shaft as outlined above.

NOTE: For those shaft sections not receiving the primer or elastomeric coating application (based upon their drydocking periodicities accordingly), wrap the blasted and cleaned surfaces with the plastic film or VPI paper in accordance with MIL-PRF-121, Type I, Grade A, Class 2 to prevent oxidation from occurring during transit from the blast and coat facility to the shop floor.

A.3.1.2 Preparation of waterborne shaft flange assemblies. Surface preparation for waterborne shaft flange assemblies will vary slightly based upon their respective configurations identified previously in 5.2.3. Regardless, the following does not apply to the AFT flange of CPP propeller shafts.

A.3.1.2.1 Shaft flanges enclosed within rotating coupling covers. Prepare the flanges for coating application as follows:

a. For in-service waterborne shafting or spare waterborne shaft assets whose flanges have not been previously coated, remove any residual preservative from the mating flange assemblies, extending up to respective sleeve ends by chemical/solvent cleaning with cloths and/or bristle brushes, or mechanical means such as abrasive blasting.

ABRASIVE BLAST

MASK THIS AREA TO PREVENT

DAMAGE DURING ABRASIVE

BLAST

SLEEVE

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b. Remove any oil or grease from the flange surfaces by solvent cleaning (using petroleum distillate type solvent in accordance with MIL-PRF-680, Type II or other solvent that provides suitable cleaning and degreasing capability without leaving a residue) in accordance with SSPC-SP 1 (see 3.1.12). Solvents shall not be ozone depleting types and shall be acceptable under local, State and Federal regulations, as required.

c. Mask off the coupling cover sleeve(s) as well as the flange bolt holes, bolt head/nut washer faces, and mating flange faces.

d. Abrasive blast the exposed metal flange surfaces to SSPC-SP 5 (see 3.1.13).

e. Upon completion of abrasive blasting, solvent clean the blasted flange surfaces in…