MIL-STD-2199A APPENDIX A
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 accordance with step b above.
f. Begin flange preservation (see A.3.3.1) 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 coating 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 flange as outlined above.
A.3.1.2.2 Coated flanges normally exposed to seawater. Prepare the flanges for coating application as follows:
a. Remove all pre-existing covering, including GRP and epoxy, 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 with a disc sander after being scored. Remove the epoxy 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.
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 NACE 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 flange bolt holes, bolt head/nut washer faces, and mating flange faces. If the shaft is configured with independent fairwater sleeve(s), mask-off the sleeve(s) as shown on figure A-1.
d. Abrasive blast the exposed metal flange surfaces and fairwater sleeve end prep area(s), as applicable, to
NACE SSPC-SP 5 (see 3.1.13).
e. Upon completion of abrasive blasting, solvent clean the blasted surfaces in accordance with step b above. f. Begin flange preservation (see A.3.3.2) 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 coating 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 flange as outlined above.
A.3.1.3 Preparation of the shaft-to-sleeve end interfaces.
A.3.1.3.1 Preserving the sleeve end prep area. Experience has shown that application of the shaft covering is most critical in the sleeve end prep area, specifically at the interface of the sleeve end and the shaft. Most historical shaft failures were found to initiate in this area, which is thought to be due to cracks which form in the rigid fairing compound due to shaft torsion. For this reason, an elastomeric coating and polysulfide sealing/fairing compound were selected for application in shaft preservation. Specific focus shall be directed at the sleeve end during all aspects of the shaft coating. Abrasive blast and subsequent primer, coating, and sealant application shall be done with particular care at the shaft-to-sleeve interface.
A.3.1.3.2 Sleeve masking precautions. The four-layer system shaft coating system bridges the shaft and sleeve. It covers the entire shaft body area(s) and extends approximately 5 inches up each interfacing sleeve end. If the materials applied to the shaft sleeve(s) during steps A.3.1.1.c and A.3.1.2.2.c to mask off areas of the sleeve(s) were damaged during blasting, they shall be replaced prior to commencing application of the covering system.
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