for instructions not found in Section 09964.
Metallizing systems will provide excellent
atmospheric corrosion protection for extended
periods without sealing or painting. However,
painting is recommended to extend the life of the
metallic coating, and in some cases, to achieve a
desired appearance. Painting systems found in
Section 09964 may be used to seal and paint the
metallized surface. It is often convenient to paint
metallized surfaces with identical paint systems
employed on adjacent or contacting surfaces that
have not been metallized. Paint systems No. 3, 4,
and 5-D are suitable for sealing atmospherically
exposed portions of partially immersed items such as
tainter gates. Systems 13, 14, and a modified
version of system 21 where it is topcoated with SSPC
Paint 34, are recommended for items only exposed to
the atmosphere. Paint systems No. 14 and SSPC Paint
34 are available in safety colors. Paint system 13
provides an aluminum finish. Other coating systems
found in Section 09964 are not recommended.
When used for high temperature atmospheric
applications system 8-A should not be sealed.
Sealing and painting of the metallized surfaces
intended for immersion is generally recommended to
extend the life of the metallic coating except that
aluminum coatings to be immersed in salt water
should not be painted. Paint systems No. 3, 4, 5-D,
and 21 are recommended for immersion applications.
When used as a zebra mussel antifoulant, system
6-Z-A should not be sealed or painted.
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All sealer and paint materials shall conform to the requirements of Section
09964 PAINTING: HYDRAULIC STRUCTURES.
2.3
ABRASIVE MEDIA
The abrasive blast media shall be a hard angular type capable of producing
the specified surface profile listed in paragraph Abrasive Blasting. The
blast media shall be steel grit, silicon carbide, aluminum oxide, garnet,
coal slag, or iron oxide. New steel grit shall conform to the requirements
of SSPC AB 3 including paragraph 4.3.3.2 Steel Grit. Steel grit hardness
shall be Rockwell C of 51 or greater. Recycled steel grit shall conform to
the requirements of SSPC AB 2 and shall at no time contain greater than 15
per cent round or half-round particles when viewed under a 10X microscope
or magnifying glass. Garnet abrasive shall conform to the requirements of
SSPC AB 1, Type 1, Class A, and shall be an appropriate grade to produce
the specified blast profile. Iron oxide abrasive shall be a commercial
specular hematite material. Coal slag abrasive shall conform to the
requirements of SSPC AB 1, Type 2, Class A, and shall be an appropriate
grade to produce the specified blast profile. Silicon carbide and aluminum
oxide abrasives shall be commercially pure materials of the appropriate
gradation to produce the specified blast profile.
SECTION 09971A
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