Method and Results
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Method:
After thermal cycling, all ten test panels
were placed in a Seawater Spray (Fog) Chamber, ASTM B117, for
500 hours (3 weeks). The Salt Water Spray Test is considered
to be the toughest weathering test that a coating can undergo.
The chamber was operated in accordance with the procedures set
forth in ASTM B117, except actual sea water was used in place
of standard salt water. This provides a more natural and realistic
scientific test. Salt spray is a natural phenomenon in seaside
and seagoing environments and is also of interest to automobile
owners in northern climates where the roads are salted in the
winter to melt ice. To simulate these conditions, seawater is
atomized with a special device and allowed to condense in an
even manner on the surface of the test panels. It combines the
corrosive effects of sea water with the oxidizing effects of
oxygen dissolved from the air by the water droplets. Additionally,
it provides an erosive wash condensation and flow over the coating
surface. Keep in mind, these panels have already been X-scribed,
been through 300 hours in the Weatherometer, and Thermally cycled
as described earlier. The length of exposure for the Seawater
Spray Test is specified by the United States Navy’s standards,
which is 300 hours below deck and 500 hours above deck. |
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Results: The Rust Bullet® panel (number 2), the Rust-oleum® Cold Galvanizing Compound panel (number 5), the Wasser® Brand System panel (number 6), and the POR-15® System panel (number 8), exhibited corrosion along the scribe lines with undercutting of less than 3/16 of an inch. The Rust-oleum® Rusty Metal Primer panel (number 1), the Rust-oleum® Rust Reformer panel (number 3), the Zynolyte Urethane with Zinc-Chromate Primer panel (number 4), the Naval Jelly® Rust Neutralizer panel (number 7), and the Hammerite® Rust Cap panel (number 9), exhibited coating failure over the entire surface of each panel. These panels were considered complete failures and were eliminated from further testing. The uncoated control panel (number 10) was so severely corroded it was of no further value and was also eliminated. Printed from National
Testing Standards, Inc., Report: Method: After thermal cycling
all ten test panels were placed in a salt fog/spray chamber for
500 hours (3 weeks). The chamber was operated in accordance with
the procedures set forth in ASTM B-117 except actual sea water
was used in place of standard salt water. |
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