Reports.
3.9
MIXING AND APPLICATION OF SEALANT AND COATING SYSTEM
3.9.1
Preparation of Sealant and Coating Materials for Application
Each of the different products, sealant, primer, intermediate, and topcoat,
is a two-component material supplied in separate containers.
3.9.1.1
Mixing
Mix in accordance with manufacturer's instructions, which may differ for
each product. Do not mix partial kits, or alter mix ratios. Mix materials
in same temperature and humidity conditions specified in article entitled
"Delivery and Storage." Allow mixed material to stand for the required
induction time based on its temperature.
3.9.1.2
Pot Life
Apply mixed products within stated pot life for each product. Stop
applying when material becomes difficult to apply in a smooth, uniform wet
film. Do not add solvent to extend pot life. Add all required solvent at
time of mixing. Pot life is based on standard conditions at 21 degrees C
70 degrees F and 50 percent relative humidity. For every 10 degrees C 18
degrees F rise in temperature, pot life is reduced by approximately half,
and for every 10 degrees C 18 degrees F drop, it is approximately doubled.
Usable pot life depends on the temperature of the material at the time of
mixing and the sustained temperature at the time of application. Other
factors such as the shape of the container and volume of mixed material may
also affect pot life. In hot climates, precooling or exterior icing of
components for at least 24 hours to a minimum of 10 degrees C 50 degrees F
will extend pot life. Following are approximate pot life times:
Sealant
As specified by manufacturer
Epoxy Primer and Intermediate Coat Materials
4 hours
3.9.1.3
Application Conditions and Recoat Windows
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NOTE: These requirements are provided in an attempt
to prevent the significant number of intercoat
delamination failures that are frequently found on
industrial structures. The very strict requirements
on application conditions and recoat windows may
require work during abnormal hours, including
weekends. Contractor work hours should allow for
such during coating application.
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NOTE: Cold-weather application is not covered by
this specification. If a project is designed for
coating in cold weather, then the enclosure and
heating requirements may be significant. It is not
intended that contractors be forced to apply
coatings in cold weather, however, the underlying
premise is that coatings must be applied within the
specified temperature ranges. A cold-weather
specification should not be used to simply save
SECTION 09972
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