Surface World May 2019 Surface World May 2019 | Page 40

TESTING & MEASUREMENT
How many mils is your coating?
Instantaneous handheld
coating thickness gauges
that can be operated by
virtually any technician
deliver lab-quality readings
even on curved and
complex surfaces.
From the job shop to the robotic assembly
floor, it is vital that the product be made
well and correctly coated for protection,
aesthetics, and performance.
So, industries like automotive, aerospace,
and those utilising plating, anodising,
powder coating or other coatings need
accurate coating thickness measurement.
This is particularly important when the
coatings play a critical role in preventing
the corrosion or wear of metal substrates.
Properly applied coatings, with thickness
measured in mils (.001 inch) or microns
(.001 mm), are also essential for paint/
coatings contractors and companies
that coat a wide range of building and
functional surfaces, including pipe.
Accurate application and coating thickness
measurement, in fact, are crucial to avoid
coating breaches leading to corrosion of the
underlying substrate. This can help to prevent
leaks and other safety issues in a wide range
of industries.
However, until recently conducting frequent
laboratory-quality coating thickness tests
throughout the manufacturing process or
in the field has been difficult. Traditionally,
this required meticulous sampling and
preparation, as well as taking the sample
to the lab for evaluation. Although portable
coating thickness gauges are not new,
most fail to provide the accuracy, speed,
or simplicity required for anyone to conduct
quick checks as needed on the production
line or in the field.
Fortunately, handheld devices are now
available that allow personnel to easily and
quickly perform lab-quality coating thickness
measurements. Some options offer instant
coating thickness measurement of almost
any non-magnetic coating on both ferrous
(magnetic) and non-ferrous (non-magnetic)
substrates. This is possible using only one
hand, even on curved and complex surfaces.
By simplifying the process, industrial facilities
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and paint/coatings contractors and
companies can increase the quality of
their products and services from start
to finish while optimising cost.
The Many Benefi ts of
Coating Thickness Readings
Coating thickness directly affects product
quality, whether for automotive paint,
electroplating, anodising, or a wide range
of other coating applications. For example,
checking the paint coating consistency on
a vehicle not only provides a product with a
superior finish, but can also offer essential
data about the consistency of the paint when
it is wet.
“Incorrect paint consistency can affect drying
times or eventual flaking of the paint film,”
says John Bogart, Managing Director of Kett
US, a manufacturer of a full range of coating
thickness testers. “Too little paint coating and
you are left with cosmetic issues in opacity,
and protective issues like corrosion, wear,
and exposure. Checking coating thickness
can also tell if auto body work has been
done on a used car, which can help the
customer or dealer make a good decision
on pricing.”
When specificity and adhesion matter in
anodising and electroplating, a coating
thickness gauge should be able to read the
thickness of the coating to the most minute
measurement. This can play a major factor
in preventing corrosion while optimising
the process by eliminating any excess use
of the expensive plating product.
Another way a coating thickness gauge
can make a significant impact is in testing
anti-corrosion pipe coatings to find weak
spots, where the coating is too thin and
a breach of the coating could make the
substrate susceptible to corrosion, according
to Bogart.
“Knowing about these trouble spots can
prevent a disaster well before it occurs,” he
says. “This might involve petrochemical pipes
in a facility, water pipes in a home or office,
or even the piping and tubing in an engine.”
“A nondestructive gauge is a perfect way to
ensure that the pipe’s protective coating has
not been applied too thinly or become so over
time,” he adds. “Excessively thin coatings are
more likely to be chipped or breached, which
can lead to corrosion promoters like water
or oxygen getting under the coating and
accelerating corrosion in the substrate.”
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