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Powder will absorb moisture if the air in the storage area is above
60% relative humidity. This will cause it to clump together, resist fluidization
and flow poorly. In most cases, the clumping can be eliminated
by a combination of stirring and fluidizing for a few minutes.
Still, it is better to store powder at a range of 40 to 60% RH.
If powder is stored in a controlled environment within these parameters,
it will normally remain stable for at least one year. Storage in a
controlled environment will provide more consistent behavior of the
powder during application.
To avoid problems with powder materials, storage areas should be
controlled as follows:
• Control temperature to 80 °F (27 °C) or less.
• Control the relative humidity between 40 and 60% RH.
• Rotate stored powder so that it is not kept in storage for extended
periods of time. First in, first out.
• Avoid leaving containers of powder open on the shop floor where
the powder can easily pick up moisture and dirt.
• Precondition the powder before spraying by fluidizing it for a
few minutes prior to application.
Like many of the recommendations in this book, these precautions
are not absolutely necessary to the application of powder. However,
following them will produce the best possible results with the least
possible labor. Proper storage and a little patience to achieve correct
fluidization will help contribute to consistent results.
60% relative humidity. This will cause it to clump together, resist fluidization
and flow poorly. In most cases, the clumping can be eliminated
by a combination of stirring and fluidizing for a few minutes.
Still, it is better to store powder at a range of 40 to 60% RH.
If powder is stored in a controlled environment within these parameters,
it will normally remain stable for at least one year. Storage in a
controlled environment will provide more consistent behavior of the
powder during application.
To avoid problems with powder materials, storage areas should be
controlled as follows:
• Control temperature to 80 °F (27 °C) or less.
• Control the relative humidity between 40 and 60% RH.
• Rotate stored powder so that it is not kept in storage for extended
periods of time. First in, first out.
• Avoid leaving containers of powder open on the shop floor where
the powder can easily pick up moisture and dirt.
• Precondition the powder before spraying by fluidizing it for a
few minutes prior to application.
Like many of the recommendations in this book, these precautions
are not absolutely necessary to the application of powder. However,
following them will produce the best possible results with the least
possible labor. Proper storage and a little patience to achieve correct
fluidization will help contribute to consistent results.
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