MIL-HDBK-1110
11.4.2.7 Blistering to Substrate. The blisters that arise from
the substrate may be broken or unbroken. If broken, they may
lead to peeling and be hard to identify. Blistering to wood or
concrete/masonry substrates may be caused by moisture in the
substrate.
11.4.2.8 Peeling. Peeling is the disbanding of stressed
coatings from the substrate in sheets. It is generally preceded
by cracking or blistering.
11.4.2.9 Flaking (Scaling). Flaking or scaling is similar to
peeling, except the coating is lost in smaller pieces. Flaking
of aged alkyd coatings occurs commonly on wood.
11.4.3
Examples of Using Decision Trees. The decision trees 1
and 2 (Figures 24 and 25) can best be understood by using
examples.
11.4.3.1 Example of Surface Defect. This example is a surface
defect that does not penetrate the finish coat so that use of
decision tree 1 is required. We start with Question 1, "Does
detergent washing remove the defect?" In our example, the answer
is "Yes," so we proceed to Question 2, "Does wiping with a dry
felt cloth remove defect?" This time the answer is "No," so we
proceed to Question 3, "Does defect disappear when treated with
household bleach?" In our example, the answer is "Yes," so we
have tentatively identified the defect as "Answer 2" mildew.
11.4.3.2 Example of a Film Defect. This example is a defect
that penetrates the finish coat so that use of decision tree 2 is
required. We start with Question 10, "Do oval voids that
originate at time of coating application expose an undercoat or
the structural substrate?" In our example, the answer is "No,"
so we proceed to Question 11, "Does the failure expose only an
undercoat?" This time the answer is "Yes," so we proceed to
Question 12, "Which best describes the failure?" In our example,
the answer is "Peeling topcoat to expose undercoat," so we have
tentatively identified the defect as "Answer 17" intercoat
delamination.
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