Technical data

2.7 GENERAL OVERALL CHEMICAL REMOVAL
PROCEDURES.
Chemical removal of organic finish systems shall be per-
formed in accordance with the following sequential steps:
Chemical removers are toxic to skin, eyes, and
respiratory tract. Skin and eye protection re-
quired. Contact Bioenvironmental Engineering
for determination of need for and selection of
proper respiratory protection.
a. Ensure that all facility safety, health, and disposal
requirements and all personnel safety and health re-
quirements in Paragraph 2.2 step a and step b are met.
b. Determine the type of organic finish to be removed in
accordance with Paragraph 2.2 step c. Select and obtain
the proper chemical remover for the finish system
involved in accordance with Paragraph 2.6.2, Paragraph
2.6.3, or Paragraph 2.6.4.
c. Ensure that the removal operation has been properly
planned and that all personnel understand the operation
as required by Paragraph 2.2 step d.
d. Ensure that the aircraft, equipment or component has
been properly cleaned, dried, and masked in accordance
with Paragraph 2.3 through Paragraph 2.3.2.1 step i.
e. Ensure that the aircraft, equipment, or component has a
surface temperature within the specified range and is
located within a covered facility having an ambient air
temperature within the specified range defined in Para-
graph 2.3 step b.
f. Mix the chemical remover well with a mechanical mixer
or a wooden paddle immediately before use as chemical
removers tend to separate on standing. Do not mix by
rolling a drum of chemical remover as this will not mix
the material adequately.
g. Apply a light to medium thick, uniform coat of chemical
remover to the area of the aircraft, equipment, or
component from which the finish system is to be
removed with a long handled, non-metallic brush, speci-
fication MIL-B-23958, (type and style are optional) or a
non-atomizing type sprayer wand fitted to a barrel
pump. Never use an atomized spray to apply chemical
removers. Do not apply thick coats of chemical remov-
ers as this actually slows down the removal rate, creates
a more extensive waste disposal operation, and wastes
expensive chemical removers. Efficient removal re-
quires maintaining a wet film of remover on the surface.
Active ingredients in chemical removers listed in Para-
graph 2.6.2 are highly volatile and evaporate rapidly; so
after about one hour dwell time, they begin to dry out
and no longer react on the finish system as most of the
active ingredients have evaporated. Environmentally
compliant removers listed in Paragraph 2.6.4. have a
maximum dwell time of 24 hours before they become
non-reactive. For an effective removal operation chemi-
cal removers must be applied progressively and in a
planned logical sequence. Apply removers to areas no
larger than can be effectively worked by the personnel
on hand to perform the operation. Removers should not
be applied to a second area prior to completion of the
removal operation in an area being worked. This is
particularly important for extensive removal operations
such as removal of the entire exterior finish system from
an aircraft. Preferably, application of chemical removers
should begin at the highest point of a vertical or sloping
surface to prevent removers from running down onto
surfaces from which the finish system has already been
removed; but this is an optional decision to be made by
local management.
h. Allow a chemical remover listed in Paragraph 2.6.2 to
dwell on the surface undisturbed for 15 minutes, and one
listed in Paragraph 2.6.3 and Paragraph 2.6.4 for 4 hours
and then agitate several spots on the surface with
A-A-58054, Type I, Grade C abrasive mat, or a MIL-
B-23958, Type I or III brush to determine if the finish
system has been loosened down to bare metal. If the
finish system has loosened down to bare metal at this
point, proceed to next step; if not, repeat the 15 minute
or 4 hour dwell and spot agitation procedure until
loosening of the finish system down to bare metal is
indicated or a maximum of one hour or 24 hour dwell
time has elapsed and then proceed to the next step.
i. When the finish system has loosened to bare metal or
exceeds a reasonable dwell time, thoroughly agitate the
entire area on which the chemical remover has been
applied with a MIL-B-23958, Type I or III brush while
exerting as much pressure with the brush as possible.
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