Technical data

4.6 MECHANICAL PAINT GUN WASHER.
When lower vapor pressure solvents are used to
clean paint guns and their paint supply lines/
hoses, the paint guns must be blown out with
clean, compressed air and the lines/hoses must be
flushed with MIL-T-81772, Type I thinner imme-
diately after they are removed from the paint gun
washer and prior to use to eliminate all traces of
these solvents from the guns and lines/hoses.
These solvents are not compatible with the paints
and primers used on Air Force equipment, and
failure to remove them will contaminate the next
paint system applied with the paint gun and
supply lines/hoses and cause fish eyes and other
paint curing problems.
NOTE
It is highly recommended that an initial hazard-
ous waste collection container be located as near
as possible to the paint gun cleaner so that any
contaminated sludge, solvents, and filters may be
immediately placed in the container without hav-
ing to transport the waste to the collection
container.
The most effective method for cleaning paint spray guns,
paint fluid hoses, and paint pots/cups is by using a mechanical
paint gun washer. These washers use either MIL-T-81772,
Type I or II thinner, TT-T-2935 Parachlorobenzotrifluoride
(PCBTF), purging thinner, or other low vapor pressure
solvents, that contain some VOCs but no HAPs. The solvents
are contained in a closed-loop system, consisting of a cover,
reservoir, sump, pneumatic pump, spray nozzles, pneumatic
controls, and either a filtration or a distillation system. The
container has devices installed inside of it for connecting
paint guns for cleaning of internal as well as external
surfaces. Since these washers are closed loop systems, their
use reduces hazardous waste, volatile organic compound
emissions, solvents required to manually clean the paint
equipment, and hazards to the personnel. Use of paint gun
washers is required to comply with NESHAP rules when
applicable.
a. Equipment fitted with a filtration system reutilizes the
solvent until it is so soiled that it must then be replaced,
and it also requires periodic change out of the filters.
These units are recommended for paint shops with a
medium to low production rate and a high personnel
turnover rate such as many field level maintenance
organizations. The filtration type paint gun cleaners are
relatively simple to operate and require only a minimum
amount of personnel training for safe and effective
operation. There should be at least two people in each
paint shop that are proficient in the operation of the
shop’s paint gun cleaner so that personnel turnover will
not result in a situation where there are no trained
operators present in the shop. Operation of this equip-
ment shall be in accordance with the manufacturer’s
instructions.
NOTE
• For proper disposal of contaminated solvent,
contact local civil engineering authorities for
instructions.
• Solvent replacement shall be done in accor-
dance with manufacturer ’s instructions.
• Contaminated filters are considered hazardous
waste and shall be placed in a hazardous waste
collection container immediately after re-
moval from the paint gun cleaner.
b. Equipment fitted with a distiller recycles the solvent and
separates out the waste and does not require solvent
disposal. These units are recommended for paint shops
with a medium to high production rate and a relatively
stable work force such as found in most depot level
maintenance organizations. The distillation type paint
gun cleaners are relatively difficult to operate and
require a higher degree of personnel training than the
filtration type units for their safe and effective operation.
There should be at least two people in each paint shop
that are proficient in the operation of the shop’s paint
gun cleaner so that personnel turnover will not result in
a situation where there are no trained operators present
in the shop. Operation of this equipment shall be in
accordance with the manufacturer’s instructions.
TO 1-1-8
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