When cleaning plastic parts, you should be careful
cleaning. This cleaning includes using a heavy-
duty alkaline cleaner and blasting.
to avoid heat buildup. After cleaning thoroughly,
Soft carbon deposits are removed by de-
dry the part and apply corrosion prevention
compounds.
creasing and steam cleaning. Decreasing removes
dirt and sludge by immersing or spraying the part
with cleaning solvent. Hard carbon deposits are
Vapor Decreasing
removed by decarbonizing, brushing, scraping, or
Vapor decreasing removes oil, grease, and
grit-blasting. The following text provides general
preservative compound by solvent vapor. A flat
cleaning procedures to familiarize you with the
bottom tank with heating coils on the bottom and
methods and materials used for cleaning parts.
Always refer to the appropriate maintenance
cooling coils midway around the tank is required.
The part is suspended in the vapor area below the
manual for the latest cleaning procedures.
cooling coils. Heated cleaning solvent vapor
Constant changes are made in cleaning and
condenses on the cool part. It dissolves oils,
finishing (coatings) materials.
grease, and preservatives. Cleaning action stops
Degreasing (Solvent Cleaning)
when the part reaches the vapor temperature. If
further decreasing is necessary, the part must be
cooled before using vapor degreaser again. Vapor
Small accumulations of grease, oil, and dirt
decreasing cannot be used on titanium parts
may be removed by hydrocarbon solvent cleaning.
This method is not effective in removing baked-
because recommended solvents cause stress-
on oil deposits or most surface coatings.
corrosion at high temperatures.
Recommended solvents for vapor decreasing
are trichloroethane (O-T-620), trichlorotrifluro-
WARNING
ethane (MIL-L-81302), and perchloroethylene.
These solvents are designed to clean metals by the
Decreasing solvents are flammable, and
vapor cleaning method because their high vapor
their vapors are toxic. Keep all solvents
density results in small vapor loss.
away from open flames, and use only in
Decarbonizing
well-ventilated areas. Avoid solvent con-
tact with skin, eyes, and clothing by wear-
Decarbonizing is the chemical removal of
ing rubber gloves, a face shield or goggles,
carbon deposits. Decarbonizing agents are
and an apron or coveralls.
detergents, sodium silicates, chlorinated hydro-
carbons, and various acid solutions. This cleaning
Dry-cleaning solvent (P-D-680) is the recom-
method is effective for paint stripping, rust
mended cleaner. Solvent cleaning uses a tank with
removal, and general cleaning of ferrous and high-
cleaning solvent to soak the part clean. Some
tanks have pumps to provide mechanical agita-
temperature parts. Parts are soaked in hot or cold
tanks and rinsed with high-pressure water.
tion to help clean parts. You can also use a soft-
bristle brush to remove stubborn stains. The
cleaning tank should have a hinged, counter-
weighted cover so it can be covered when not in
WARNING
use. Since some plastic- and rubber-based
Carbon removers require careful handling.
materials are attacked by hydrocarbon solvents,
Wear goggles, rubber gloves, and aprons
steam clean these parts to remove contaminants.
when using these solutions.
Steam Cleaning
Some carbon removers attack aluminum and
magnesium parts if they are left in the solution
Steam cleaning is a cleaning process used when
too long. There is also the possibility of a chemical
you do not want to remove paint and surface
reaction when aluminum, magnesium, and steel
coatings. To properly clean with steam, it is
parts are immersed in the same tank. This practice
necessary to add cleaning compounds. Do not
steam clean oil-impregnated parts.
often results in damage to magnesium parts, such
as dissimilar metal corrosion.
Set steam valve to the proper strength and
Upon removal from cleaning solutions, rinse
force required for the job. Hold the steam gun
the parts in a soap-and-water solution or with a
about 12 inches from the part at a 45-degree angle.
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