Corrosion of Paint
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7.6.1.3 Alkaline Cleaning
Aqueous solutions of alkaline phosphates, borates, and hydroxides are used
to remove oily soils in much the same way as detergents. After cleaning, they
are washed away with clear water.
7.6.1.4 Emulsion Cleaning
Aqueous emulsions of organic solvents such as mineral spirits and kerosene are used to remove heavy oily soils and greases. After dissolving the
oily soils, the emulsions are flushed away with hot water. Any remaining oily residue is removed using clean solvent, detergent, or alkaline
cleaners.
7.6.1.5 Solvent Cleaning
Organic solvents are effective in removing oily soils. Hand wiping, spraying, or immersion methods may be employed. The solvents and wipers will
become contaminated with these soils and therefore must be changed frequently to prevent oily residues from remaining on the surface. Because
of the hazardous nature of these solvents, safe handling practices must be
employed.
7.6.1.6 Vapor Degreasing
Boiling solvent condenses on the cool surface to be cleaned and flushes away
oily soils but does not remove particulates. Although once very popular, the
use of this process is declining. The process employs chlorinated solvents
that are under regulatory scrutiny by governmental agencies.
7.6.1.7 Steam Cleaning
The application of detergents and alkaline cleaners using steam cleaners
is an effective degreasing method. Heavy greases and waxes are dissolved
and flushed away by the impingement of steam and the action of the chemicals. Hot-water spray cleaning using chemicals is almost as effective as
steam cleaning.
7.6.2 Metal Surface Pretreatment
Because abrasive cleaning removes corrosion, it is also considered a pretreatment. The impingement of blasting media and the action of brushes and
abrasive pads roughen the substrate and thereby improve adhesion. The
other cleaning methods that remove oily soils do not generally remove rust
and corrosion from the substrates.
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7.6.1.3 Alkaline Cleaning
Aqueous solutions of alkaline phosphates, borates, and hydroxides are used
to remove oily soils in much the same way as detergents. After cleaning, they
are washed away with clear water.
7.6.1.4 Emulsion Cleaning
Aqueous emulsions of organic solvents such as mineral spirits and kerosene are used to remove heavy oily soils and greases. After dissolving the
oily soils, the emulsions are flushed away with hot water. Any remaining oily residue is removed using clean solvent, detergent, or alkaline
cleaners.
7.6.1.5 Solvent Cleaning
Organic solvents are effective in removing oily soils. Hand wiping, spraying, or immersion methods may be employed. The solvents and wipers will
become contaminated with these soils and therefore must be changed frequently to prevent oily residues from remaining on the surface. Because
of the hazardous nature of these solvents, safe handling practices must be
employed.
7.6.1.6 Vapor Degreasing
Boiling solvent condenses on the cool surface to be cleaned and flushes away
oily soils but does not remove particulates. Although once very popular, the
use of this process is declining. The process employs chlorinated solvents
that are under regulatory scrutiny by governmental agencies.
7.6.1.7 Steam Cleaning
The application of detergents and alkaline cleaners using steam cleaners
is an effective degreasing method. Heavy greases and waxes are dissolved
and flushed away by the impingement of steam and the action of the chemicals. Hot-water spray cleaning using chemicals is almost as effective as
steam cleaning.
7.6.2 Metal Surface Pretreatment
Because abrasive cleaning removes corrosion, it is also considered a pretreatment. The impingement of blasting media and the action of brushes and
abrasive pads roughen the substrate and thereby improve adhesion. The
other cleaning methods that remove oily soils do not generally remove rust
and corrosion from the substrates.