aluminium in commercial vehicles - European Aluminium Association

EUROPEAN ALUMINIUM ASSOCIATION ALUMINIUM IN COMMERCIAL VEHICLES CHAPTER XII 155
2. The nature
of stains
Stains on commercial vehicles
may have the following origins:
• Road caused: dirt, salts, mud,
water splash, tyre wear
• Fuel caused: diesel exhaust, soot
• Load caused: cement, asphalt,
chalk, residues of agricultural
products etc.
• Environmentally caused: effects
of air pollution, dust
All these elements, in connection
with humidity, can lead to local
corrosion and fading or destruction
of the paint layer.
In this respect, residues of previously
transported goods prior to
a new load might also be seen as
contamination and require intensive
cleaning.
3. The choice
of detergent
The detergent used for cleaning an
aluminium vehicle must be compatible
with aluminium, means it
must not be too aggressive.
In general, a detergent has to:
• Have a strong effect on all
kinds of dirt
• Allow an efficient removal of
aggressive dirt
• Create a bright visual appearance
of the surface
• Build up a protective film on
top of the paint
• Be in compliance with specific
regulations
• Be biologically degradable
• Be harmless to the user
Detergents are a complex mixture
of up to 20 ingredients to
enable diverse functions at the
same time: degreasing, slight
etching, washing, conserving etc.
4. Application
of the detergent
The cleaning of a vehicle should
not take place in direct sunlight.
Each detergent should be tested
on a raw aluminium surface prior
to first use.
The detergent can be used either
in automatic washing lines or can
be applied manually with the use
of high pressure spray guns,
brushes, cloths etc. Its main
cleaning effects are:
• Chemical
Some elements of the detergent
dissolve the dirt or mineral salts
without attacking the surface
• Physical
Stains are removed by decreasing
the surface tension. Therefore detergents
contain wetting elements
• Mechanical
Stains are removed by spraying
with pressurised detergent or by
abrasion when using brushes
• Temperature
Higher temperatures, or even
water steam, increase the cleaning
effect by increasing the speed
of the chemical reaction between
the detergent and the stain.
Spraying should be done from
bottom to top of the vehicle to
prevent streaking. The residence
time should be sufficient to dissolve
the stains. The detergent
should not dry on the vehicle surface
and washing should be followed
by intensive rinsing with
de-ionized water.