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Pre-Cleaning:
 All surfaces must be
cleaned to remove
OIL,
grease, old paint, dirt
and other
contamination.
Large quantities of oil,
grease, eureka,
Royal Rust Coat will be
physically removed by
scrapping using
scrappers,putty knives
or
Chisels.
All remaining OIL,
grease, loose paint or
other contamination must
be removed by
application of a
biodegradable water
based
surfactant type
cleaner approved by the
manufacturer of the
coating being applied
followed by low pressure
fresh water
cleaner.
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Surface Preparation:
Surface should be
prepared in accordance
with the recommendations
of the paint
coating
specifications and
product data sheets.
When tested surfaces are
shown to contain more
than 10 Ug/cm2 of
Chlorides, this
surface
shall be high pressure
water cleaned (HPWC)
with clean fresh water
and
any recommended
additives as per the
data sheet.
Checking the salt and
Chloride content on the
surface using salt
detection kit #
134 Elcometer, Chlorides
content on the cleaned
surfaces should not
exceed 7
Ug/cm2.
Cleaned surfaces may
have to be washed with
the freshwater /
de-chloride wash
solution more than once
until this limit of
Chlorides is reached.
Since most of our
surfaces are subjected
to aggressive and severe
conditions, the
blasting
standard required and
which will be achieved
is Sa - 2.5 (NACE
2/sspc - sp
10 - 63), or
(ISO 8501 - 1 Sa - 2
1/2) "near white"
blasting cleaning using
Garnet
as an abrasive
with 20/40 to 30/60 mesh
size - No recycle ,
"Clemco" American
made
blasters, 200 lit
capacity, with remote
control and breathing
apparatus are
going to
be used.
Surface profile 2 - 4
mills RMS is to be
obtained - Elcometer 123
surface profile
gauge to be used.
Weld seams, metal
silvers, sharp edges,
weld spatters will be
removed, using power
tools to provide a
uniform, non-polished
surface.
Sharp edges to be
rounded by
grinding to
approx. 2mm radius, as
paint coatings tend to
run away from sharp
edges, resulting in thin
coating and reduced
protection.
The usage of power wire
impact tools, power wire
brushes, power wire
sanders should
physically kept very
limited because it may
lead to the smoothening
and polishing of the
metal surface
and
finally destroying the
surface profile - peaks
and valleys - that will
reduce the
key for the
subsequent paint
coating.
Blasted surfaces shall
be coated with one coat
of primer during the
same day that
blasting
was done and before any
visible deterioration
occurs.
If
before painting the
surfaces become
contaminated in anyway
or oxidation has
occurred, surface
preparation is to be
repeated.
All abrasive and dust
from blasting operation
shall be removed from
surfaces before
painting
application, by brushing
and sweeping.
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