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HANDY
HINTS :
Painting and Preparation |
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SURFACE
PREPARATION AND PAINTING SPECIFICATIONS |
| Iron
and Steel |
Iron and Steel requires the most thorough surface preparation
and the protection of an adequate paint system. The
most effective methods for cleaning iron and steel are shot
blasting, grit blasting, flame cleaning, impact needle guns
and specific forms of chemical cleaning. These methods remove
scale, rust and other contamination from various types of
iron and steel. Residues from these processes require removal,
and therefore the total preparatory cost can be high.
Hand
cleaning methods of scale chipping, scraping and wide brushing
must be as thorough as possible.
There
should be no delay for priming clean iron or steel, as exposure
to air will cause the surface to deteriorate after a very
short interval. Priming within one hour of preparation is
advised. Priming and subsequent painting of iron and steel
should be done under cover in well-ventilated, warm, dry areas
to enable maximum surface protection.
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| PREPARATION
AND PRIMING |
1.
New or Unpainted
Remove oil or grease by solvent cleaning and wiping off with
clean cloth.
Remove all scale, rust and other contamination to produce
the required standard surface preparation. Ensure that the
surface is completely dry and dust free. Apply
an even coat of primer immediately, brushing well and ensuring
that all edges are adequately coated. |
2.
Pre-Primed Iron and Steel
Make sure the primer is sound and has been applied to an adequately
prepared surface. Ensure
that the surface is dry, and small surface defects rectified
and any bare metal cleaned free from rust etc.,
Where
the primer is not satisfactory or the metal not adequately
prepared, remove paint, scale, rust etc., and treat the
surface as for unpainted iron and steel.
Ensure
that all surfaces are dry and free from loose particles;
and prime or spot prime according to surface requirements. |
3.
Previously Painted Iron and Steel
Where the surface is in poor condition, remove all the old
paint, and prepare as for unpainted iron and steel.
Iron
and steel in generally unsound condition should be checked
for detective paint, which should be removed. Prime all
bare metal surfaces immediately and allow drying. Degrease,
remaining painted surfaces with white spirit & wash
with a solution with Teepol detergent. Rinse thoroughly
with clean water.
Prime
or spot prime bare metal immediately according to surface
requirements. |
4.
Bitumen - Coated Iron and Steel
Because of the risk -of cracking or excessive bleeding, new
bitumen, or thick soft coatings of bituminous materials are
not suitable for painting. The
hard bituminous material is usually possible to paint when
they are effectively sealed with a material to prevent bleeding.
Ensure
that the surface is prepared free from dirt grease and loose
particles. Remove all defective coatings and all corrosion
from bare metal.
Apply
one or two coats of Robbialac Aluminum Primer as required
to stop bleeding. |
5.
Galvanised Iron and Steel
New Galvanised surfaces are usually too smooth to allow firm
adhesion of paint. However, on exposure for some weeks to
weathering, the surface gets sufficiently etched to provide
better adhesion for paint. As it is often necessary to apply
the primer directly to un-weathered galvanised surfaces, special
care should be taken to remove all grease, oil or other contaminants,
to enable the primer to have direct contact with the clean
metal surface. Remove
oil and grease in small areas by degreasing with ample White
Spirit and remove residue. Failure to remove residue results
in a very thin film of oil or grease over a much larger
area than the original contamination.
Large
areas such are best cleaned free of oil and grease with
White Spirit, and then washed with a solution of Teepol
detergent. Adequate rinsing to remove all washing residue
is essential, and warm water will assist surface drying. |
6.
New galvanised Iron and Steel
Remove all oil and grease and surface contamination completely.
Ensure
that all surfaces are dry and prime immediately with a thin
coat of Robbialac Zinc Chromate or Robbialac Zinc Primer
(Grey). |
7.
Weathercoat Galvanised Iron and Steel
Clean surfaces thoroughly. Remove all rust by scraping and
wire brushing. Ensure surface is dry and dust free.
Prime
immediately with Robbialac Metal primer, brushing well into
the surface. |
8.
Previously Painted Galvanised Iron and Steel
Where there is flaking or lifting, complete removal of paint
is advised. When
paintwork is generally sound, remove oil or grease with
White Spirit and wash whole surface with Teepol detergent
and rinse thoroughly.
Check
for rust, and if present, remove completely. Rub down all
painted areas, dust off and ensure that all surfaces are
dry.
Prime
or spot prime immediately with Robbialac Metal Primer accordingly. |
9.
Aluminum and Aluminum alloys
Aluminum has a rather greasy, smooth surface, which when exposed,
forms ‘white corrosion’. Therefore any grease and
corrosion should be removed to provide a key surface for the
primer. Aluminum
should be kept from contact with caustic solutions and should
not be primed with lead pigmented primers.
Prepare
the bare metal with abrasive paper/white spirit combination.
Wipe off with clean clothes soaked in White Spirit and remove
all residue with dry, clean clothes.
Prime
with Robbialac Zinc Chromate Primer immediately. |
10.
Copper, Brass and similar alloys
These metals are difficult to paint, and are better left unpainted.
Where painting is essential, the surface requires preparation
as for Aluminum surfaces. Normal
Primers are not recommended. Instead an application of Robbialac
Super Gloss direct to the clean surface is advised. |
11.
Previously Painted Non-Ferrous Metals
Where flaking and lifting is extensive, or other signs of
weak adhesion is present, remove all old paint completely
and treat as for a new surface. Where
the surface coating is sound, remove grease or oil contamination
with White Spirit, wash with a solution of Teepol detergent
and water, and rinse thoroughly with clean water.
Spot
prime any bare metal with Robbialac Metal Primer. |
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