Surface Preparation For Marine Painta and Coatings Brochure

poxy Oilserv Limited as major distributors of Marine coatings and paints, have a large stock of different brands of marine paints. Our Marine Protective Coatings are high quality paints, and are of the few quality brand for coatings approved worldwide and in Nigeria for the protection and maintenance of marine equipment or vessel.

Our marine paints and coatings are used because they offer outstanding chemical and water resistance, are extremely durable and have excellent adhesion to a variety of substrates.

They provide protection for marine machinery, steel, wood, ship bottoms, tanks, pipelines concrete ship decks in harsh environment against corrosion.

Coating is the most cost-effective way of providing protection for corrosion and to prolong the lifespan of marine vessel and other offshore structures. Paint and preservative coatings can be found on both interior and exterior surfaces of a ship with separate areas being coated differently according to their particular kind of exposure. Before paint can be effective as an anticorrosive, the substrate to which it is to be applied must be thoroughly cleaned to obtain maximum adhesion of paint to steel.

The surface preparation is the most vital aspect of any paint process. The success of any coating system depends on careful and complete preparation of the structure before painting and it is an important factor in achieving high bond strength, lifespan of bonded joints paint, durability and to prevent paint failure.

The surface of the system should be properly prepared before coating the substrate. All cracks, holes and other imperfections which may not allow the paint to adhere or bond well with the substrate should be properly treated. Smooth and an even surface must be achieved on the substrate before any paint or coating products should be applied.

Factors To Consider Before Implementing Surface Preparation of Vessel

The first thing to consider is to identify the composition or the type of substrate you want to coat because different substrate materials will require different types of adhesives for bonding and different methods of surface preparation; this is important to ensure the chosen pretreatment procedure will effectively prepare the surface without damaging it. Some surfaces may require nothing more than having the dust brushed away or to wash it with light detergent while others may require elaborate surface preparation procedures prior to bonding. Whatever materials you work with, it’s a good idea to equip yourself with a comprehensive knowledge of surface preparation. 

The second factor is to identify the type of contaminant on the surface of substrate which could be grease, soil, oil, dirty, living organize like algae or other unwanted bodies. This will help to determine the most effective and safest method for removing the debris or contaminants. 

The type of substrate – Maintenance or new coating because this will also determine the type of surface preparation method to use. 

Ensure Temperature & Humidity Control: The tem per atur e and humidity where the substrate is located should be put into account; it is must be in a highly controlled environment Proper surface preparation enhances adhesion of the film to the surface. When coating a surface prepared by blasting, the real issue is not time: the key criterion is that the steel temperature shall always be at least 3 °C (5 °F) higher than the calculated dew point. This safety margin is sufficient for all types of coatings. Consideration of factors such as time, temperature, and humidity must be the responsibility of the inspector in the course of surface preparation and coating of the substrate. No final blast cleaning or coating application shall be done if the relative humidity is more than 85 % and when the steel temperature is less than 3 °C above the dew point. No coating shall be applied or cured at temperatures below 0 °C of the coating selected and the expected service life of the coating system.

The following factors are caused by moisture: It has been estimated that 60 to 80% of all premature coating failures are caused either completely or partially by inadequate or improper surface preparation. 

Common surface preparation defects include flash rust, which occurs if the surface is subjected to environmental factors before the first coat is applied, and prevents the coating from adhering properly to the substrate surface after blasting.

The presence of high humidity conditions often causes the formation of rust bloom on the metal surface, resulting in blistering and delamination.  High atmospheric humidity enhances condensation of moisture on the surface.  Condensation can result in flash rust that causes the coating to fail.  Surface condensation, if painted over, may result in blistering and delamination.

International Standard for Surface Preparation SSPC/ ISO 8501-1/ NACE/ Method of surface preparation Various surface preparation methods are adopted based on the requirements of the paint system used and the surface of the substrate. Various methods of surface preparation are available.

The Society for Protective Coatings (SSPC), NACE International (NACE), American Water Works Association (AWWA) and the American Society for Testing and Materials (ASTM) all make reference to various standards that define degrees and methods of surface preparation. The most widely used surface preparation specifications are those published in Steel Structures Painting Manual, Vol. 2, Systems and Specifications. Given below is a brief description of the various SSPC and NACE surface preparation standards. It is recommended that you refer to the SSPC or NACE standards for the complete text of the specifications. The specifications contain detailed methods and practices for preparing surfaces and the standard stated below must be adhere to when preparing any surface for coating.

ISO 8501 ranks cleanliness levels in order of increasing work required.

Sa 1 Light Blast Cleaning Sa 2 Thorough Blast Cleaning Sa 3 Blast Cleaning to Visually Clean Steel Solvent Cleaning SSPC-SP-01/ ISO-Removal of all visible oil, grease, dirt, soil, salts as well as, similar organic compounds from steel surfaces by cleaning with solvent, vapor, cleaning compound, alkali, emulsion, or steam. Solvents can be directly applied onto the surface, used on scrubbing brushes or rags, or surfaces being immersed in the solvent.The best way to avoid spreading the contaminants is to use contaminant free solvents. Change rags or scrubbing brushes and cleaning solution frequently so that deposits of oil and grease are not spread over additional areas in the cleaning process. Be sure to allow adequate ventilation. Solvent cleaning can be done using organic, inorganic, petroleum based, alkaline cleaners, acidic cleaners, and detergents but the solvent should be selected based on the substrate and contaminants.

Hand Tool/ SSPC-SP-02/ St 2 Cleaning Removal all loose rust, loose mill scale, and loose paint to a degree specified, by hand chipping, scraping, sanding and wire brushing.

Power Tool Cleaning / SSPC-SP-03 /St 3 Removal of all loose rust, loose mill scale, and loose paint to degree specified, by power tool chipping, power tool descaling, power sanding, power wire brushing and power grinding.

White Metal Blast Cleaning/ SSPC-SP-05/ Sa 3/ #1 Removal of all visible rust, mill scale, paint, and foreign matter by blast cleaning by wheel or nozzle (dry or wet) using sand, grit or shot. (For very corrosive atmospheres where high cost of cleaning is warranted)

in floating

Commercial Blast Cleaning/ SSPC-SP-06/ Sa 2/ #3 Blast cleaning until at least two-thirds of the surface area is free of all visible residues. (For conditions where thoroughly cleaned surface is required) Brush-off Blast Cleaning / SSPC-SP-07/ Sa 1/#4 Blast cleaning of all except tightly adhering residues of mill scale, rust and coatings, exposing numerous evenly distributed flecks of underlying metal.

Pickling/ SSPC-SP-08 /ISO-Complete removal of rust and mill scale by acid pickling, diplex pickling, or electrolytic pickling.

Weathering & Blast Cleaning/ SSPC-SP-09 Near White Blast Cleaning - SSPC-SP-10 /Sa 2½/#2 Blast cleaning nearly to white metal cleanliness, until at least 95% of the surface area is free of all visible residues. (for high humidity, chemical atmosphere, marine, or other corrosive environments)

Power Tool/ SSPC-SP-11/ISO -Cleaning to Bare Metal Complete removal of all rust, scale and paint by power tools, with resultant surface profile.

Surface Preparation and Cleaning of Steel and Other Hard Materials

by High and Ultrahigh Pressure Water Jetting prior to recoating.

Industrial Blast/ SSPC-CP-14/ISO--/#8 Cleaning Surfaces viewed without magnification, are free of all visible oil, grease, dust, and dirt. Traces of tightly adherent mill scale, rust and coating residue are permitted to remain on 10% of each unit area of the surface if they are evenly distributed.

Surface Preparation of Concrete/SSPC-CP13/ISO--/#13 This standard gives requirements for surface preparation of concrete by mechanical, chemical, or thermal methods prior to the application of bonded protective coating or lining systems. The requirements of this standard are applicable to all types of cementitious surfaces including cast-in-place concrete floors and walls, pre-cast slabs, masonry walls and shotcrete surfaces.

An acceptable prepared concrete surface should be free of contaminants, laitance, loosely adhering concrete, and dust, and should provide a dry, sound, uniform substrate suitable for the application of protective coating or lining systems.

SSPC-SP16- Brush-Off Blast Cleaning of Non-Ferrous Metals application of a protective coating. It is used when adding a surface profile to stainless steel, galvanized steel, copper and other metals that are not carbon steel. It requires a minimum surface profile of .75 mil (19 micrometers) and for the surface to be free of loose coating and other contaminants, as verified by a visual inspection.

Grit and sand blasting of Aluminium parts Grit blast to bright, clean aluminum with a 2–3 mils (50–75 microns) profile. If profile is particularly jagged, grind to remove "spikes," providing a more uniform surface.

Blow off the surface thoroughly with clean, dry compressed air or vacuum to remove all blast/grind/sanding residue and any dust or dirt. Use a brush or broom if necessary.

Wood - Exterior Wood must be clean and dry.

Knots and pitch streaks must be scraped, and sanded.

Patch all nail holes and imperfections with a wood filler or putty and sand smooth. Every contaminant should be cleaned before priming or painting.

Wood - Interior All finishing lumber and flooring must be stored in dry, warm rooms to prevent absorption of moisture, shrinkage, and roughening of the wood. All surfaces must be sanded smooth, with the grain, never across it. Surface blemishes must be corrected and the area cleaned of dust before coating.

Vinyl Siding Vinyl siding must be cleaned thoroughly by scrubbing with a warm, soapy water solution. Rinse thoroughly.

Priming

Priming is the final stage of surface preparation before the coating.

Primer or undercoat is a preparatory coating put on materials before painting. Priming ensures better adhesion of paint to the surface, increases paint durability, and provides additional protection for the material being painted.

It is very important to apply the primer as soon as possible after the surface has been prepared. This is to protect the freshly blasted surface as corrosion starts immediately after the surface is prepared and the primer alleviates this. Apply the primer to a clean, dry surface by brushing or spraying. The primer should be applied as a thin coat. If coloured, the appearance of the metal should be transparent and mottled. Allow the primer to air dry for 30 – 60 minutes. It is important that during this time airborne contaminants do not settle on the surface as this could affect the adhesion of the topcoat.

Window of Time – Surface Preparation to Priming All prepared steel must be primed within 4-hours

To prevent rust-back, all prepared steel must receive a primer coat within 8-hours.

All steel not protected within 8-hours shall be re-blast cleaned.

All prepared steel must be primed within 24-hours of the time abrasive blast cleaning was initiated.

All steel abrasive blast cleaned during the work shift must be primed within that same work shift. Prepared steel not protected within the same work shift shall be re-blast cleaned prior to coating.

Priming on Wood Primers are also applied on the surface of wood after surface preparation to help the paint to undergo its proper, complete curing cycle. Wood are very porous and will absorb the solvent from paint thereby causing the paint to dry prematurely. latex and alkyd-based paints polymerises when curing that is they undergoes chemical reaction after painting which requires paint to dry slowly rather than being absorbed. Primer prevents water proofing effect of paint.

Powerful And Safe Coatings For The Marine Industry

18 Adesina Street Off Obafemi Awolowo Road Ikeja Lagos Email: sales@epoxyoil.com Tel: (234) 8053390168

238 Aba Road (Onyejieke Plaza) Rumuogba Port Harcourt Rivers State Tel: (234) 8053390161 30/32 Ndidem Usang Iso Road Marian, Calabar Cross Rivers Sate Tel: (234) 8053398754