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Surface PreparationWarners Suen
Surface Preparation and Coating DivisionEXA GROUP LTD
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Surface Preparation is important?
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Tools For Cleaning
•Hands Tools-Wire brushes, Scrapers, Chisels, etc.
•Power Tools-Rotary wire brushes, Needle Scaler, Grinder, MBX, etc.
•Dry Grit blasting-Mineral, e.g. SiO2, Al2O3, Fe2O-Soda powder, Corn powder, Dry Ice (CO2), etc.
•Water jetting-LPWC, HPWC, HPWJ, UHPWJ-Slurry blast- Inhibitor
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Visible contaminant- Heavy Rust- Mill Scale- Heavy Deposits (Salts and Mineral
Sludge)- Oil / Grease / Waxes (Petroleum
Based)- Old Coatings
Invisible contaminant- Soluble Salts (Chlorides, Sulphates- Acid / Alkali- Fatty Acids, Petroleum- Silicone
Contaminant Removal
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Standard of Surface CleanlinessAbrasive Blasting
Standard RandomStaining
Cleanliness
NACE No.1 / SSPC-SP 5 / Sa 3White Metal Blast Cleaning
None Free of all visible oil, grease,dust, dirt, mill scale, rust,coating, oxides, corrosionproducts, and other foreignmatter
NACE No.2 / SSPC-SP 10 / Sa 2.5Near-White Metal Blast Cleaning
5%
NACE No.3 / SSPC-SP 6 / Sa 2Commercial Blast Cleaning
33%
NACE No.4 / SSPC-SP 7 / Sa 1Brush off Blast Cleaning
Traces of tightly adherent mill scale, rust,and coating residues are permitted toremain on 10% of each unit area
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Regulations
United Nations – IMO (International Marine Organization)SOLAS (Safety of Life at Sea)SOLAS Regulation 3-2 based on IMO Recommendation A
798 of July 1, 1998 stares that ship’s ballast tanks shall beabrasive blasted to ISO 8501 Sa 2 ½ (Near White Metal).
©2008 Sponge-Jet Inc. All rights reserved.
Background
Weld seams are rarely prepared properly prior to coating.
Even if prepared properly, are normally the first location of corrosion due tosurface irregularities, stress corrosion, increased hardness and the low levelgalvanic reaction of the weld to the adjacent steel.
US NAVY – Guidelines indicate thatthe best coatings applied over powertool preparation will last a maximumof 3 years vs 20-30 years forabrasive blasted surfaces.
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Life Cycle Costs
Shipyards rarely have a vested interest in coating performance greaterthan 5 years – in fact generally their liability ends at 1 year or less.
In a cost model on the economics of coatings in shipsballast tanks 25 year life cycle cost were reported forvarious quality of coatings systems*.
• A common system (with 5 year expected life) wouldultimately cost $113 per square meter.• A high performance system (with a 30 yearexpected life) would ultimately cost $46 per squaremeter.
*Ref: Economics of Coatings/Corrosion Protection of Ships. Johnny Eliasson, Stolt-Nielsen Transportation Group B.V.
©2008 Sponge-Jet Inc. All rights reserved.
Normal Cleaning Practices
The reason prefer hand tools to abrasiveblasting is:
• Does not damage adjacent coating withblast media rebound.
• Can be done in close proximity to othertrades such as pipe fitters andelectricians.
• Minimal dust collection so ventilationducts are not required throughout theship.
©2008 Sponge-Jet Inc. All rights reserved.
Goals of Abrasive Blasting
Clean Rust Create Profile Dust Control Low Pressure
Bead Blasting
Wheel Blasting
Hydro Blasting
Wet AbrasiveBlasting
Dry Ice Blasting
Bristle Blasting
Bead Blasting
Wheel Blasting
Wet AbrasiveBlasting
Bristle Blasting
Wet AbrasiveBlasting
How manycan cleanthoroughly?
How manycan profileuniformly?
How manycan achievelower dust?
How many canachieve highersafety?
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What is the result?
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SPONGE JET OVERVIEW
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Sponge Blasting Equipment
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Technology of Sponge Media™
Sponge Character:-Soft-Low Rebound-Absorb Dust
Mineral Character:-Stiff-Clean adhesion underpressurized
©2008 Sponge-Jet Inc. All rights reserved.
Ordinary Blasting versus Sponge Media Blasting
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Sponge Media™ Advantages:•Clean, dry blasting process•Low dust generation•Low Rebound•Wide range of profiles•Reusable•Non-Sparking
New Abrasive Blasting Technologies
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Applications – Marine
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Application – Oil and Gas
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How do Sponge Jet Save your Money?
Eliminate Rework
No need rinse or re-blast
Less need for extensive scaffolding
Protect sensitive equipment
Reduce Air Management cost
Reduce Waste Disposal cost
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Achievement of Sponge Blasting
Clean Rust Create Profile Dust Control Low Pressure
99.9%Dust free
Up to S.A. 3White metal
0-100 microns 3 Bars orLess
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Blast Where You Want…When You Want
Call or WhatsApp me on 9203 6351
©2008 Sponge-Jet Inc. All rights reserved.
Additional Information – Emission Test
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©2008 Sponge-Jet Inc. All rights reserved.
Additional Information – Hot Surface Ignition Study
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