What Effect Does Waterjet What Effect Does Waterjet Cleaning Have on the Surface?Cleaning Have on the Surface?

Thirty Years PerspectiveThirty Years Perspective

Lydia FrenzelLydia FrenzelAdvisory CouncilAdvisory CouncilSan Marcos TXSan Marcos TX

www.advisorycouncil.orgwww.advisorycouncil.org

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Change introduced by High Pressure Change introduced by High Pressure Waterjet Cleaning of coatingsWaterjet Cleaning of coatings

Refresher on the changes over the past 30 years (Water Blasting to Water Jetting)

What I guessed and predicted in 1976 We had a great tool-how could we use it The development of what we mean by a

“CLEAN SURFACE” today

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ReferencesReferences JPCL Ebook on WaterjettingJPCL Ebook on Waterjetting Blogs by Dr. David A. SummersBlogs by Dr. David A. Summers

– bittooth.blogspot.com (10 years of WJ blog)bittooth.blogspot.com (10 years of WJ blog)– waterjetparts.com/h2o/blog/ waterjetparts.com/h2o/blog/

David Summers, “Waterjetting Technology”David Summers, “Waterjetting Technology” Andreas Momber, “Hydroblasting and Andreas Momber, “Hydroblasting and

Coatings of Steel Structures”Coatings of Steel Structures” Paintsquare.comPaintsquare.com Advisorycouncil.org or flashrust.orgAdvisorycouncil.org or flashrust.org

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JPCL WebinarsJPCL Webinars

• Joao Azevedo, Paint Manufacturer, 2014-11-25 Joao Azevedo, Paint Manufacturer, 2014-11-25 Considerations for UHP WJConsiderations for UHP WJ

• Peter Ault, Specifier, Inspector, 2014-09-02 Peter Ault, Specifier, Inspector, 2014-09-02 PerformancePerformance

• Richard Dupuy, Contractor, 2013-05-20, Richard Dupuy, Contractor, 2013-05-20, Operations, EquipmentOperations, Equipment

• Richard Burgess, Inspector, 2012-07-09 Richard Burgess, Inspector, 2012-07-09 WaterJet StandardsWaterJet Standards

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What kind of surface do we need to What kind of surface do we need to make the paint stick?make the paint stick?

What we mean by “clean” has changed over the What we mean by “clean” has changed over the past 30 years.past 30 years.

We used to think that “clean” was to make a We used to think that “clean” was to make a visual appearance with a profile.visual appearance with a profile.

Now we understand that we can “clean” a Now we understand that we can “clean” a surface without changing the profile.surface without changing the profile.

Clean means “Creating the situationClean means “Creating the situationso a coating will perform as expected.”so a coating will perform as expected.”

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Dynamics- Abrasives Compared Dynamics- Abrasives Compared to Waterto Water

Solids hits from the TOP.Solids hits from the TOP.abrades-erodes-erases-moves metal around-gets abrades-erodes-erases-moves metal around-gets embedded- makes hacklesembedded- makes hackles

Changes the profile- Always?Changes the profile- Always? Water drills into crevices and shears to the sides.Water drills into crevices and shears to the sides. Waterjetting can change the character of the surface Waterjetting can change the character of the surface

while the profile remains the same.while the profile remains the same.

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John Keane, Surface Profile for Anti-Corrosion PaintsSSPC 74-01, 1976

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1970’s-1980’s1970’s-1980’sAbrasive blastAbrasive blast

NormalNormalappearance forappearance for

clean steelclean steel

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Top view- abrasive blastTop view- abrasive blast

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Cross view- abrasive blast

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Rust-Back

Abrasive blast cleaning, multiple passes

11Courtesy, Bill Hitzrot, Chesapeake Specialties, 1975

Change of profile with overblasting

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White Metal -Abrasive BlastWhite Metal -Abrasive BlastRust Back- White one day-Rust Back- White one day-

Black areas- formed overnightBlack areas- formed overnight

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Typical abrasive plowing of Typical abrasive plowing of surfacesurface

Courtesy of High Pressure Waterjet Lab, Missouri Institute Courtesy of High Pressure Waterjet Lab, Missouri Institute of Science and Technology, Rolla. Dr. David Summersof Science and Technology, Rolla. Dr. David Summers

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What did we see in 1976-1980 What did we see in 1976-1980 for high pressure waterjetting?for high pressure waterjetting?

Waterjet cleaned surface looked DIFFERENT Waterjet cleaned surface looked DIFFERENT from an abrasive cleaned surface.from an abrasive cleaned surface.

10,000 psi (50-70 MPa) did not deliver 10,000 psi (50-70 MPa) did not deliver enough energy to surface to disrupt old rust enough energy to surface to disrupt old rust bond to surface. bond to surface.

Appearance opposite to abrasive blast.Appearance opposite to abrasive blast. Water wetted the entire surface.Water wetted the entire surface. Surface turned blue to golden instantly.Surface turned blue to golden instantly.

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20,000 psi20,000 psi140 MPa140 MPa(1983)(1983)

Dull gray.Dull gray.Continue to Continue to see “paint” see “paint”

stainstain

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140 MPa (20,000 psi)- Top view140 MPa (20,000 psi)- Top viewpattern under corrosionpattern under corrosion

Sharp andSharp and “ “clean”clean”

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Orginally rounded profile?

140 MPa (20,000 psi) Top View140 MPa (20,000 psi) Top Viewpattern under corrosion.pattern under corrosion.

The “profile” produced at the The “profile” produced at the beginning affects the future.beginning affects the future.

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OriginallyAngular gritprofile

140 Mpa (20,000 psi) Side View140 Mpa (20,000 psi) Side ViewWaterjet CleaningWaterjet Cleaning

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Flue gas scrubber which has Flue gas scrubber which has failedfailed

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Abrasive Cleaning –very slowAbrasive Cleaning –very slowLooks good underneathLooks good underneath

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Waterjet (Fan Jet) is about 20 times faster. Waterjet (Fan Jet) is about 20 times faster. Reveals that the entire surface is corroded.Reveals that the entire surface is corroded.

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Cross section of flue gas Cross section of flue gas substrate after cleaning.substrate after cleaning.

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Three basic “terms” of rust found in Three basic “terms” of rust found in standardsstandards

Flash Rust Flash Rust is an oxidation of the steel that occurs is an oxidation of the steel that occurs as wetted carbon as wetted carbon steel driessteel dries OR rusting that occurs when a thin coat of waterborne paint is OR rusting that occurs when a thin coat of waterborne paint is applied over blast cleaned steel. Often looks like rust bloom.applied over blast cleaned steel. Often looks like rust bloom.

Rust-Back (rerusting) Rust-Back (rerusting) is rusting that occurs when freshly exposed, is rusting that occurs when freshly exposed, dry,dry, bare steel is exposed to conditions of high humidity, moisture, or a bare steel is exposed to conditions of high humidity, moisture, or a corrosive atmosphere. It is the term used when steel cleaned by dry abrasive corrosive atmosphere. It is the term used when steel cleaned by dry abrasive blasting, power tools, or wet abrasive blasting begins to rust blasting, power tools, or wet abrasive blasting begins to rust after the steel after the steel surface has completely dried.surface has completely dried.

Rust Bloom Rust Bloom is somewhat uniform rust spread evenly over a large is somewhat uniform rust spread evenly over a large section of the surface.section of the surface.

Long term corrosion is not flash rusting.Long term corrosion is not flash rusting.

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You must get the energy to the surface to disrupt the bond.

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10,000 psi20,000 psi

1983, approximately 1/3 meter x 1/3 meterManually held fan jet. Appeared to be “instant” conversion to inert golden color. Stays that way for days.

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The yellow- golden color is a “Thin Film” refraction.The yellow- golden color is a “Thin Film” refraction.

27Courtesy of Union of American Hebrew CongregationTemple Israel WRJ, Colonial School for the Visually Impaired

Light flash rustLight flash rust

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USS Boxer, LHD 4 San Diego 2002Courtesy: Y & T Consulting

Typical waterjet responseTypical waterjet response

Now let’s move to re-rusting on steel after Now let’s move to re-rusting on steel after cleaning.cleaning.

Grade BC steel – cleaned January 1997 as Grade BC steel – cleaned January 1997 as part of WJ standards preparation. part of WJ standards preparation.

Put over water in 2000. Put over water in 2000. Photo taken June 2006Photo taken June 2006

Still looks the sameStill looks the same

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Test- Wet Abrasive BlastTest- Wet Abrasive Blast

SB 1999-10-16 SB 1999-10-25

SB 1999-11-01 1999-11-11 1999-12-04

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What happens to corrosion sites?What happens to corrosion sites?

Take panels from same sourceTake panels from same source Blast one with abrasiveBlast one with abrasive Pressure wash one, followed by abrasivePressure wash one, followed by abrasive Blast one with UHP WJBlast one with UHP WJ Dry with compressed airDry with compressed air Put inside over water. Leave alone.Put inside over water. Leave alone. Observe.Observe.

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Abrasive blast- 6 yearsAbrasive blast- 6 years

Blasted 2000 to white metal. Placed over water.Blasted 2000 to white metal. Placed over water.

Typical originalplate- 2000

May 2006

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WJ- cleaned in 2000-WJ- cleaned in 2000-placed over water. placed over water.

June 2006 WJWater dripped on the surfate left gelatinous rust

Close UP

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AB steel –cleaned with UHP WJ- June 2006AB steel –cleaned with UHP WJ- June 2006

Stain Stain stayed stayed on. on. Light Light Flash Flash Rust.Rust.

2006-Nov2006-Nov

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WJ plate re-cleaned June 2006WJ plate re-cleaned June 2006

After cleaning with UHP WJ.2006-Nov

June 2006Cleaned with280 MPaUHP WJ

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Direct impact - side shear forces

VerticalVelocity-pressure

Horizontal-Shear-volume

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Shear Loading

Flexing Action

Streamlines change direction due to spinning nozzle

Impact InducedCohesion Erosion

Horizontal flow over irregular surface & rapid changes in flow directionas nozzle spins & moves induces high shear loads at base of any protrusionand high bending moments.

Water SurfaceWater SurfaceDiagram - Roland Lever, 1995, NACE Infrastructure- Baltimore

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Thick abrasion-resistant nonskid. Thick abrasion-resistant nonskid. Effect of pressure to drill through Effect of pressure to drill through

coatingcoating

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Removal of coating from cabinet Removal of coating from cabinet uses mass-flow-hydraulic shearuses mass-flow-hydraulic shear

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Focused path of multi-orifice Focused path of multi-orifice rotating nozzlerotating nozzle

View of flat surface treatment using rotary View of flat surface treatment using rotary head equipped with two water nozzleshead equipped with two water nozzles

40P. Borowski, 2005 WJTA Conf., Rotation Water Jet Kinematics; photo-G. Kuljian

Wetting characteristics of surface Wetting characteristics of surface change significantlychange significantly

McGaulley, W, Shepperson, W., & Berry, Fred, “Comparison of Secondary Surface Preparation over Water Jetted Surface and Effect on Coatings Performance”, SSPC 2001 Conference

Degreased

WJ

Degreased

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Waterjet peening Waterjet peening

WJ cleaningcan influencethe energy of the substratesurface andenhancefatiguestrength.

42Kunaporn, WJTA Proceedings 2001, 2003

““Erosion of steel substrates when exposed to Erosion of steel substrates when exposed to Ultra-Pressure waterjet cleaning systems”Ultra-Pressure waterjet cleaning systems”

Material (steel) Material (steel) is eroded during is eroded during the first two the first two passes. passes. Subsequent Subsequent passes do not passes do not remove more remove more material.material.

DON’T let the DON’T let the nozzle stop!nozzle stop!

43Miller & Swenson, WJTA Proceedings, 1999

1.009

2.017

3.018

6.018

.700

Influence of depainting method on substrate Influence of depainting method on substrate surface profile- WJTA, 2011surface profile- WJTA, 2011

Original topography before coating

After paint stripping with grit- overblast

After paint stripping with WJ. Return to original profile 44

Profile. Bronze William Penn Statue Profile. Bronze William Penn Statue (Boot)- Philadelphia City Hall(Boot)- Philadelphia City Hall

Before Cleaning

After Cleaning

45Photo courtesy of Rod Draughon- 1989 NACE Corrosion 119

Microscopic ViewMicroscopic ViewBronze statute -white corrosionBronze statute -white corrosion

UHP WJ can be used on “soft” metals.UHP WJ can be used on “soft” metals.

Photo courtesy of Rod Draughon- 1989 NACE Corrosion 119

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Lawrence Crum, Univ of Wash, ACS Lawrence Crum, Univ of Wash, ACS “Chemistry,” Summer, 2000, p. 20,“Chemistry,” Summer, 2000, p. 20,

SonochemistrySonochemistry

Cavitation near a solid surface can induce a microjet of liquid that stream through the bubble upon implosion.

A 100 micron droplet can get into a 10 micron crack.1. 47

SonoChemistrySonoChemistry www.scs.uiuc.edu/suslick, “The Chemistry of www.scs.uiuc.edu/suslick, “The Chemistry of

UltraSound,” by Kenneth S. SuslickUltraSound,” by Kenneth S. Suslick The time of impact is short – so power level The time of impact is short – so power level

is high.is high.

This is taking placeIn some of the areas of The nozzle stream.The result- That “instant” gold Color- Increases chemical Reactivity.

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VanKuiken Patent VanKuiken Patent 5,380,564 (1995)5,380,564 (1995)

AluminumAluminum Grit BlastGrit Blast Thermal Spray CoatingThermal Spray Coating

Adhesion 3000 psiAdhesion 3000 psi

WaterjetWaterjet 10-75 micron profile10-75 micron profile Thermal Spray CoatingThermal Spray Coating

Adhesion 6000 PSIAdhesion 6000 PSI

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VanKuiken Patent 5,626,674 (1995) VanKuiken Patent 5,626,674 (1995)

Aluminum50,000 psi (350 MPa) 1 gallon (3.8 liters) per minute

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Surface roughening of metallic substrate Surface roughening of metallic substrate by high pressure pure waterjetby high pressure pure waterjet

350 MPa (50,000 psi) (Steel alloy Threshold 350 MPa (50,000 psi) (Steel alloy Threshold pressure)pressure)

““Excellent bonding of a thermal spray overlay was Excellent bonding of a thermal spray overlay was obtained with this surface preparation having an obtained with this surface preparation having an absolutely clean interface.”absolutely clean interface.”

……the detail of the eroded surface increases with the detail of the eroded surface increases with increasing magnification, suggest the waterjet erosion increasing magnification, suggest the waterjet erosion produces a produces a fractalfractal surface. … granular features of surface. … granular features of about 2 microns … rather micro-faceted.about 2 microns … rather micro-faceted.

51Surface and Coatings Technology, Vol 76-77, p. 95-100, 1995

Profiles in SteelProfiles in Steel Abrasive createdAbrasive created WaterJet WaterJet

createdcreated

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What makes a good surface for coatings?What makes a good surface for coatings?

Molecular bonding- mechanical bondingMolecular bonding- mechanical bonding Expansion of surface area increase the Expansion of surface area increase the

number of potentially reactive sites…for number of potentially reactive sites…for primary or secondary bonding.primary or secondary bonding.

The thin, impermeable oxide layer that The thin, impermeable oxide layer that immediately reforms on newly bared iron immediately reforms on newly bared iron surface is .. adherent and suitable as a surface is .. adherent and suitable as a substrate for good adhesion.substrate for good adhesion.

53C. Hare- JPCL 1996 -1999 series

– – Reassurance –Reassurance –In order to erode steel in a system In order to erode steel in a system

that is set up for cleaning, you would that is set up for cleaning, you would need approximately need approximately 150150 times more times more

energy density than is normally energy density than is normally found in the 280 MPa (40,000 psi) found in the 280 MPa (40,000 psi)

system.system.

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What kind of surface do we need to make What kind of surface do we need to make the paint stick?the paint stick?– Maximum surface areaMaximum surface area– Maximum Wetting PropertiesMaximum Wetting Properties– Lack of Embedded MaterialLack of Embedded Material– Removal of non-visible- oil, grease, dirt, saltRemoval of non-visible- oil, grease, dirt, salt

Are we looking for longevity or short termAre we looking for longevity or short term– Asset managementAsset management

Clean means “Creating the situationClean means “Creating the situationso a coating will perform as expected”so a coating will perform as expected”

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Abrasive Cleaning and Pressurized Abrasive Cleaning and Pressurized Water Cleaning are Two Water Cleaning are Two DifferentDifferent Tools Tools

Dry or Wet Abrasive Dry or Wet Abrasive WaterJetWaterJet New and RepairNew and Repair RepairRepair Makes new profileMakes new profile Exposes profile Exposes profile

under paint or corrosionunder paint or corrosion Erases from the TopErases from the Top Shears at interfaceShears at interface Looks UniformLooks Uniform Exposes all problemsExposes all problems Cleans top, leaveCleans top, leave Gets into crevices, Gets into crevices, material in crevices material in crevices Could leave top Could leave top (stain)(stain)

material material NO Rust Back Allowed (Dry)NO Rust Back Allowed (Dry)Flash Rust allowedFlash Rust allowed Flash Rust Allowed (Wet)Flash Rust Allowed (Wet)

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What kind of surface do we need to What kind of surface do we need to make the paint stick? make the paint stick?

A high ratio of surface area to unit A high ratio of surface area to unit

planar areaplanar areaReactive sites over the entire surfaceReactive sites over the entire surface

Excellent Wetting PropertiesExcellent Wetting PropertiesLack of embedded materialLack of embedded material

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SummarySummary Over the past 30 years, we have changed our concept of what Over the past 30 years, we have changed our concept of what

type of surface we must achieve in order to be “clean.”type of surface we must achieve in order to be “clean.” Surface Preparation- Creating the situation so the coating will Surface Preparation- Creating the situation so the coating will

perform as expected.perform as expected. We used to talk about the “process” (abrasive blasting) for a We used to talk about the “process” (abrasive blasting) for a

clean surface.clean surface. Now we talk about the end result-performance for a “clean” Now we talk about the end result-performance for a “clean”

surface. surface. Around 1994- the industry had the “AHA” momentAround 1994- the industry had the “AHA” moment

– – It’s waterjetting, not abrasive blasting.It’s waterjetting, not abrasive blasting. WJ has fundamentally changed our language and concept of WJ has fundamentally changed our language and concept of

what is occurring at the surface and what we are trying to what is occurring at the surface and what we are trying to achieve.achieve.

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Where to use Waterjetting?

See JPCL, Dec., 2002, p. 57-65

AutomationAutomation

Major chemical manufacturers are Major chemical manufacturers are advocating that hand-held waterjetting advocating that hand-held waterjetting cleaning is minimized. cleaning is minimized.

Equipment will be shown WJTA- IMCA Bi-Equipment will be shown WJTA- IMCA Bi-Annual Conference- November 2-4, 2015 Annual Conference- November 2-4, 2015 New OrleansNew Orleans

www.wjtaimca2015.comwww.wjtaimca2015.com YouTube videos and “Basics” slides from YouTube videos and “Basics” slides from

WJTA 2013 are online.WJTA 2013 are online.60

Industry Best Practices for Industry Best Practices for Hydroblast Hose Assembly Hydroblast Hose Assembly

ApplicationsApplications NAHAD Hose Safety Institute Whitepaper NAHAD Hose Safety Institute Whitepaper

(2014):(2014): Safety First…the New Normal in High Pressure Safety First…the New Normal in High Pressure

HydroblastingHydroblasting Color Coding of HosesColor Coding of Hoses http://www.wjta.org/images/wjta/http://www.wjta.org/images/wjta/

hydroblast_whitepaper.pdf hydroblast_whitepaper.pdf 

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Slide of inside corner – outside Slide of inside corner – outside corner cleaning heads wt vaccuumcorner cleaning heads wt vaccuum

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Under development- reported in March, 2015- Under development- reported in March, 2015- Fast, smooth coatings removal Fast, smooth coatings removal

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Hand tools with surface- Hand tools with surface- detection sensorsdetection sensors

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No trigger pressure, no tumble box, No trigger pressure, no tumble box, electronic on-off; electronic on-off;

ergonomic design-used in Europeergonomic design-used in Europe

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Early Days

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Cut resistant Cut resistant clothing is clothing is

becoming more becoming more operator friendlyoperator friendly

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Modular Units and CoverallsModular Units and Coveralls

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Eliminate the shredded boot!Eliminate the shredded boot!

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Any questions??Any questions??www.paintsquare.comwww.paintsquare.com

Grade DGrade D

Optimized removal ParametersOptimized removal Parameters

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