PaintSquare.com
      | Connect Follow us on Twitter Like us on Facebook
About | Subscribe | Advertise
  

 

Problem Solving Forum

| More

December 13 - December 19, 2010

The literature indicates that UHP waterjetting does produce a profile on steel, although of a micro nature. Is this sufficient roughness for good adhesion of thin film primers (e.g. < 2 mils dft)?


Selected Answers

From Adrian Granda of n/a on January 11, 2011:
I agree with Barry Barman: waterjetting does not provide a "profile" and will not remove mill scale on new steel. You can use the pre-existing profile, however, after old coatings have been removed by waterjetting. The adhesion is no only issue with the pre-existing profile. It depends on both coating type and waterjetting level (WJ1, WJ2, WJ3 or WJ4). all this information must be addressed by the coating manufacturer.

From David Grove of Shaw Nuclear Power Services on December 28, 2010:
Seems no one asked the question, "What is the surface condition of the steel?" If it is new and has milscale on it, then no. If it was previously prepped where milscale had been removed, or had been allowed to rust so no milscale remained, then possibly, depending upon the coating type and the service. Ask the coating tech service representative for the specifics.

From greg sprinkle of certified coating inspections inc on December 27, 2010:
I think the very first question by far is the service environment. If it is to be mild atmospheric, power washing to UHP is more than accepted by many coating manufacturers that offer very surface-tolerant primers.

From Barry Barman of Barry Barman & Associates on December 16, 2010:
The short answer is no.According to the Joint Surface Preparation Standard SSPC-SP 12/NACE No. 5, waterjetting does not provide the primary anchor pattern on steel known to the coatings industry as “profile.” We use waterjetting primarily for recoating or relining projects in which there is an adequate pre-existing profile. The fact that the intended primer is thin (<2 mils)does not negate the need for a proper anchor profile. Consider that the primer is just one coat of the specified paint system and that profile depth should be approximately 25% of the total coating thickness. If there are concerns that a thin prime coat will produce pinpoint rusting when applied over a profiled surface, remember that coating thickness is measured as the thickness "above the peaks" - determined by subtracting the BMR (Base Metal Reading) from the measured coating thickness as described in SSPC-PA 2. In this manner there will be a nominal dry film thickness of 2 mils above the peaks. Regardless, the primed-only steel should not be left untopcoated for an extended period of time.

From David hennerbichler of Imperial Oil on December 15, 2010:
It really depends on the level of detail in the manufacturer's data sheet

From Adam Backhaut of Diamond Vogel Paints on December 14, 2010:
It will depend on the type of primer being used. Are you using an etch, epoxy, or 2k polyurethane primer? Make sure the primer “system” is designed for a direct-to-metal application. I would test one small area for adhesion with the current surface profile using the ASTM method (bear claw cross hatch). Also, don’t be afraid to call your paint supplier for assistance; they will be there to help you with technical support.

From Muhammad Iqbal of CV. Kharisma Selatan on December 14, 2010:
Philip A. Schweitzer in his book titled,"Paint and Coatings: Applications and Corrosion Resistance," wrote that profile depth should be approximately 25% of the total coating thickness. On the basis of a 6-mil coating thickness, the profile depth should be 1.5 mils; hence,if what Philip wrote is applicable and acceptable, then it is sufficient.

Please sign in to submit your answer this question    


Current PSF Question | Submit a PSF Question | Full PSF Archive

Safway Services
Your Access Advantage. QUIKDECK®

Provides safe, factory-floor-like working conditions. Can be engineered to fit almost any shape, structure or size. Modular platform easily assembled from just a few basic components. Excellent containment. Applications include vessels, offshore rigs and bridges.


International WorkBoat Show


NACE International, The Corrosion Society
Toss Out Your Paper-Based Training!

Discover a new, interactive way of learning with the first module, Safety Codes, Practices, and Standards, of NACE’s Industrial Coating Application eCourse.


Covestro Deutschland
Corrosion protection – one layer ahead

Pasquick® saves one layer of coating in corrosion protection projects – resulting in faster workflows and more cost efficiency for owners and contractors.


Axxiom Manufacturing
The Undisputed
Industry Leader.

Proven Innovation. Job Performance. Industry Training. Workplace Safety. Only Schmidt® abrasive blast equipment by Axxiom Manufacturing delivers it all!


Detail Masters
Overspray Removal

We offer professional, turnkey service and unparalleled quality!
Our process can save hundreds— even thousands of dollars. It's fast, environmentally safe and 100% guaranteed.


Advanced Recycling Systems
ADVANCED RECYCLING SYSTEMS (ARS)

Recycling Machines, Dust Collectors, Rapid Deployment units are time-tested and approved for the rugged industrial environment. Contact ARS today!
(330)536-8210


KTA-Tator, Inc. - Corporate Office
KTA-TATOR LABORATORY SERVICES

• Coating failure analysis
• Independent
  comparative testing
• Accelerated
  weathering testing
• Toxic metals testing
• A2LA Accredited
Contact: Cindy O'Malley,
at 412-788-1300 x180

 
 
 
Technology Publishing

The Technology Publishing Network

The Journal of Protective Coatings & Linings (JPCL) PaintSquare
Durability + Design Paint BidTracker

 
EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
MORE:      About PaintSquare.com   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us
 

© Copyright 2000-2016, Technology Publishing / PaintSquare, All rights reserved
2100 Wharton Street, Suite 310, Pittsburgh PA 15203-1951; Tel 1-412-431-8300; Fax 1-412-431-5428; E-mail webmaster@paintsquare.com