PaintSquare.com
Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site

 

Advertisement

PaintSquare


Problem Solving Forum

| More

November 7 - November 13, 2011

What is the best method for preparing newly galvanized steel to be overcoated with an epoxy system?

More items for Coating Application


Selected Answers

From Priya Samaroo of ftfarfan ltd on December 9, 2011:
It must be cleaned properly before applying an appropriate industrial coating. If the surface area has deposits, it must be cleaned with a heavy duty degreaser, and then you can use a direct-to-metal, water-based industrial paint.

From Adrian Granda of n/a on November 15, 2011:
     Galvanizing needs a lot of attention. Normally, you need a low profile to cover with an epoxy. I recommend  cleaning with SSPC-SP 1, then SSPC-SP 2 sanding with a sand paper number 100. Then you can apply a universal primer epoxy with appropiate adhesion to galvanizing.

From Kishore Kumar K R of Nukote on November 9, 2011:
     Degrease, then sweep blast to 20-25 microns.  Prime with suitable primer before applying an epoxy coating.

From Mohamed Ahmed of ELNG on November 15, 2011:
Hand abrading.

From boris vidic of CIS on November 14, 2011:
     Based on many situations on ships, I  recomended just a light sanding and applicastion of an epoxy holding primer. If you like, you can add a cosmetic final top coat.

From bichu rb of nsh on November 11, 2011:
     It's not required to blast galvanizing.  Just leave it if there are no defects. If there is any damage, we can touch up with organic zinc or surface-tolerant epoxy.

From frank crews of quality contractors and painting on November 7, 2011:
     Wash with a vinegar-water solution or use a light brush blast of the surface.

From James Albertoni of CA Department of Water Resources on November 14, 2011:
     Check out SSPC-SP 16. It's the new surface prep standard for galvanized and non-ferrous surfaces.

From William Feliciano of NYSDOT on December 19, 2011:
     Galvanizing may likely have been chromate-quenched to prevent white rust staining. Chromate is a definite adhesion killer. This must be removed. The point of brush blasting is to remove zinc oxides only, not to remove the galvanizing, only to etch it. Finally, allow no more than 1 hour between the brush blast/abrading and priming. Otherwise, zinc oxides will form again and impede adhesion. Polyamide epoxies are good primers. Apply at the lower allowable dry film thickness, then use a compatible topcoat. Why two coats? In our experience, pinholes and holidays in a single coat can allow moisture through, which will trigger the galvanizing to convert to oxides, which then blow out the paint system. I wouldn't paint galvanizing unless I absolutely had to. It's wise to wait two years (if you could afford that) for it to develop a zinc carbonate finish, which is very stable and a good substrate to paint.

From Carl Havemann of www.corrosioneducation.co.za on November 23, 2011:
    Degrease with a water-dispersible degreaser to 'waterbreak free' then sweep blast with garnet (fine grit), making sure the  blast operator is experienced. Can Lee tell us why he does not recommend abrasive blasting new galv surfaces ?

From Roy Bradley of Laing O'Rourke on November 17, 2011:
     It is extremely important to degrease new galvanized surfaces, which seems to have been missed by most respondents. After thorough degreasing, apply a mordant solution, then apply the epoxy direct. Alternatively, after degreasing, blast clean with a non-metallic abrasive to a profile between 20 to 30 micrometers.

From Lester Wienert of Wienert Mfg. Co. on November 14, 2011:
     Galvanized steel has good corrosion protection except in a polluted environment, where an epoxy coating may be in order. I have seen some aluminum paints actually cause corrosion - more than if there were no protective coating applied at all. I have had exceptional durability with properly formulated (corrosion inhibitor plus zinc dust ) water-thinned acrylic emulsion paints. Durability on iron water tanks is over 25 years now, and durability on galvanized steel quonset shows no peeling and very little weathering after 25 years.

From José Avendaño of Testers y Multimetros 2011 CA on November 11, 2011:
     Clean according to SSPC-SP 1 and apply a surface-tolerant epoxy primer.

From Lee Edelman of Independant on November 7, 2011:
     Galvanizing is a protective coating, and I recommend leaving it alone if there are no defects. If the specification calls for overcoating galvanized surfaces, there are several types of galv prep that can be used. I do not recommend abrasive blasting new galvanized surfaces unless specified.

Please sign in to submit your answer this question    


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

Advertisements
 
Industrial Vacuum Equipment Corp.
 
Hurricane Vacuums
& Dust Collectors
 
Vacuum and dust collector hose, filters and related accessories.
IndustrialVacuum.com
 

 
SEMicro Division, M.E. Taylor Engineering, Inc.
 
Coatings Adhesion Testers
 
The PATTI® accurately measures the bond strength between coating & substrate. Outfitted properly, the surface can be rough, porous, or curved & >10K psi strong!
 

 
SABRE Autonomous Solutions
 
Productivity
 
Personnel are free to do other tasks while the ALPHA1 does the “dirty work”.
 

 
Strategic Materials Inc.
 
Crushed Glass Abrasives
 
TruAbrasives™, a clean crushed glass abrasive superior to other abrasives for performance, health, and environmental benefits.
 

 
Abrasives Inc.
 
Need more MAGIC around?
 
Black Magic® is a premier solution for abrasive blast media. Stop by our new website & find out how you can get more Magic. www.AbrasivesInc.com 800-584-7524
 

 
Monti Tools, Inc.
 
BRISTLE BLASTER® – THE ORIGINAL ONE
 
  • Abrasive blast with a power tool
  • Remove corrosion, mill scale and coatings
  • Cleans & roughens
  • Meets SSPC-SP 10 / NACE No. 2
  • Profile up to 4.7 mils
  • ATEX Zone 1
  •  

     
    CS Unitec
     
    Remove Coatings, Corrosion & More!
     
    For metal & concrete. Scalers, scabblers, deck hammers & scarifiers. Safe for hot work zones. Call our specialists: 800-700-5919.
    Demo videos at www.csunitec.com.
     

     
    Vector Technologies Ltd.
     
    The Original Performance Proven Vacuum Solutions
     
    VecLoader® 616 Double Dump, Continuous Vacuum, 170 HP w/ 2,400 CFM & 28” Hg. 33% More Efficient than traditional vacuum systems! Choose Vector for the most powerful and the most reliable trailer mounted vacuums in the industry! Email us at: inquiry@vector-vacuums.com or call us at: 800-832-4010
     

     
    US Minerals
     
    POST-HARVEY: OPEN FOR BUSINESS
     
    U.S. Minerals Galveston, TX and Harvey, LA plants are open for business. Abrasive products are dry and ready to blast. Connect with a sales rep at BlackDiamondAbrasives.com.
     

     
    RBW Enterprises, Inc.
     
    Robotic Blasting and Painting
     
    When using the FasterBlaster and FasterPainter, blasting and painting can be conducted simultaneously. View the video for a full explanation of the operation.
     

     
     
     

    Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

    TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL webmaster@paintsquare.com


    The Technology Publishing Network

    Durability + Design PaintSquare the Journal of Protective Coatings & Linings 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