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

 

Problem Solving Forum

| More

July 7 - July 18, 2010

If I apply 140 microns of inorganic zinc to a steel substrate with a 75 micron profile, is there any concern about cracking of the primer during storage, shipment, and erection of the structure, or with field-application of a topcoat?


Selected Answers

From OM PRAKASH JAT of TECH INTERNATIONAL SHARJAH HAMRIAH UAE. on March 5, 2015:
In general, the greater the surface profile, the better the coating adhesion will be. One exception to this rule appears to be inorganic zinc silicate primers, which tend to split (lose cohesion) when the anchor profile exceeds about 67 microns (2.5 mils). This may be caused in part by attempts to increase coating thickness to cover profile peaks. A 100-micron DFT is enough to get very good corrosion protection, and the top coat will need a mist coat to avoid pop or trapped air onto the surface which may be the cause of pinholes. Inorganic zinc silicate primers are well known to be sensitive to excess thickness. Follow the guidelines on the manufacturer's technical data sheets.

From Marco Antonio Alvarado Meneses of Sherwin Williams Perú on August 13, 2010:
It depends on several things. The most important, I guess, is the manufacturer's recomendation about this issue. Environmental conditions are also very important, including maintaining appropriate minimum relative humidity. Check all these. Geometry of the surface is very important because DFT may be higher than data sheet recommendations in corners, angles, etc. A good painting system is inorganic zinc rich, followed by an epoxy two pack and an aliphatic acrylic polyurethane.

From Tolga DIRAZ of MITAS Group on July 16, 2010:
There are two critical questions that should be asked? - What type of inorganic zinc coating, i.e., alkali, alkyl, or reinforced, is to be applied to a steel surface? - What are the enviromental conditions for proper cuirng? - What is the geometry of the surface, i.e., flat or with some irregularities such as corners and sharp edges? As most of you may agree with me, painting an irregular surface can definitely create some problems that may yield cracking of inorganic zinc type coatings.

From Suresh Chandra Gupta of Bharat Heavy Electricals Limited on July 9, 2010:
Application of an inorganic ethyl zinc silicate coating of 140 microns to a substrate with a 75-micron surface profile would not pose any problem during storage, transportation, and erection, provided the substrate is free from grease, oil, and dust, and is shot-blasted to Sa 3 or Sa 2.5 minimum before application of the coatiing. (Eds. Note: Sa 3 is approximately the same as SSPC-SP 10, and Sa 2.5 is about the same as SSPC-SP 10.) The paint should have been properly mixed and applied by air spray, with recommended RH of 65% minimum. The curing of the coating must be checked by MEK rub test as per ASTM before dispatch. If these conditions are observed during application, no problem would be expected even on prolonged storage. However, if it is required to be top- coated, then a mist coat before application of the top-coat is recommended to enhance the adhesion between the coats as well as life of the coating. The most important parameters during the application are surface preparation and the application method.

From Pedro L Castillo M of Ancel C.A. on July 7, 2010:
The profile is not the concern. It is possible that high DFT of IOZ can cause cracking, because the Zn content in the film may be too high. We hope that a DFT of about 100 microns is enough to get very good corrosion protection and the topcoat will need a mist coat to avoid pop or trapped air.

From Jeff Croll of Northern Corrosion Technologies on July 7, 2010:
It depends upon the "inorganic zinc" as well as the conditions of application and the recommended film thickness by the manufacturer. Some products labelled inorganic zincs are not silicate inorganic zincs but are called inorganic due to certain modifications that allow for fast recoat when the resin or binder is actually an epoxy. The environmental conditions play a part in that too little moisture in the air will prevent the zinc from fully curing. Generally, most manufacturers' inorganic zincs are not high builds and thus there is the possibility of splitting when topcoated if the thickness of the zinc is too high. It is very important to follow the recommendation of the manufacturer as regards environmental conditions, film thickness, and profile depth and angularity when applying inorganic zinc.

From Tom Schwerdt of Texas Department of Transportation on July 7, 2010:
Properly applied, most IOZ coatings on steel will have no cracking problems associated with a DFT of 140 microns over a 75 micron profile. Our specifications allow nearly twice that DFT for shop-applied IOZ, and we field-apply a topcoat an acrylic topcoat a year or more later with no issues.

Please sign in to submit your answer this question    


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

Advertisements
 
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
 

 
Graco Inc.
 
Graco EcoQuip 2: Experience the Difference
 
While others claim their equipment is the same, none of them compare to Graco’s EcoQuip 2™ Vapor Abrasive® blasting line. Visit graco.com/ecoquip to learn more.
 

 
Tarps manufacturing, Inc.
 
QUALITY MADE IN AMERICA —Available near you!
 
CLICK to get a behind-the-scenes look at how Tarps Manufacturing makes the highest-quality tarps right here in the USA — available nationwide.
 

 
SSPC: The Society for Protective Coatings
 
http://www.sspc.org/
 
Join SSPC and Enhance
Your Career !
 

 
SABRE Autonomous Solutions
 
Quality
 
The ALPHA1 provides a consistent finish day-in
day-out; job to job.
 

 
Bullard
 
Upgrade with the Bullard GenVX
 
Click here for your blast helmet.
 

 
Sauereisen, Inc.
 
SewerGard® 210XHB
 
• 300 mils in a single coat by plural component equipment
• Fast Setting
• 100% Solids Epoxy
• Chemical-resistant barrier for municipal wastewater environments
sauereisen.com
 

 
BASF
 
New resins from BASF will have metals loving water!
 
Excellent corrosion resistance, low VOC, high gloss, thin films www.basf.us/industrialcoatings dpsolutions@basf.com 800-231-7868
 

 
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
  •  

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

     
     
     

    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 (Updated 1/8/2018)   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us