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

 

Download our free ebook on Abrasive Blast Cleaning

Problem Solving Forum

| More

November 11 - November 15, 2013

I have galvanized steel in direct contact with powder-coated aluminum in an outdoor exposure. The galvanized steel is corroding. What is the best way to remedy the situation?



More items for Quality Control


Selected Answers

From Robert Cameron of Belzona Houston on November 22, 2013:
There are two-part epoxies available that are tolerant to surface contaminants. I would remove loose contaminants with hand tools and even refer to SSPC-SP 11, Power Tool Cleaning to Bare Metal, if possible on the galvanized section (no need to knock off the galvanized layer if it is tightly adhered). Then mask the powder-coated area, and apply two coats of this two-part, surface- tolerant epoxy.

From Karen Fischer of Amstar of Western New York, Inc. on November 19, 2013:
Though there isn't much information here as to what kind of structure this might be and how the two materials are connected (fixed or movable), my first inclination would be to isolate the two dissimilar metals with a neutral, non-reactive material of some kind to eliminate the direct contact between these two metals. Clearly, the galvanized metal is reacting with the powder-coated material. I don't know what kind of structure this is, but some type of rubber or plastic spacer may be enough to stop this reaction. Painting of the galvanized metal may not provide sufficient isolation, especially if the connection is movable. Repair and re-galvanizing the corroded area can then be accomplished.

From Carl Thompson of Hill Brothers on November 11, 2013:
I would tape the powder-coated aluminum where it meets the steel. Aluminum is amphoteric and can be attacked by either acid or alkali. Treat the galvanized steel with a 20% solution of phosphoric acid. Wait 15 minutes, then wipe the rust and corrosion away. If some corrosion remains, repeat the process. When cleaned, neutralize the galvanized steel with a very dilute solution of ammonia. You should see a white residue on the surface . This is an oxide of phosphoric and should help keep further corrosion away. Any holes developed from corrosion should be filled with a metallic, 2-part epoxy putty. If painting is desired, brush away any loose white powder with a stiff copper brush and proceed. To prevent any galvanic reaction between the aluminum and the stainless steel, painting the galvanized metal would be preferred.

Please sign in to submit your answer this question    

Tagged categories: Aluminum; Corrosion; Galvanized steel


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

KTA-Tator, Inc. - Corporate Office
KTA Online
Instrument Catalog

• Any Manufacturer
• Any Instrument
• Any Time
Visit www.ktagage.com
Or call 800-582-4243


Elcometer, Inc.
Durability & Design meet
Performance & Reliability

Elcometer 319 Dewpoint Meter
View the technical data on the Elcometer Dewpoint meter.


SSPC: The Society for Protective Coatings
http://www.sspc.org/

Join SSPC and Enhance
Your Career !


U.S. Zinc
Helping the World Work

We offer custom grades and packaging of zinc dust, oxide, metal and fines, U.S. Zinc provides direct shipping to locations worldwide. U.S. Zinc – Helping the world work


Termarust Technologies
Termarust (HR CSA) Chemically Stops
Active Corrosion

Arch truss treated with Termarust's (HR CSA) in 2003. This steel arch bridge is rust free on all surfaces including the crevice corroded joints and connections.


Fischer Technology Inc.
MP0R with rotating display screen

Automatic rotating display screen just like your smart phone. Click for Video
Call 800-243-8417


Montipower, Inc.
The MBX Bristle Blaster

Get a 2.7 to 3.3 mil profile and a Near White Metal Clean. For info visit www.mbxit.com or call 877 629-8777


DRYCO
Control the Tank with DRYCO

Temporary climate control equipment. Dehumidifiers,
Heaters, A/C, Power, More…
Toll Free: 866-379-2600


Armakleen Company, The
ARMEX when nondestructive cleaning is critical

The gentle physical propriety of baking soda but yet aggressive cleaning ability is what makes ARMEX the only choice for nondestructive abrasive blasting.


AGC Chemicals
I-65 Arch Bridge Gets a Facelift with LUMIFLON®FEVE Coating

LUMIFLON based coatings can last up to 30 years without fading, offering a low-maintenance solution that retains color and gloss and can be field-applied.

 
 
 
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 2000-2015, 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