No registration, no passwords; no pop-up ads -- just aloha, fun, & authoritative answers.
As an eBay Partner & Amazon Affiliate we receive compensation for qualifying purchases.
Home /
Search 🔍
the Site
pub  Where the world gathers for
plating, anodizing, & finishing Q&As since 1989


What does iron phosphate do to hot dip galvanized steel

I have some steel that was HDG then powder coated. The powder coater said that he "sealed" the material with an iron phosphate spray, rinsed, then powder coated. Five years later, the powder coating is flaking off and the material is all rusted with only traces of the zinc left on it. Something has eaten the galvanized coating. Any suggestions? Thanks

Tim Lockhart
Sales manager, hot dip galvanizer - Orlando, Florida, USA
October 30, 2008

November 4, 2008

Hi Tim,

I'm not sure for what you want suggestions. Why the HDG corroded? Why the paint fell off? What would be a better pretreatment system?

Five years of protection may be all that is expected for this combination of pretreatment, paint and exposure conditions. Without more details, it's hard to provide a specific answer.

George Gorecki
- Naperville, Illinois

The attached is a picture showing the galvanized coating and the rusting of the steel.

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
Consult'g, Train'g
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"