The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Powdercoating galvanised steel

Galv steel that I receive for powdercoating comes in various shades - from dull matte grey to highly spangled shiny almost silver. All suppliers say that the galv isn't passivated - so why the difference?   Can you recommend a book on galvanising for associated industries - something that will give me an idea of the basic process as it may affect a secondary finishing process such as powdercoating.   Looking forward to a reply    

Richard Besant General Manager.
ESP Powdertech, Corby England
1999

---

Get in touch with the American Galvanizers Association. They have a number of free publications that are available online about galvanizing and its issues.

Hope that helps...

  
Craig Burkart
- Naperville, Illinois
1999

The condition you refer to is the development of the spangle in the galvanized coating. This is primarily a function of coating thickness and cooling rate of the coating after galvanizing (things like alloy content, etc, also have an effect). The american galvanizers is a good source of information in general, but you may also want to talk with the producing companies as well. If you are buying through a service center (or a mill) you may wish to specify the spangle for your operation. If you are painting or powder coating, a minimized spangle or no-spangle (dull grey) may be desired, but this will be determined by your needs.

ray szkola
- fabricated products
1999