cold galvanizing specs for notes for structural steel? 1

[delagina]

What notes do you use in your drawings for cold galvanizing due to field welding?

Something like this:

Field weld shall be repaired with Cold Galvanizing using blah, blah, blah...

 

[Teguci]

I usually keep it simple - "cover field welds with zinc rich coating"

It usually doesn't matter since its sacrificial. I just have that note on there so that the welded areas look pretty for the client right after installation.

 

[KootK]

If it's serious stuff, I call out metallizing. If it's less serious, I specify zinc rich paint in my plans/details and spec a product recommendation in my specifications.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[delagina]

I got this from galvanizeit.org.. Feel free to comment..

Repair damaged galvazined coating due to field welding with a zinc-rich paint. Zinc-rich paints must contain either between 65% to 69% or greater than 92% metallic zinc by weight in dry film. The coating thickness for the paint must be 50% more than the surrounding coating thickness, but not greater than 4.0 mils (100um).

 

[kingnero]

I have no experience with repairs using zinc-rich paint,
can somebody explain me why the gap between 69 to 92% is excluded (see above post) ?

 

[mike20793]

I would use the exact statement that SSPC uses in their specs.

 

[hokie66]

delagina,

I think the 65 to 69 is the zinc in the liquid paint, and the 92 is the zinc in the dry film. Depends on how it is measured.

 

[mike20793]

I believe the SSPC reference document is "Guide 14 - Guide for the Repair of Imperfections in Galvanized, Organic, or Inorganic Zinc-Coated Steel using Organic Zinc-Rich Coatings" but I really recommend picking up their entire manual as it contains a wealth of information on surface prep, painting, etc.