zinc plated rusting

[Billgas]

What is the expectation of zinc plating preventing rust on exterior hardware?

I have some hinges that are rusting after 8 months....

 

[JStephen]

Zinc plating is pretty much to make the part look good until it is sold (or for interior use). For better corrosion resistance, use galvanized (much thickner zinc) or stainless steel.

 

[swall]

It depends on the thickness of the zinc and presence or absence of a supplemental treatment, such as a chromate. What kind of environment are we talking about?

 

[Billgas]

Exterior area in a mechanical courtyard (cooling tower moisture) in the Northeast (finally it is getting warmer...)

 

[CoryPad]

Without specifications covering zinc plating thickness and presence of conversion coating and topcoating, your experience seems typical. On the other hand, if you have a minimum zinc thickness of ~ 9 micrometers, with a thick chromate conversion coating and a polymeric seal/topcoat that is ~ 5-10 micrometers, then you could get 5+ years.

Regards,

Cory

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