Corrosion Protection of Residential Wrought Iron Fence

[jdmm]

I want to construct an iron fence close to a beach around a house. The soil is sandy and has a high salt content. I want to minimize maintenance on the fence. Other than a zinc based primer can the fence be protected with sacrificial anodes such as zinc attached to the fence? I was thinking of a blob of zinc on each panel such as is done to protect outboard motors. Alternatively, could you use cathodic protection by applying a DC voltage from say a solar panel?

 

[Metalguy]

I'd use a combo of heavy galvanizing, topped with some good coating or paint. Then use Zn or Mg anodes, or an impressed current system as you wish. The coating will greatly reduce the current demand of whatever protection system you use.

 

[jdmm]

Thanks metalguy,

Could you attach the Zn anode to the bottom of the metal fence with a screw like is done on outboards? Is there a relationship between weight of iron protected vs weight of Zn anode?

 

[Metalguy]

Yes, you could simply screw the anodes on, esp. if you use a lot of small ones. The problem would be periodic replacement, but they would last a long time (years) if you coat the cathode (the fence).

I don't know how one would calculate the amount of Zn or Mg required-depends on many factors. But even small anodes will protect if the spacing isn't too great.