anodized aluminum compatibility

[hisilver]

So I'm working on a project and the materials are cedar and anodized aluminum.
This is for outdoors and within 5 miles of the Atlantic ocean.
I understand to use stainless fasteners in cedar.
I need some big lag bolts to run through some square anodized alum., do these need to be stainless steel
or will zinc plated steel be OK? Or neither? I'm unsure of what would be safe touching anodized alum.

Also the anodized treatment is only a surface treatment so cut ends will not be protected?
Thanks

 

[Tempest]

There are different types of anodize. Is it simple decorative anodize (extremely thin) or hard anodize?

And yes, cutting it will remove the anodize and expose bare metal.

I'm not sure of the galvanic corrosion conditions here but with a moist environment it's a possibility. Guns mate steel and anodized aluminum all the time.

 

[hisilver]

I don't know what kind of anodised it is. This tubing is for use in off shore fishing vessels for tuna towers and such. I've used it before and it still looks new 5 years later so I think its top quality stuff. Also about ten dollars a foot.

 

[PandaBear]

I wouldn't use zinc plated steel, eventually it is going to rust much worse.

 

[JetStar]

what you need to look at is where the metals fall in the galvanic series for your environment. Here is one for seawater.

http://www.corrosion-doctors.org/Definitions/galvanic-series.htm

 

[hisilver]

Thanks for the link. I think to be safe I'll also insulate the fasteners with paint and/or rubber or nylon washers.