Galvanic Corrosion Questions

sub3marathonman
sub3marathonman Solar Expert Posts: 300 ✭✭✭
in Advanced Solar Electric Technical Forum #1
I haven't really seen this discussed much other than in relation to grounding a solar panel. I'm still wondering a bit about that aspect though too. I bought the grounding lugs from NAWS, so I guess it is going to be OK.

What I am wondering is how much of a problem it is installing an aluminum mounting bracket with a stainless bolt. Or the aluminum rails with stainless bolts. It seems that under poor conditions (such as salt water spray) this would lead to problems. However, since there must be moisture present before the corrosion can happen, if it is sealed with roofing sealer or some other coating would that be enough?

Has anyone had a system long enough to see the effects of galvanic corrosion? I am wondering what time-frame it takes to cause a problem.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Galvanic Corrosion Questions

    In the Los Angeles coastal area, mill finish aluminum windows, last about 10 years. I installed bronze anodized replacements, that had 20 years, and looked good. I've seen thin/cheap/rushed anodized aluminum last a little longer than 10 years before it gets ratty looking. The thicker the anodized coat, the better aluminum lasts. I've heard Stainless & Aluminum are supposed to be OK, but I have no experience with it.
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  • marks
    marks Registered Users Posts: 17 ✭
    #3
    Re: Galvanic Corrosion Questions

    Having completed my installation more than a year ago, I'm a bit rusty on the specifics. However, I too had this concern and located a web site that provided the info on how various metals would respond to each other. Naturally the different types of SS have different characteristics, and I didn't know what grade of SS that the bolts were. My main concern was with the SS bolts that mount the rails on to the aluminum stand-offs, and thus I located a thread compound made specifically for aluminum and SS. Hope this helps.
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