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howardwheeler's avatar
howardwheeler
Explorer
Apr 16, 2017

Galvanic corrosion when fastening aluminum

I'm getting ready to screw together my three panels to my RV roof. I'm making a Z bracket out of two angle aluminum pieces so I need to fasten the aluminum to the aluminum frame of the panel, fasten the two "L" pices of my bracket together to make the Z, and last I must screw the aluminum brackets down into my roof. Should I use stainless fasrteners or galvanized or something else? I've been planning on stainless but I don't want it over time to corrode the aluminum. Especially I want to protect the panel frame.

10 Replies

  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Apr 17, 2017
    howardwheeler wrote:
    Sorry, but what is a URA type primer?


    These are todays two part primers that cure and seal the underlying structure.

    they usually come in two part kits. at you local auto paint stores
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Apr 16, 2017
    I buy SS bolts, screws, etc from Bolt Depot and they carry 18-8 and 316 SS. I buy 100 at a time and have plenty left over for other projects. It doesn't take very many from local stores to equal the cost of 100 from Bolt Depot, but you can buy smaller quanities.

    Absolutely no issue with using SS to attach my aluminum frames.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Apr 16, 2017
    Fastening Aluminum to aluminum or to non-metallic,, Use aluminum.. The closer the metals are to each other THE LESS galvanic corrosion

    Alternative, depending on how strong the bonding needs to be NYLON

    However, if they need to be electrically bonded.. Or IF A STRONG PHYSICAL bond (Which I suspect is your case) use aluminum.

    You can also insulate the bolt from the panels, and still do electrical bonding.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Apr 16, 2017
    I use nickel base anti sieze. 316 stainless is much less apt to white powder aluminum than either 18-8 or 304 grade stainless. But my stuff exists in a tropical sea shore environment. I have had aluminum based Never Sieze turn black. So I use nickel.
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Apr 16, 2017
    enblethen wrote:
    Use stainless!
    Suggest using oxidation compound between aluminum and on fasteners.


    X2 .. I'd dip each piece into a good 2 part ura type primer. and assemble wet.
  • enblethen's avatar
    enblethen
    Nomad
    Apr 16, 2017
    Use stainless!
    Suggest using oxidation compound between aluminum and on fasteners.

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