Yeah ... I just know what I read.

Here is the explanation I read:

"The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a "passive" film which resists further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen. Once the layer has formed, we say that the metal has become "passivated" and the oxidation or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. per year).

Unlike aluminum or silver this passive film is invisible in stainless steel. It's created when oxygen combines with the chrome in the stainless to form chrome oxide which is more commonly called "ceramic". This protective oxide or ceramic coating is common to most corrosion resistant materials."

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*From*: "George Lendich" <lendich@aanet.com.au>
*Sent*: Sunday, July 18, 2010 5:17 PM
*To*: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
*Subject*: [FlyRotary] Re: Tie Down Hardpoints

* *Thomas,
Well that's a new one on me.  Sound to me you might be getting confused with Anodized Aluminium. I know lower grade stainless can pit because of electrolysis in extreme environments and because of that they use 316 ( marine) grade. I know carbon grade stainless can rust
However if anyone can confirm this I would appreciate hearing further about it.
George ( down under)

    I think I want to stay away from the stainless because it will be
    completely enclosed in fiberglas.
    Stainless needs to be exposed to an oxygen environment in order to
    for that protective layer (chrome oxide) that prevents further
    oxidation.

    At least that's what I've been told/read.

    ------------------------------------------------------------------------

     Thomas,
    I agree with Tony, use something that won't rust, nothing looks
    worse on the exterior of a plane. Maybe consider stainless steel,
    I use it on everything.
    George (down under)

        Hey Tony.
        Now I'm looking for the tie down hardpoints (either parts or
        specs) referenced on page 25 of the 'A' kit manual.

        I have not found them in the drawings either.

        They say thay are Cad plated steel. I can have them made but I
        would be guessing.
        Maybe .125  3" x 3.5" plate would suffice with a threaded
        steel bushing welded to it and then plated.
        I figure the bushing threaded/tapped 1/4" x 28 could be 5/8"
        material ... maybe. ... or 3/4".

        Any Ideas?

        Thanks.

        T Mann