Rust on the sunroof, and sunroof only. Metal experts??/

[Huw Powell]

> Stainless bolts on your sunroof would cause this, although a decent layer of
> paint should stop this, we make remote controlled submersibles and in any
> instance of different metals (ie in your case stainless, steel and zinc
> galvanizing) we try and insulate between the different parts, usually the
> best approach is to use nylon washers, or don't use stainless!!! Steel is
> much more forgiving but of course it will rust itself.

I beg to disagree...

"stainless steel" and "steel" are actually not dissimilar metals, just
slightly different alloys of the same ingredients, depending on the type
of stainless steel.

There's no zinc on a Coupe GT, either.  If there was, there'd be no rust
until the zinc was all gone, basically.

Two things suggest themselves to me - one, is that I have seen many 4k's
and coupes with rusty sunroofs, and clean roofs and hoods, etc.  It may
be more to do with the metal flexing enough to damage the bond of the
paint?  or perhaps the sunroofs are not painted as well as the bodies?

Also, of course, any time you go drilling holes to add bolts or screws,
you expose unpainted metal, which must be carefully treated and
protected to prevent rust starting there.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/