Dissimilar metals

["Robert H. Hughes" <robhughes100@domain.elided>]

Harvesters,

I had some aluminum bed rails made for my Scout II.  They will fit over
the outer and inner fenders to complete my fiberglass quarter panel
install.

In past digests, I remember people discussing some problems with putting
aluminum up against steel.  Can anyone explain this?  Is there some way
I can get around it -- by painting the contacting surfaces, maybe?

Thanks for any info.

Rob H.