<<Has anyone tried aluminum on aluminum for the hinge and hinge pin combination?  I am considering using a tig welding rod to eliminate the galvanic corosion from the steel on aluminum. >>

I'm not sure what the application is here.  As a control surface hinge you would probably end up with galling by using aluminum on aluminum.  I am using welding rod, but of the stainless steel variety, in all of my hinges.  Its larger diameter has eliminated the play, vibration, and wear inherent with the standard MS hinge and MS hinge pin combination.

Chris Zavatson
N91CZ
360 std