On Wed, 12 Jan 2005 17:18:39 -0500, "Joe"
wrote:

We use some decent flat head screws on our units and I've run into a strange
problem. When we tighten them into the aluminum housings, they hold a
galvanized plate in place. After about 10 minutes of being on there, they
are almost impossible to get off.

Have you tried any experiments with different screw materials?
Stainless? Brass?