oilspot

I forgot to explain in my earlier post how I fastened the mending plate to the wall.
Since the aluminum skin is so thin and no wood behind the aluminum, I used aluminum rivets.

Before I began riveting, I painted the plate and then put a good helping of silicon glue on the wall.  The glue will help hold the plate, as well as displace water to prevent galvanic action between the aluminum and steel.  

Then I riveted the plate into place, using a lot of rivets (the mending plate is full of holes) along the perimeter.  I didn't want the repeated manet pull to work anything loose...