Dan,

I don't know the specifics on the 18-2 track, but if it is anything like the H17 i got from you it is rivited through the lip with backing washers on the bottom of the lip.

Just as a thought, why not get a piece of 1/8" aluminum from the hardware store, and bed it in marine adhesive caulk on the bottom side of the lip, then use new longer rivets that go through the lip and AL piece creating a clamping efffect on the lip. If the holes are a little large, use the rivet casings to shim the hole size. The only down side is the AL would not be anodized.

The H17 is looking like new, sails should be here any time.

Mike