I have about a 15 year old mastercool AD71 on my roof.

The bottom panel under the water tray and the side panel with the water inlet have rusted through (as in the water tray hangs, and chunks of the side tray come off in my hand).

I can replace the unit for about about $1150, or get replacements for about $320.

But i'm wondering if it would make more sense to get aluminum sheets to cut and bend, so they don't rust again.

Is this practical? And what grades of aluminum could i use, or how thick do i need. Heavier for the bottom than the side, i would think.