Is the container in good shape everywhere except in the bottom pan?
Have you considered using something like pop-rivets for a repair?
Cut the pan off, make a replacement pan, attach with pop-rivets to the
existing framework.
Do it this fall after the cooler is no longer in service.

Steve B wrote:
"Big Al" wrote in message
...
I have an 8,500 CFM side draft swamp cooler that is rusting out. The bottom
pan has a few rust holes through the sides under the pad frames.