Swamp cooler questions

I got a nearly new large swamp cooler today for $25. It needs new pads, and
has slight corrosion inside, nothing deep nor penetrating. The rest of the
paint throughout looks very good. It has a one horse two speed motor, and
is downdraft.

What type of paint would I buy to cover up the corroded spots? I have
already gone over them with an electric grinder with a cup knot brush, and
have the corrosion and flaking paint cleaned off. Do they make special
concoctions for swamp coolers?