Just finished making a cooler for the C9.25.
It certainly is NOT pretty!...But it works GREAT! It's made out of all sorts, mainly cardboard, plenty of masking tape, bitsa 3/4" poly pipe...whatever I could lay my hands on really!
Used a 3" dia 12V fan & made a filter for it as well. At the exit point it blows a cigarette lighter out. It's 'hurricane Alley' in that OTA!!
I won't post a pic, you'll all laugh at me!
Cost Zilch. Well thats not quite true, I paid 10 bucks for the fan 2 years ago.