For those of you interested in making coroplast pans for your CN, if you have rats that chew like mine, they might destroy them in no time flat. To solve the problem, buy some "undersill trim" or "utility trim" from Lowe's or Home Depot. It's in the vinyl siding area. You just cut it to length and slide it over the edges of the coroplast. Problem solved. At least for me, they do not chew it at all, but when I tried just the coroplast, they destroyed it in no time flat. Here's a link to what it looks like: https://www.randgsupply.com/Warehouse/Exterior/vinylsiding/vinylsidingtrim.htm
(undersill trim). If you don't like how it hangs down so low, you can easily cut the notched edge off. I leave it the way it is. It doesn't look bad to me at all and offers greater protection. I put the low hanging edge on the INSIDE of the cage.
Hope this helps anybody who thinks coroplast would not work for them. My rats are big chewers, and this has been an inexpensive solution to several problems. IF they start to chew the trim, which for me is rare, it's very easy to pop off the old trim and replace it before it gets to the coroplast. But like I said, they rarely even nibble it.