I have two projects that need some foam insulation.

The first is my 3D printer could use some so that it can heat up faster and maintain hotter temperatures consistently. I plan to cut some panels to sort of put around it. Just feels a bit better than a blanket like most do.

The second is the one I am more curious about. I have a window I leave slightly open for kitchen exhaust. I would like to upgrade a bit and put a strong Duct fan pulling hot, steamy, and oil filled air from a few spots in the kitchen outside. My stoves range does not have exterior venting so this is me sort of upgrading it.

I rent so I cant do invasive solutions that would result in a "properly" installed duct.

I am essentially needing to know a few things about Pink NGX foam:

1. Is it reasonably easy with respiratory protection to carve out a rough hole for the duct with a jigsaw, jabsaw, etc?
2. Is it ok for it to be exposed directly to rain? If not I will probably put tin foil over it or otherwise coat it. Solutions appreciated.
3. Is it ok for it to be exposed to the same air I breathe without drywall blocking it etc? It doesnt like shed toxic particles while just sitting there right?
4. It is flame retardant but not completely. So it would take a significantly strong fire to be able to turn this foam into fuel right?

If I should be looking into a different foam let me know.

FYI in the past have just used cardboard wrapped in tin foil for adapting an AC Unit to a window. It worked decently.... But obviously it could be improved. Curious what yall do when you need to send something out of a window.