I made these corner reinforcers to be used with 1/2" thick foil backed foam insulation to make a heated enclosure for my Prusa i3 MK2. You can get 4x8 sheets of the foam at most hardware stores. It's a little flimsy but reinforcing the corners makes a big difference. The corners are designed to be attached by pushing a zip tie through the outer piece, through the foam, through the inner corner piece, and back out through the second set of holes, and zipped tight. I used PLA which might get a little soft in the upper corners, but doesn't have a huge amount of force on it so I haven't seen any distortion.

The insulating foam does a good job retaining the heat produced by the printer and I've printed up to 65 deg C with this setup although I start to worry about the electronics a bit at these temps. Oh also, if you preheat the chamber very much it'll mess with the PINDA (if you're using a Prusa, the bed sensor otherwise), you'll want to be ready to adjust the live Z height adjustment to get it back down to the bed.

I reinforced the edges with foil tape and taped a lexan window into the front. I planned on making a zoomy set of doors to go on it with the lexan, but it's so easy to just lift off of the printer that I never bothered.

One last warning: Any PLA parts inside the chamber will get soft if the temp gets very high. I dropped a roll of filament on the bed after my spool holder got soft and gave up...

Prusa

Prusa Mk2

No

No

Regular settings for whatever material you use. I printed mine solid but they probably don't have to be. A couple outer shells would probably be plenty although they're pretty thin to begin with. No supports needed.