This is a bracket to hold a Firestop, which will attempt to put out any fires that reach it. This is a safety device meant to be placed over stoves, but it works well for my Ender 3.
The mount for the firestop is meant to be magnetic, but it's not necessary. In either case, I added a small shelf above the device that can be used to secure a washer for magnetically mounting this (really just makes sure it doesn't slide out).
Very little infill is necessary. The profile is triangular so it's fairly stuff. It's designed to be printed on it's side with no supports. Use two M4 machine screws and t-nuts to secure it to the Ender. I'd also recommend PETG or something that'll handle the heat a little better. If the fire does reach this thing, you probably want it hanging in there for a few seconds. I tied a piece of safety wire to mine so that if it did melt, the canister would drop and still be suspended.
firestop_mount.STL | 57.1KB | |
firestop_mount_no_washer_shelf.STL | 50.3KB |