What kind of filter do I need for the enclosure of a 3d printer? I've heard alot about the need for ventilation when using 3D Printers lately.  Is there any special sort of filter that would prevent the toxic gases from leaking out of the printer while it's printing it's filament?  Is printing outside a solution while I build an enclosure?
For the most part, a consumer 3D Printer will only need proper ventilation when using potentially harmful materials such as ABS. (See duplicate question). If you're printing with primarily PLA, then you don't need to worry. I print mostly with ABS and keep my machine close to a window and I haven't experienced any issues.