Whatever you do, DO NOT build your booth from cardboard!
This is probably illegal; I'm crossposting (SSSHHH!!) portions of the response I just wrote to Gigatron (Fred).
Spray booths are constructed for two reasons: to control inhalation exposures, and to prevent fires. In order to do the latter, spray booths are designed, constructed, and expected to perform as a system, not just individual components thrown together with the hope and prayer that a failure with one component will not affect any other. All the hazards of a system have to be identified and controlled, including those inherent with the system itself, and those that impact upon it. If they are not controlled, and the system fails, then the potential for catastrophic results is greater than if the system fails together as a complete, properly designed system. If a booth is cobbled together without thought to the hazards, then the potential for loss is greatly increased and includes loss of the system itself and everything that is directly or indirectly responsible for its operation, even the human element.
Cardboard burns. Period. It doesn't matter if it's flammable or combustible. Couple that with a range hood, bathroom, or other similar fan, and the hazard potential (or risk) increases exponentially. And as an anticlimactic statement, it also does not provide adequate structural rigidity or integrity. Your system fails. Completely.
I've only seen a couple spray booth fires in my career, and I can state emphatically that I'm glad they were designed and constructed correctly. The fires were contained and extinguished quickly, with no appreciable losses noted.
I've said this once or twice before, but if you want to build a spraybooth, do it the right way the first time. Make it a point to learn to not be satisfied with a toy...
Gip