Henry is giving you good advice regarding the danger....can you stand for your garage/house to be dismantled? Can you build the booth outdoors so it only blows up the plastic and studs?

I knew a guy who had his garage explode.....blew the garage door across the alley and it hit the house behind him. The garage wall moved about 6 inches sideways and the concrete floor cracked. The water heater pilot light lit off the charge.

Little box fans havent got much ooomph. Do some reseach regarding how many turns of air per minute that you need for a booth (how many times the entire volume is replaced). For a booth your size and 8 ft tall, you have 3072 cubic feet. A WalMart box fan probably moves 500 CFM so it takes six minutes to exchange the air!! That's not too good when you have a spray going...... also, the el cheapo fans are rated a some tiny back pressure....the filters add a bunch of back pressure.

Be careful.