A brushless, sealed motor will work well and not ignite solvent based materials.You need a pre-filter media to stop 60%-70% of paint residue and the slippery plastisol residues.The fan blades needs to be accessible and cleaned every 2-3 months and the filter media,depending on work load,every 1-3 weeks for exhaust efficiency. I use a commercial,inline ,10" diameter HVAC fan that has a variable speed from 620-740cfm and is exhausted through a 10" duct that is centered in a 25"Wx25"Hx25"D custom spray booth. I had a seperate 8'',adjustable duct fixed in the LLHC of the booth that draws air from the small attic in my shop so the fan doesn't drastically reduce warm ,shop air temps during the cold winter months and AC temps from the blistering summer air temps.