Whilst I agree with what you are saying, that would be totally impossible in a small and dirty Mechanical Workshop like mine, Paint Booth it is not, and it is not big enough for a dedicated Paint Booth to be built inside.
There are plenty pic's of my Paintwork learning curve in this thread start at Page 19 post numbers 361, 362, 366, 369, 370, 376, 382, 383, 393, 412 & 424
#412 are the C Class Panels, and #424 the S Class bits, these are straight off the Gun, no polishing and messing with using my latest learned techniques, (called experience I guess), and the Extract Fan and Devilbiss Clear Gun
Night and day compared to all the messing around I had flatting and polishing to get the Trunk, Roof test piece, and Right Doors looking good
I have got pretty good and repeatable results now, and the odd few dust nibs I do get are all but invisible once flatted and polished.
My latest efforts since installing the Extract Fan have been good enough to bolt straight on the Cars without any polishing, just the odd one or 2 nibs that can be flatted and polished out next Summer
The Fender and Sideskirt on Mels C Class look perfect, as do the Sideskirts for the S Class, without the extra time flatting and polishing I had to do on the Trunk Lid and the 2 Right Doors
These successes since fitting the extract Fan confirmed my suspicion that the particles were airborne and clinging to the lingering overspray, which settles on a freshly painted panel.
I now apply the Clear coat, and as soon as it's applied on goes the big fan, which is above panel level, and out goes the overspray and clinging dust ................. Sorted
The only other problem I had was "orange peely" Clear Coat which needed a lot of time consuming flatting and polishing, and that was caused by my being over cautious and applying time between coats was too long, and also too many coats.
I now give my panels 3 good Clear Coats, with 10 - 15 minutes between coats, depending upon temperature, and it works a treat
Devilbiss Gun purely for clear coats also helped.
It's about the best I'll get now without building a (much) bigger Workshop, with dedicated Spray Booth.
Remember, this is a 17 year old S Class, it will look really good when all Panels are finished and some flatting polishing done
I'm not and never will be a "Custom Show Winning Painter" but I do now have the skills and equipment to make a well above average job of my Cars as and when Paintwork is required
I'm hoping I may get the Front Bumper done this weekend
Cheers for now, Dave