About jlv's comment...

I have a 5hp 21 gallon compressor, and just found that it's not quite enough for my new HVLP paint gun. It's impossible I get a new compressor at this point, won't another air tank in-line with the output boost the CFM?

I realize the safety concerns, but if I used a tank rated for the pressure, isn't this an option?

I'd like to hear if anyone has done this. If so, what are the low cost solutions for the second tank.

Thanks!