I've been using one of these for many years to do my airbrushing for model railroading. I pump a spare tire to 40 PSI and I'm good to go. One fill definitely will get you through a standard 3/4oz color cup of paint. Although obviously the pressure starts at 40 PSI and constantly reduces over time, but I'm happy as long as the paint shoots evenly and sticks! I've since bought a quiet $75 2 gallon 1/3HP hardware-store compressor and it's definitely nice to have an endless air supply with regulated constant pressure, but I still keep my Tire Adapter as a backup in case the compressor dies.