@pastrygirlI have an Iwata SmartJet Pro (IS875) - http://www.iwata-medea.com/products/compressors/smart-jet-pro/
This isn't really high enough pressure. You can make do with it, but I have to pause after each row of cavities and let the pressure build back up. It's really great for spatter applications that use a lower pressure, but if you want easy whole-cavity coverage you'll need more pressure. If I do get the opportunity to upgrade, I'll give the IS875HT a go, unless someone on here has a better suggestion