John K Jordan
With no dryer you can expect to blow water on your work.
I use several things to keep water out of the lines. One, I made a gravity trap from brass tubing (with a drain valve on the bottom) to catch liquid water that condenses in the line from the tank. Next on the line is a cheap water separator to catch liquid water that makes it past the trap. Then a desiccant dryer absorbs any water vapor that gets that far. The air at that point goes thru a regulator then to the shop air plumbing.
I also have gravity water traps at all the air outlets but have never seen a drop of moisture from one so the other stuff must be working.
If I'm using the plasma cutter I use a second, smaller disposable in-line desiccant dryer at the point where the house enters the machine. For insurance. Plasma wants dry air.
If I had just one thing and no money I'd add a cheap centrifugal water separator. If dry air was critical I would get a good industrial desiccant dryer. I bought mine through Amazon. It has cartridges that need to be replaced periodically but I cheat, take the cartridges apart, and replace the desiccant with dry desiccant than dry the wet desiccant in the oven.
I suspect you could get by on the short term with a disposable desiccant dryer just before your spray gun. (I get them from a local Northern Tool store.) That is, of course, after draining any moisture from the tank and blowing out the lines.
Another thing recommended is to put any separator/dryers at least 20 ft from the tank. The long line allows the air to cool and most of the water vapor to condense and be caught in a gravity trap and/or a separator.