Thanks for the correction, unfortunately the 3 finishers I've been asking all say get a compressor and definitely not a turbine unit, but on this site it seems the opposite, but a really successful guitar refinished recommends a good compressor good gun and all the filters, water seperator a, and what not. Thanks I like hearing all sides
It really does not matter what you use for an air source so long as the air source is appropriate for the gun (turbine for a turbine spray gun, air compressor for an air compressor type spray gun) -- ultimately compressed air is compressed air just the same. An air compressor is as good an air source as any so long as it can reliably deliver the required volume of air and you have a suitable filter ahead of the spray gun to capture any water or oil that may be in the line -- and if you need really dry air then you can always install either a desiccant water trap or a drier (a type of dehumidifier for compressed air) inline to remove even more moisture. You will also want to install a regulator just before your spray gun to ensure proper pressure is maintained at the spray gun at all times (I typically run 90-100PSI into the hose and then drop that to ~40PSI at the spray gun with the second inline regulator). This allows me to get away with using a smaller and more flexible air hose for the final 25 feet while still ensuring adequate air pressure for the spray gun -- in fact, the ability to use a smaller and much more flexible air hose of whatever length I need or wish is one of the reasons I prefer air compressor powered spray guns over turbine spray guns when portability is
not a concern...plus an air compressor is useful for so many more tasks whereas a turbine spray gun is suited to just the one task. The nice thing, though, about air compressor spray guns is that you can pretty much attach any sort, quality, and size of spray gun to your air compressor you wish, even mixing and matching brands and types, whereas the turbine units are typically much more proprietary in nature with limited choices available for a given turbine air source -- an air compressor is essentially a universal air source so long as it can deliver the required volume of air at the required pressure for a given spray gun or tool.
That said, turbine spray guns are every bit as suitable a solution when the only task of concern is spray finishing, especially if portability is a primary concern, and I would never discourage anyone from choosing that route if such better serves their needs.
Be aware when buying a turbine spray gun that the number of turbine stages and the maximum volume and pressure a turbine unit can deliver will determine the upper limit as to how viscous a finish you can spray reliably (and some finishes do not tolerate much thinning) as does tip and nozzle size, just as the maximum CFM that an air compressor will deliver determines the same. With either solution, if you choose too small of a turbine or air compressor then you may not be able to spray some finishes (particularly thicker finishes), so it pays to buy into an appropriately sized turbine or air compressor to begin with (though it is possible to cheat a bit with an air compressor and a large tank, but it is much better if the air compressor is properly sized to begin with).
I also prefer the gravity fed HVLP spray guns, as you mentioned, as they are much easier to clean and break down when finished spraying for the day as they have a very simple path for the paint. Just do not let them go too long without a proper cleaning or you will regret it (I will always clean my spray guns at the end of the day or immediately if it will be more than a few hours until the next coat), but you can go several coats over the course of a day before you break it down to clean so long as there is good finish remaining in the cup (so no finish can dry) with most finishes. They also have a very nice balance in the hand when a hose is attached to them.