Question (WOODWEB Member) :
I'm finding it hard to purchase a gravity feed cup gun to spray conversion varnish on some furniture I build for myself when all I ever used to finish with is air assisted airless systems. Can you get a high build look? Are there limits to big sizes of furniture with high detail that would be out of the question to use a cup gun? Would a compliant be better than HVLP for spraying solvent based clears? I know the AAA's are really nice but I would like to hear from those who have experience with spraying with cup guns.
Forum Responses
(Finishing Forum)
From contributor N:
There are lots of good guns out there but be prepared to pay $200-$700 for a good (or very good) one. I use a Binks M1G with the 93P aircap and a 1.4 nozzle for CV and it sprays CV coat for coat with my AAA with a 411. It's slower but three coats look identical. I've sprayed some big pieces with one but it really shines using it on that one small piece of furniture, tabletop or two doors and a piece of scribe that you forgot when you were spraying with the pump. I can cook up as little as a 1/2 pint of CV so little to no waste for those last minute small or forgotten pieces. Spraying overhead horizontal pieces can be a problem, a problem that can be solved using one of the many disposable cup systems out there. HVLP or compliant makes little difference (I have a compliant Devilbiss that I use for WB). Most HVLP guns need more volume (CFM) than their counter part compliant guns.
If you don't have experience with a pneumatic gun expect there to be a learning curve. Finding that sweet spot of air pressure and material flow (your compressor must be able to deliver the CFM that the gun requires too) can be elusive in the beginning and of course keeping the gun clean is necessary for it to work perfectly. When you do get it dialed in the quality of finish that can be achieved with one is second to none.
To me it just comes down to personal preference and the fact is, a good finisher should be able to lay down a beautiful finish with any type of gun if he knows how to adjust him material, equipment and spraying technique. I have a number of guns but if I could choose only one it would be my trusty old Devilbiss JGA 510 with a 1.8 fluid tip and #30 air cap. I like a big fluid tip because I have always held the belief that it's easier to turn down a gun that sprays wet than to turn up a gun that sprays light. I know it may not have the best transfer efficiency but it lays down a nice wet coat with great adjustability. From dyes to CV and 2K Urethanes I have not found many materials that I can't spray with this gun.
For smaller pieces like furniture, etc. I will use the turbine or cup guns. The turbine combined with an Accuspray 10 GP gives me results that are every bit as good as the AAA. I would use that as a primary gun in a second if I was spraying less than a quart of product at a time. The drawback comes from having to stop and refill the cup during the job while with the AAA you just drop the pickup tube in and spray five gallons without having to stop. The gravity guns run off the compressor also serve a purpose such as for small runs like when we have multiple vanities in a house that are all different colors where we can set up multiple PPS equipped guns and not have to constantly change over. That takes a decent compressor to run. If I had to choose one single thing to spray with I would probably take the turbine and the Model 10 gun. That gives the absolute best combination of finish quality, portability and performance. Obviously everyone is different and so are the needs.
I myself use two SATA's ($420 each) with 1.4 tips, one for clear one for pigments. I also have my pig-gun aka a Devilbiss FLG-3 ($225) which is set-up with a 1.8 tip for prime-time. The SATA's are nice and light for prolonged spraying - their finish is superior to the Devilbiss. I also have an old Binks #7 cup gun for those days when I know I won't be able to get to the gym (any old-time finisher would understand that statement.) All guns are gravity-fed and set-up with 3M PPS necks for that system. With the PPS, I use the 6oz. and 22oz. cups. The 6 oz is used for touch-ups and color samples.
And finally, I just bought a Devilbiss FLG-4 on line for my apprentice to learn on. That gun came in at $275, but comes with a 1.3, 1.5, 1.8 and a 2.2 tip, so that will cover just about any product you can think of spraying.
