New HVLP gun

[jonnyfontaine]

Way back in auto body school we had this great SATA gun, oh my god i fell in love with that gun, but that's WAY out of my price range $100-$300. I good friend recommend Warwick, and his opinion carries a lot of weight as winner of best paint in several major car show all over california. I personally never heard of them, but i've been out of the Custom car game for over 10 years. I'm not talking about a turbine unit. But a gun you hook up to a compressor. I prefer gravity feed, great since almost all guns are made that way now. But i'm not to familiar with the LVLP guns, if anyone loves those could you please fill me in, just in case anyone reading this isn't getting the acronyms (HVLP- high velocity low pressure, LVLP- low velocity low pressure) again since i know so little about LVLP guns i'm not sure which is most efficient but since i don't spray all that often, getting the best possible finish is most important. While I have fairly good gun control I would still like a spray gun that I can rely on and is user friendly, easy to adjust, and won't break the back. Thank you so much. Oh yeah, 90% of the finish is nitrocellulose lacquer. Possibly, but maybe not water born finish as well. thanks so much. as i always so the best forum ever. thanks

 

[chris_goris]

Its actually high volume, low pressure. Some people try to replicate this with standard compressors but it cant truly be done as efficiently as a dedicated turbine compressor and hose (complete HVLP system)

 

[Phil S]

I have used a Warwick gun but for a very short time. It appeared to be a mid-quality gun with a good trigger response. It only comes with one tip - extras are $50 each

In my shop I use a Devilbiss Finish line 4 FLG-671. Great gun, comes with 1.3, 1.5 and 1.8 tips. Plus I have the Dekup disposable cup system which is a real time saver. This is a HVLP system that will only run on my large compressor as it consumes 13 cfm @ 23 psi

I also have a Sprayit SP-33000 which also comes with multiple tips and does a respectable job if you have the spray pattern down around 6 or 7 inches, fine for woodworking, not so much for automotive. This is a LVLP gun and will run on my small portable compressor. It only takes 3.7 cfm @ 30 psi

 

[jonnyfontaine]

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

Its actually high volume, low pressure. Some people try to replicate this with standard compressors but it cant truly be done as efficiently as a dedicated turbine compressor and hose (complete HVLP system)

 

[ehpoole]

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.

 

[Jeremy Scuteri]

I have heard before that the temperature of the compressed air can be a differentiating difference between compressors and lower cost turbine systems. I don't know how true this actually is.

 

[ehpoole]

I have heard before that the temperature of the compressed air can be a differentiating difference between compressors and lower cost turbine systems. I don't know how true this actually is.

Actually, turbines are often much hotter (the more stages the hotter still) than an air compressor as the air compressor typically has a lot more surface area to dissipate heat before the spray gun whereas a turbine has but a very short path direct to the spray gun. However, if you have a tremendous amount of moisture in your air then hotter air can actually be a positive, though hot air can also cause some finishes to dry too quickly such that they may not flow and level properly, but you have to run an air compressor pretty hard in near 100% humidity to have a real problem provided you have a proper moisture trap ahead of the spray gun and a properly sized air compressor and tank (but spray finishing in such high humidity conditions can have its own finish issues regardless of which type spray system one uses).

Ideally one would generally spray with room temperature to warm air that is dry and contaminant free (which is generally achievable with an air compressor with proper moisture filters installed inline). However, in practice each system has its pluses and minuses under certain conditions so I would tend to consider it more of a wash overall and a lot comes down to personal preference. For me, personally, I prefer the versatility of a large air compressor with one, or more, HVLP spray guns (with multiple tip sizes to choose from) -- and other assorted pneumatic tools to round out the air compressor -- unless portability is a primary concern in which case I feel that the turbine systems then win out so long as one buys a sufficiently powerful turbine system to meet all their finishing needs to begin with. That said, if someone else feels the exact opposite then I really would not argue, either, as both can be fine solutions and if properly outfitted one will not go wrong either way.

With a proper setup, or at least something in the general ball park, it is ultimately more about technique and building familiarity with your equipment and finishes through practice that is really the biggest determining factor in a good spray finish job. The equipment matters only up to a point.

 

[chris_goris]

I agree with all of what Ethan has said here and I will add this, you get what you pay for. Hands down, buy a cheap gun, youre gonna get a cheap finish.

 

[Robb Parker]

I read all the time about inexpensive spray guns applying a good (satisfactory) finish result. Although I'm not saying it cannot be done, I am saying the learning curve will be great without very good equipment. All the trigger pulling in the world will not make up for a gun that will not properly atomize a product at the correct viscosity. If you have ever tried to spray the inside of a cabinet in the three corner surfaces, you know what I mean. There are many factors involved in satisfactory spraying, quality of incoming air, viscosity and quality of material, atomization of that material, transfer rate and application technique. Some of these can be controlled by the end user, others only by the equipment utilized. After I have invested hundreds of hours in the wood shop on a project, the last thing I'm going to do is gamble on my equipment's ability to apply the desired finish in the spray room.

After spraying for almost 40 years, I have a Sata Jet 3000 HVLP with a 1.9 tip and their disposable cup system spraying solvent based materials. Air rate at tip is 12 lbs adjustable at the gun. Transfer rate about 85-90%. This is the best gun set up I have ever used (and I've spent and used a lot), quality of atomization and transfer rate are outstanding. With the cost of nitro and two part finishes, transfer rate is important. You can find these guns for $350-550.00 range today. If we are finishing a whole house of cabinets, a AAA is the way we go. Here we shoot a CA Technologies AAA with the Bobcat gun. Kinda like spraying cabinets with a fire hose. Fast and transfer rate is 95-98%. Air at tip 7-9 lbs. Just my recommendations.

We can spend thousands on cutting and processing equipment, but if you can see your way to spending hundreds on your spray equipment, it will be money well spent.

 

[Gofor]

I spent a lot of years spraying paint but my experience with the various models and makes of equipment is dated. (I still have a couple old operational Binks Model .7s, lol, that do a great job with nitrocellulose lacquer but transfer efficiency is in the toilet). Binks Mach 1 is the latest version HVLP that I have experience with. That said, some things do not change.

IMHO, the best set-up is a gun with a remote pressurized cup. Separate regulators on cup and at the gun. (in-line regulators are too cheap not to use for fine adjustment of fluid flow and atomizing air). You can turn the gun upside down or sideways, and the spray pattern and fluid delivery remains the same.

For a compressor, cast-iron oil sump piston type are quiet and will last many many years if maintained. For small items like guitars, etc, a compressor with close volume capacity to the guns rating can be enhanced by the use of a larger storage tank. You should be able to find a good HVLP gun that will spray lacquer at 8cfm or less.

Water borne finishes are a whole different ball game. Water is a large molecule that due to its weight and size, requires much more air to atomize into a uniform spray. The only equipment I have used that would do this well was an airless system. It can be done somewhat well with a pressurized fluid system (pressure pot or cup), less so with gravity feed, and almost impossible with a siphon cup.

JMTCW

Go

 

[ehpoole]

IMHO, the best set-up is a gun with a remote pressurized cup. Separate regulators on cup and at the gun. (in-line regulators are too cheap not to use for fine adjustment of fluid flow and atomizing air). You can turn the gun upside down or sideways, and the spray pattern and fluid delivery remains the same.

Such is certainly superior for large jobs where a lot of material is being sprayed each day or in very tight confines (though a smaller gravity fed touch up spray gun can also be used in confined spaces), but they are seldom practical for the more typical workshop projects due to the complexity of the paint path and the degree to which things need to be broken down and cleaned after each use or at the end of a day spent spraying coats. By comparison, the popular gravity fed spray gun is trivial to clean in just a couple minutes, or less, with a very modest amount of solvent (a couple ounces), with only occasional need to actually break all the parts down for a thorough scrubbing (and even that break down is trivial due to the straightforward paint path). But if one is regularly spray finishing by the gallons per day then a remote pot is highly desirable despite the added time spent cleaning everything at the end of the day as the time savings from the larger pot coupled with the convenience of a lighter spray gun will offset the added time required to properly clean and break down the unit when finished.

 

[Gofor]

I was not talking gallons pre day, I was talking amounts as little as a measuring cup of coating. A one cup pressurized cup, or a 2 qt pressure pot with 4' hoses also can be cleaned with ounces of fluid. The second rinse solvent is recovered and use for the initial cleaning for the next session. Typical clean-up time is 5 minutes or less.

Your statements are right on if thinking about a 2 gallon or larger pressure pot.

Gravity feed is a good system for small work, and has advantages over a siphon cup. It also has limitations that a pressure system does not. Just another method offered for the OP's consideration.

Upon doing a search, I see that there are now "gravity feed" guns that have a cap with a pressure hose attached. May be the best of both worlds for some applications. As for having the coating container on top, underneath, or remote, that becomes a matter of personal preference on how you like the gun to balance.

Go