A spray gun is an essential tool in the world of polyurethane and varnish application since it allows you to apply the material smoothly and evenly over a large surface area in less time than by using brushes or rollers. But which spray gun should you get?
There are lots of options out there, each with its own unique characteristics that make it better suited to some tasks than others. Here are some things to keep in mind as you choose the best spray gun for polyurethane application.
Best spray gun for polyurethane – Buying guide
So for someone that understands the value of a spray gun in finishing how do you choose one?
- First decide on your source of air: Compressor vs Turbine
- Second, choose a configuration for your spray gun: Gravity, siphon, or pressure fed.
- Third, decide on quality: How deep in your pockets you’re willing to dig
- Finally, decide on the brand: competition keep manufacturers on the cutting edge of technology
Source of air
Your first choice is between a gun that runs off a compressor and one that runs off a turbine. It’s important to emphasize that almost all compressor-supplied spray guns sold today produce the same soft spray, called HVLP. or High-Volume Low-Pressure, as do turbine-supplied guns, Practically speaking, there is only HVLP anymore)
Choose a compressed-air spray gun if you already have a compressor that produces at least 7 or 8 CFM (about 2 horsepower) and has a 20-gallon or larger air-storage tank, or if you need a compressor to operate other tools such as a sander or nail gun.
Choose a turbine spray gun if you need portability or if you’re short on space; turbines are small, Turbine spray guns are usually sold together with the turbine, but you can mix and match if you like because the
connections are standard.
A compressor gives you more control over the air to the gun than a turbine does because you can increase the pressure as much as you want (though going over 10 pounds per square inch at the air cap breaks the definition of HVLP and can be legal in some areas But the air produced by a turbine is dry so
there’s no need to insert moisture-removing filters as there is with a compressor.
Spray guns that operate off each air source are available in three configurations;
All three work well but for slightly different situations,
The siphon-feed configuration has a material cup attached under the spray gun. In the old high-pressure guns, a vacuum draws the fluid up through a tube into the air stream where it is atomized.
But high-volume air in HVLP guns doesn’t create enough suction o do this. So the cup has to be pressurized through a tube running from the gun body to the cup. Some of the air is thus siphoned off from the airflow, which can cause poorer atomization and increased orange peel if the air supply isnt
Though most under-the-gun cups are now pressurized, manufacturers still call them siphon-feed.
Gravity-feed guns, with the cup on top of the gun, don’t need to be pressurized.
The fluid flows into the atomizing air stream by gravity alone. No pressure is needed, though some turbine-supplied guns do pressurize this cup to increase the fluid flow.
Having the cup on top of the gun has the advantage of eliminating the possibility of dragging the cup across a horizontal surface if you aren’t careful.
But you can fit a siphon-feed spray gun into an interior cabinet space much easier than you can a gravity-feed gun, and a siphon-feed gun is more versatile because it can be converted to pressure-feed simply
by replacing the cup with a connecting hose to a separate pressurized pot.
The pressure-feed system, with its separate pot that is pressurized by compressed air, is usually limited to production situations where a high volume of work is being finished,
But not having a cup attached below or above the gun frees the gun to get into small spaces and even to be used upside-down, You may find that having these options is worth the extra effort involved in cleaning the pot and connecting the hose.
Most turbine guns are siphon-feed. Gravity-feed guns seem to be more popular with finishers using compressors, probably because this is the configuration used by auto-body finishers. This is the bigger market, so most available compressor guns are gravity fed.
Quality/ Price points
If you’re looking to buy a spray gun specifically for polyurethane, know that it’s important to pick one with a high level of quality.
Quality in spray guns translates primarily to better atomization minimizing orange peel, tighter control of the spray pattern, more accurately machined parts, and better quality metal for components enhancing damage resistance.
However, if you are on a budget then there are some good options available that won’t break your bank account.
Once you’ve decided on quality, you need to choose a brand. There’s not a big difference among brands
in any given price range. So the key factor you’re looking for after you’ve decided how much you want to spend is service. You will usually get faster service from a local distributor than from mail orders.
For compressed-air spray guns, I recommend you shop at a local auto-body supply store. In my experience, non-chain stores are more knowledgeable about pray guns than the national auto-parts chains.
Find out from the clerks which brands the local auto-body guys use and choose from among those brands. The clerks will understand the subtleties of these brands and the store will most likely stock parts.
These stores also carry very inexpensive “knock-off” spray guns, or you could buy one at a home center or Harbor Freight. These guns produce fairly good results, but the orange peel they produce is more evident
because the atomization isn’t as good.
For turbine-supplied spray guns, you should also look for a distributor in your area. Paint stores that target professional painters sometimes carry turbines and guns.
Otherwise, check web sites of the brands, you’re considering and choose from among
those that give the most helpful information and easy parts ordering, Many woodworking
suppliers carry one or more of these bands.
Best Gravity spray gun for polyurethane – Our top picks
We did some digging for the best available spray gun that works well with poly and other oil finishes. After analyzing about 15 brands we have a tight list of the 5 best spray guns for polyurethane spraying.
Our overall best gun is the Austro Pneumatic Spray gun. This is the best entry-level spray gun at just under $50. However, you will need a source of air. If you do not have and you are an absolute beginner to spray systems then our runners-up Semi-Pro 2 by Fuji is the best go.
This spray system is the best bang for buck spray system. Fuji M-Model spray guns offer professional features. What we loved about the semi-pro 2 model is that it doesn’t ‘spill’ — spraying only when the trigger is pulled. The handles are insulated. And the rear-mounted fan control knob makes it possible to change the spray pattern size from small circular to wide and all between.
Such features are usually reserved for crazy expensive professional spray guns like the Graco Ultra Max II or DeVilbiss T8300 HVLP spray gun. If you are looking for something slightly different, don’t worry! We have four other excellent options for you to choose from.
The Best Spray Guns for Polyurethane
- Austro Pneumatic Spray gun – best entry-level
- Semi-Pro 2 -Best Spray system
- TCP Professional 9 Piece Gun – Best set
- HomeRight Finish max– best DIY
- DEWALT HVLP Spray Gun -Best gravity-fed gun
- FlexSpray Paint Sprayer – Best airless for beginners
Other useful accessories
- Water-Air Separator – For oil-based poly finishes
- Paint Filter Cone – Filtering the finish
- Spray Gun Maintainance kit – For easy gun cleaning and maintenance
- Chemical respirator and other PPE – Safety first!
The best spray guns for polyurethane – Review
The Austro Pneumatic spray gun is the best entry-level spray gun, perfect for those who need a durable, reliable tool for use with polyurethane and other thick finishes. The operation of the gun is as of any spray gun with three main settings you can fine-tune: The fan pattern, the flow, and input air pressure.
The most important thing that will set brushwork and spraying apart is atomization. Atomization happens when the air disperses the liquid poly into a thin mist. This helps the poly to dry remarkably fast. With this gun, you get a fully adjustable wide fan pattern control.
This gun is also easy to clean a feature that has become so important recently. A lot of manufacturers make guns that are hard to take apart and clean. if you can’t clean a gun it will just stop working after some time especially if it is subjected to adhesive-type of mediums like polyurethane.
With this excellent spray gun, you will be able to complete tasks more quickly without sacrificing your quality of work – always meeting your customer’s expectations. It also requires less physical effort than painting by hand, because the weight of the trigger can be adjusted according to user preference.
The price point is also very attractive for someone that doesn’t intend to break the bank just to apply some poly on a deck or fence.
This gun will need an air source but if you do not have an air source like a compressor and want a whole package that can get you started on spraying finish our next spray system is second to none!
The Fuji Spray Semi-PRO 2 HVLP Spray System is the best setup that gets you everything you need in one purchase. The Semi-pro 2 comes with the Turbo 2 turbine and 25ft hose, as well as the M-Model spray gun which is ready to use right out of the box.
The Semi-pro 2 features significant upgrades to both nozzle technology and atomization technology in order to provide a more efficient and accurate way of spraying poly onto your project.
It’s a 2 stage setup meaning you get more air power from the double fan enhancing the atomization of your finish.
Although poly does not require much in terms of spray gun sophistication, the semi-pro 2 still makes it to our list for the sheer reason of versatility.
Down the line, you may want to finish your project with paint or some more complex finish. You will appreciate having all the power and control offered by the Semi-pro 2.
another great thing about this spray system is that it comes with a long hose of around 25ft giving you the flexibility of having the turbine away from your project. Sometimes if the turbine is in your way you may find it difficult to move in a standard pattern.
hesitation when applying poly with spray is the last thing you want. Any time you hesitate there is paint built on that spot which really ruins the finish.
The TCP 9-piece is our favorite gun sold as a set. It comes with 3 guns small, medium, and large.
The advantage of having this set is you can switch between different coatings quickly without needing to clean a whole bunch of tools.
the biggest gun comes with a pin and nozzle size of 1.8mm just like the Austro pneumatic. A bigger nozzle allows you to use poly without thinning to light a mixture.
The smallest gun is what is called the ‘touch up’ gun. Basically, the gun has a tiny nozzle of 1mm making it ideal for retouching or detailing.
The kit also includes an air filter. Air filters are very important when using oil finishes. If you plan to use oil-based polyurethane make sure that you have an air filter as it filters the moisture from the air that may ruin your finish.
It also comes with a pressure regulator for more air control though it’s not necessary but you may want to use it and see how it works for you.
This kit is ideal for someone that would like a little versatility at a reasonable price.
The HomeRight Finish Max is our best DIYers choice because of its portability. It’s a one-stage with a build motor and fan. Making it a little weak for thick mediums but it still manages to push the poly however it’s not recommended for professional-grade work or large projects.
For a person working on personal home projects with no compressor or turbine and who doesn’t want to invest in expensive spray gear, this is the perfect and cheapest option available.
This sprayer is also relatively light allowing you to work on a project with a steady hand for a prolonged period.
If you are a beginner in wood finishing and want to learn the art of wood finishing the HomeRight Finish Max is a good place to start.
If you have been using the No-name-HPLV guns you may have started to notice that the quality can at times be questionable. Not always of cause, but it tends to be more work to produce decent work with a low quality no name gun.
Upgrading to this gun will make you appreciate all the finessing on this gun. While there are way better professional guns out there this gun still does some nice work making it a favorite for many hobbyists.
With this spray gun, you can get a more even application of your poly. The weight balance of the gun is also worth commenting it is a full stainless steel gun.
For all those that would like to step up a notch in the spraying department, this is a reasonable and inexpensive upgrade.
Choosing the best spray gun for polyurethane a summary
When choosing the best spray gun for polyurethane remember that air source, price point, configuration, quality and brand are the most important criteria. Starting small is not a problem but it will tend to be more work.
if you want a nice near-professional poly finish then you might want to invest in something a little bit expensive but if you plan to earn from woodworking then investment will serve you well.