There are many reasons for preferring air tools over their cordless rivals. They’re smaller and lighter, they deliver a constant level of power, and there’s no need to recharge or swap out batteries. However, you do need a compressed air supply and hose connecting it to the tool.
In an industrial facility with a compressed air network, adding one more air-powered tool is unlikely to overload the system. For a smaller business though, or for a contractor who travels to job sites, it’s important to pick a compressor with sufficient capacity to power the tool or tools that will be used. Here we’ll explore the factors to consider when choosing a compressor to use with an industrial finish nailer.
Know Your Nailers
Nailers drive nails into wood. Think of them as a powered hammer that dramatically boosts productivity compared to driving nails home by hand.
Common applications include roofing, framing, assembling cabinetry and fitting trim. The main factors distinguishing these are the size of the nail head and the gauge of the nail. Cabinet assembly and trim installation is usually done with a finish nailer. These are designed to drive 16 and 18 gauge nails.
Finish nailers can be either compressed air or battery powered. Battery-powered nailers are more portable by virtue of having no cord or hose, but that’s about the end of their advantages. Negatives include increased size, more weight, (an air-powered tool for 16 ga nails weighs around 4 lbs while one with a battery will be over), and power output that drops off as the charge runs out.
Compressor Air Requirements
Specifications for air-powered nailers detail the cubic feet per minute (CFM) and pressures (PSI) needed. Minimum pressure is at least 70 psi while 90 is a more useful target level. CFM is a measure of the volume of air consumed, which translates roughly to tool power: a bigger, more powerful nailer, such as one used for framing, will need more CFM.
Typically, a finish nailer used with 16ga nails requires around 4.5 cfm (but check the specifications for the tool you are using.)
Understand Compressor Function
A compressor is a type of pump for air. You might think of it as a powered version of the pump used to inflate bicycle tires. What’s important to realize though is that it doesn’t push air directly into the hose. Instead, it’s job is to maintain the pressure within a storage tank or receiver. The hose feeding the nailer is connected to this tank via a pressure regulator.
The nailer consumes air from the tank as needed. When the pressure in the tank drops below a minimum value the compressor runs to put air back in.
Portable compressors, the kind you’re most likely to use with a finish nailer, come in four styles:
- Hotdog or pontoon – the tank is shaped like a small gas cylinder and holds 2 – 3 gallons of air.
- Pancake – the compressor is mounted on a circular, flat-bottomed tank that holds 4 – 6 gallons.
- Twin-stacked – this has two cylinders and holds 4 – 6 gallons total
- Wheelbarrow – this refers to the compressor being mounted on a wheeled frame for portability. These are bigger machines that may have 8 – 12 gallons of tank storage.
A word of caution regarding tank sizes: don’t try converting between gallons and cubic feet. This is because the amount of air in a cubic foot depends on the pressure at which it’s held.
If the tank is small, the nailer will quickly pull the pressure down below the level needed to activate the compressor. Conversely, with a larger capacity tank the compressor will run less frequently.
Recharge time – the time the compressor needs to run to replenish the tank – is directly related to compressor power, usually expressed in hp. The more powerful the motor driving a compressor, the faster it can put back in the air consumed by the nailer. A higher horsepower compressor can also store air at higher pressure in the tank.
Compressor Selection Criteria
The main issue is the CFM required by the nailer. The 4.5cfm required by a typical industrial finish nailer is only the starting point for choosing your compressor.
First, it’s prudent to select a compressor with spare capacity. A good target is 50% extra, which suggests that a 4.5cfm nailer needs a compressor capable of delivering at least 6 and preferably 7cfm. Go too far over though, and you’re paying for capacity you don’t need.
Two other points to consider are:
- How much will the nailer actually run during the course of a day? (The duty cycle).
- Will other tools be powered from the same supply?
Duty cycle determines tank size and compressor horsepower. If a nailer will be used almost continuously throughout the day, look for a big tank and plenty of horsepower. A 6 gallon tank pancake-style compressor will be about the minimum, and you may be better off with a large twin stack or possibly even a wheelbarrow-style unit.
If you want to run multiple tools off a single compressor, you will need more flow. However, unless all the tools will be in operation 100% of the time, you don’t need to total the individual flow rates and add 50%. This is because they are unlikely to be drawing from the tank simultaneously. Instead, just totaling the flow rates required should be more than sufficient.
Get a Compressor That’s the Right Size
A compressor that’s too small will leave you waiting for the tank to refill. One that’s too big will keep your tool running, but you will have paid more than you needed. Right-size the compressor to use with an industrial finish nail gun by looking at the specs to see how many cfm the tool requires. This is your starting point, but remember to add in some spare capacity, and think whether you may want to run multiple tools from one compressor.