What is the Difference Between a Single Stage and Two Stage Compressor?

single stage vs. two stage air compressor

Some air compressors come in two types: single and two stage. When it comes to buying a single stage or dual stage air compressor, the first question that prospective buyers often ask is “What are the differences between the two?”

Single Stage vs. Two Stage Air Compressor

The main difference between single and two stage compressors is the number of times that air gets compressed between the inlet valve and the tool nozzle. In a single stage compressor, the air is compressed one time; in a two stage compressor, the air is compressed twice for double the pressure.

Single stage compressors are also known as piston compressors. The process that takes place within a single stage compressor goes as follows:

  • Air is sucked into a cylinder
  • The trapped air is compressed in a single stroke with a piston at roughly 120 psi
  • The compressed air is moved onward to a storage tank

In the storage take, the compressed air serves as energy for the assortment of tools that a single stage compressor is built to accommodate.

The process within a two stage compressor — alternately referred to as a dual stage compressor — is similar to that of a single stage, but with one variation: the compressed air isn’t sent to a storage tank; it’s instead sent to a smaller piston for a second stroke, this time at roughly 175 psi. From there, the double–pressurized air is cooled and delivered to a storage tank, where it serves as energy for vast arsenals of high–powered equipment.

People who are new to air compressors will often confuse the number of cylinders for the number of stages in an air compressor, when in fact both single and two stage compressors use two cylinders, because it’s easier to balance air that way. The difference between the two stage air compressor vs. single stage in this regard is that, in the latter, both cylinders are the same size. On the other hand, in two stage compressors, the second piston is shorter than the first, and the two are linked by a cooling tube, which brings the temperature of the air down before the second round of compression.

Uses of Single Stage Versus Dual Stage Air Compressors

Dual stage air compressors produce higher air power, which makes them the better option for large–scale operations and continuous applications. However, two stage compressors also cost more, which makes them better suited for factories and workshops than private use. For the independent craftsperson, a single stage compressor will power a variety of handheld pneumatic tools that don’t exceed 100 psi. At auto shops, pressing plants and other settings in which complex arsenals of air–powered machinery are utilized, the higher capacity dual–stage units are the more preferable option.

Woodworking

Out of all the activities that a person could do in their garage or backyard, few are as tool–intensive as woodworking. From cutting and sawing to sanding, drilling and nailing, there’s a vital tool being used along every step of the way, regardless of whether you’re making furniture, canoes or living–room fixtures. Some of the tools used in these steps can be quite intensive in that they require a lot of physical exertion. As such, woodworking involves a certain degree of physical stamina, as well as hand–eye coordination.

However, for all the tools that require such exertion, there’s a pneumatic equivalent that will bear the brunt of the task in question. Imagine being able to cut each board and drill each hole evenly and easily in a matter of seconds; it’s all possible with air–powered saws and drills. All you have to do is hold the tool in place and the air power does the rest — no strained wrists, no overworked shoulders or elbows. Best of all, each application is accomplished so fast that there’s little time to slip or ruin a project.

With a single stage air compressor, you could power a vast array of woodworking tools that would make it possible to achieve in minutes what would otherwise take hours with old–fashioned hand tools. The kinds of tasks that you could accomplish with a single stage compressor include the following:

single stage versus dual stage air compressor

Sawing: Once a woodworking project has been conceived, the first major step involves trimming the boards and cutting out the shapes and panels for use. Historically, wood cutting was a dangerous task, best left to the strong and skilled. But now it’s far easier with a pneumatic speed saw, which can slice through wood in just a fraction of the time it would take to manually run carbide blades from one board side to another. Air–powered speed saws can be fitted with blades of various lengths for different board thicknesses.

Nailing: Hammering things together can be one of the most awkward and risky parts of any woodworking project. Awkward because a slip of the hand could bend the nail or send it in crooked. Risky because you could also miss the target and hammer your thumb, the board or even the underlying surface. Worst of all, nails often fail to go in all the way, either due to a hard, impenetrable depth or because the nail wasn’t straight in the first place. The solution to these problems is an air–powered nailer, which sends nails in straight and even while penetrating thicknesses without a fuss. Best of all, it will do all of this in seconds, up and down along a given board.

Drilling: Due to the fact that hole–formation relies heavily on hand–eye coordination, the act of operating a drill can be just as awkward as hammering a nail. Any wrist or elbow slip could send a drill in crooked or cause the hole to spread too wide for the allotted nuts and bolts. A drill is also a very powerful device, which can be problematic when you fire off target and send a line of holes off balance. Such risks are greatly reduced with the use of an air–powered drill, which can drill holes through 2x4s faster, and with greater accuracy.

Sanding: After the project is assembled, the raw edges and rough surfaces need to be smoothed out and polished. Sanding makes the difference between raw wood and panel material, but it usually takes machinery to achieve such transformation. Sure, sandpaper has been around for ages, but the grains of sand usually leave marks or streaks in whichever direction the hand swings. This isn’t appropriate for any piece of wood that a person might use for a chair, cabinet or picture frame. These are the reasons why woodworking requires an orbital pneumatic sander, which moves around in multiple directions for a smooth, streak–less finish on all types of wood surfaces.

Metal Work

If woodworking is a trade that’s greatly facilitated by the use of air compressors, work involving metal is virtually impossible without them. As the world’s strongest material, metal is a lot harder to cut, drill, mold and join together. While it’s still possible, though not exactly preferable, to power woodworking tools with your own physical strength, the same cannot be said for metal work. Simply put, metal crafts require electric or air–powered tools that go above and beyond mere human capabilities.

The following tasks can be performed on metal within seconds with a single–stage compressor and the appropriate pneumatic tools.

Shearing: As conventional wisdom holds, metal alloys must be molded a certain way in order for the finished product to come in a particular shape. What most people don’t know is the power of pneumatic metal–cutting tools. With an air–powered shear, metal workers can cut through sheets of metal in a similar manner to cutting cardboard with a rotary cutter.

Grinding: Everyone knows what to do when trimming is needed on wooden sheets and boards, but what about when the same thing is needed along metal tubes, pipes and bars? For the material that’s supposedly impervious, pneumatic grinders work wonders. Whether you need to cut a long brass bar in half or trim an inch off the edge of an aluminum pipe, it can all be done in under a minute with an air–powered grinder. When attached to a single stage air compressor, a grinding tool can be especially useful when that small but critical metal piece is just a few millimeters too wide to fit with a corresponding space.

Riveting: Welding is not the only way to join metal pieces together. In the fabrication of metal drawers or cabinets, plates of metal are joined in a similar manner to panels of wood in oak or mahogany furniture, only the fasteners are different. When metal sheets are combined to build sheds and other structures, rivets are typically the fastener of choice. Using a pneumatic riveter, you can join two metal panels tight along the seams in seconds. The pneumatic riveter sends pin–like fasteners through pre–made metal holes for a tight, secure fit.

Ratcheting: There are certain metal fasteners that need to come undone; trouble is, time acts as a natural welder. When a nut has been screwed as tight as can be, with the purpose of never being unscrewed, you could have your work cut out for you with a regular wrench. For problems like these, there’s the air–powered ratchet, which will break long–stuck nuts loose from bolts and allow you to disassemble items, regardless of how far back a given item might date. Within seconds, a ratchet can separate what would otherwise end up joined for all time in a landfill.

All of these wood and metal applications can be performed independently with tools that operate at 90 psi or under with a single stage compressor.

two stage air compressor vs. single stage

Auto Assembly and Maintenance

With so many heavy–duty applications performed in the process of vehicle construction, pneumatic tools and machines save untold sums of energy at assembly plants. Unlike personal crafts and small–scale operations, however, assembly plants need more than merely 100 psi to perform the vehicle construction and maintenance.

At plants and repair shops alike, two–stage compressors make it possible to pneumatically drive the following applications:

single stage vs. two stage air compressor

Lifting: The assembly of vehicles requires tons of parts lifting, from the frame and shell to the engine and passenger compartment. At the early stage of vehicle construction, there are parts that need to be mounted onto a conveyor belt for piece–by–piece assembly. After the car is mostly assembled, it needs to be lifted overhead so that finishing touches can be applied. A two or three stage air compressor can be used to power lifting devices with suctions strong enough for heavy loads.

Screwing: From engine parts to hubcaps, there are a lot of parts to be screwed and bolted together production. With air–powered impact wrenches and ratchets, work crews can quickly assemble and disassemble vehicle parts, so that each car can be moved along the conveyer with utmost efficiency.

Greasing: An engine consists of several key parts that are continually in motion during vehicle operation. Most of these moving parts are made of metals that would grind together and wear out from friction if it wasn’t for lubrication. As with most machines — air compressors included — grease is vital to the life of each vehicle. At assembly plants, pneumatic–powered greasers apply lubricants on a variety of car parts, some of which are difficult to reach or too hot to handle.

Painting: In the eyes of the casual observer, paint makes the vehicle. What isn’t commonly understood is the complex process of painting vehicle shells. The shells must be primed and coated in a clean environment, free of moisture or oil in both the pneumatic and atmospheric air. Two stage compressors can be used to power paint sprayers, which provide streak–free, blotch–free coats for an overall smoothness that could never be achieved with spray cans or rollers.

Two and three stage compressors are also ideal for powering pneumatic tools and machinery along the production lines at furniture factories and food–packing plants.

Learn More About Single and Two Stage Air Compressors

two stage air compressor vs. single stage

Regardless of the size or scope of a given operation, air–powered tools are essential to the productivity of craftspeople and work crews alike. As an independent woodworker or the owner of crafts line. A single stage compressor could help make products faster, better and more efficiently. If you manage a work crew at a large pressing plant, two stage compressors could be used to power the most heavy–duty aspects of your operation.

When it comes to air compressors, Quincy Compressor has long been established as one of the most trusted names in the business. To learn more about our small portable and large stationary units, visit our sales and service page to locate the nearest Quincy service representative.