Rolair

Rolair air compressors are contractor machines built around a cast-iron, oil-lubricated pump, the kind that runs all day on a framing or trim job and keeps running for years. The electric hand carry and wheeled units are the ones most crews buy first: small enough to haul up a flight of stairs or roll off a trailer, with enough air for a nailer crew working off house power.

Rolair builds its compressors in Hustisford, Wisconsin. Engineer Bob Laumer founded the company in 1959, the Kelley family, whose shop built its compressor saddles, bought the company, and the Kelleys have run it for three generations. It made its name in residential construction with portable compressors, and its focus today is air compressors and pneumatic accessories.

The VT hand carries: VT20TB and VT20ST

Both VT models run a 2 HP, 115-volt motor turning a single-stage pump with a cast-iron cylinder at 1,700 RPM, and both deliver 4.2 CFM at 90 PSI. The slow pump speed is the point. A pump loafing along at 1,700 RPM runs cooler and quieter than a screaming oil-less unit, and at 74 dBA a crew can talk over it inside a house. The pump is splash-lubricated, rides on ball bearings and uses stainless-steel reed valves, the build a crew wants on a machine it runs every working day.

The VT20TB is the wheelbarrow version, with a 3.2-gallon tank, heavy-duty flat-free tires and a built-in toolbox. Its motor is rated S-1 for continuous duty with a low amp draw, so it can run on a long day without cooking itself or tripping a temporary pole. The VT20ST carries a 4.2-gallon low-profile stack tank, a 12.5-amp motor and weighs about 68 pounds shipped, so it’s the one to carry up the stairs for trim, cabinets, siding and punch-list work.

The 9-gallon wheeled twins

When a framing or roofing crew runs more than one gun, step up to the 9-gallon wheeled twin-tank units. The 1.5 HP model is rated at 6.9 CFM and comes in a dual-voltage version, and the 2 HP model delivers 8.8 CFM at 90 PSI, close to double the air of a VT hand carry. Both use a belt-driven, single-stage pump with cast-iron twin cylinders, a multi-finned flywheel and an air-cooled aftercooler that knocks heat out of the air before it hits the tank, so less water ends up in your hoses and guns.

Voltage is where the twins differ. The standard 1.5 HP twin is a 115-volt machine built to run on a 20-amp breaker, the dual-voltage (DV) version of it can be wired for 115 or 230 volts, and the 2 HP twin runs on either. On a jobsite with a 230-volt outlet at the panel, a 230-volt machine starts easier and pulls half the amps. The totally enclosed steel belt guard on the 2 HP model keeps fingers and gloves out of the belt on a crowded deck.

Sizing to the crew

Between the hand carries and the twins sits the 10-gallon horizontal-tank unit with a tank gauge: more reserve air than a VT for a one-gun crew that fires steadily, without a twin’s weight. It runs the same oil-lubricated pump design as the rest of the electric line, and the bigger tank means the pump cycles less often on a trim or siding job where one gun fires steady all day.

Size the compressor by how many guns fire at once and what kind they are. A trim carpenter with a finish nailer and a brad nailer is well served by either VT. A framer on one gun at a steady pace can work off a VT, but a roofing or framing crew running two or more guns wants a 9-gallon twin, because the extra CFM is what keeps the tank ahead of the triggers instead of the guns waiting on the pump.

The mistake that shows up most with electric units is a long, light extension cord: voltage drops over the run, the motor labors, and the breaker trips. Plug in with a short, heavy cord and put the distance in the air hose instead.

Cold starts and daily care

Every oil-lubricated Rolair ships with a synthetic-blend oil that holds a consistent viscosity year-round. Standard compressor oil thickens in the cold and makes the pump harder to turn over, and that is the difference on a Montana framing job in January, when the compressor has sat on the trailer all night and has to start at first light. Top off with a synthetic blend and check the level every morning. Drain the tank at the end of every day, because condensation left in the bottom rusts it from the inside out.

The VT hand carries and 9-gallon twins at a glance

Model	Motor	Tank	CFM at 90 PSI	Build
VT20TB	2 HP, 115 V, continuous duty	3.2 gal	4.2	Wheelbarrow, flat-free tires, toolbox
VT20ST	2 HP, 115 V, 12.5 A	4.2 gal stack tank	4.2	Hand carry, 68 lb shipped
9-gallon twin, 1.5 HP	115 V, runs on a 20 A breaker	9 gal twin tank	6.9	Belt drive, cast-iron twin cylinders
9-gallon twin, 1.5 HP DV	115 or 230 V, dual-voltage	9 gal twin tank	6.9	Belt drive, cast-iron twin cylinders
9-gallon twin, 2 HP	115 or 230 V	9 gal twin tank	8.8	Belt drive, cast-iron twin cylinders, steel belt guard

Frequently Asked Questions

Are Rolair compressors any good?

The pump is where you can see it. Even the small VT hand carries use a cast-iron cylinder, ball bearings, stainless reed valves and splash lubrication at 1,700 RPM, the build you’d expect on a much bigger machine, and the VT20TB’s motor is rated for continuous duty. Other manufacturers also build Rolair’s complete compressor assemblies and bare pumps into their own equipment.

Where are Rolair compressors made?

In Hustisford, Wisconsin, where the company set up in the village’s industrial park and where the plant has grown to nearly eight times its original size. The same family has run it for three generations.

What oil should I use in a Rolair air compressor?

Stick with a synthetic-blend compressor oil like the one Rolair fills its pumps with at the factory, and skip the detergent motor oil from the truck, which is made for an engine crankcase, not a compressor pump. The VT pumps hold 10 ounces and the 9-gallon twins hold 34 ounces, so a quart covers a full change on a VT with room to top off.

Why does my Rolair electric compressor keep tripping the breaker?

An electric compressor starting against a full tank pulls hard, and a shared circuit or a long, thin cord makes it worse. Give the compressor a circuit of its own instead of sharing it with a saw on the same temporary pole, use a short heavy cord, and on the 2 HP twin or the dual-voltage 1.5 HP twin run it on 230 volts wherever the site has it.

Does Rolair make a gas compressor?

Yes, gas belt-drive units for sites with no power at all, and they make up most of what Rolair sells. For a crew working off house power or a temporary pole, the electric VT hand carries and 9-gallon twins on this page are the ones to buy: no fuel, no exhaust in the garage, and they start in the cold with a switch.

Can you get replacement parts for a Rolair compressor?

Yes. Rolair supports its compressors with a wide range of repair parts and accessories, so belts, filters, valves and fittings for the pump are available. Write down the model and serial number from the compressor’s tag first, because that’s how the right part gets matched to your unit.