What Is a Random Orbital Sander?

Here’s a full guide on random orbital sanders — how they work, what to look for, how to use them well, and some strong product options.

What Is a Random Orbital Sander?

A random orbital sander (sometimes called a “dual-action sander”) is a handheld power tool that sands surfaces by combining two motions simultaneously:

1. Rotation — the sanding pad spins in a circular path
2. Orbital / Eccentric Movement — the pad also moves in a small orbit (off-centre), producing random swirls

Because the motion is random (i.e. no fixed circular path), each grit of abrasive doesn’t trace the exact same path twice. This significantly reduces swirl marks and visible sanding grooves.

In short: it’s more forgiving than a purely orbital sander and gives smoother finishes, while still removing material efficiently.

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What It’s Used For & Advantages

Common Uses

• Wood Smoothing & Finishing — prepare surfaces before staining or varnishing
• Paint / Finish Removal — strip old finishes (with coarser grits)
• Surface Leveling — flatten small imperfections, low spots
• Between-Coats Sanding — light sanding between coats of paint or clear finishes
• Metal & Composite Finishing — light deburring, polishing (with very fine grit / pads)

Key Benefits

• Minimised Swirl Marks — less visible patterning on finished surfaces
• Versatility — works well across grain direction
• Dust Collection — many models integrate dust ports / vac connection
• Variable Control — many include variable speed for different materials
• Ease of Use — generally smooth, intuitive operation for amateurs and pros alike

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What to Look for in a Good Random Orbital Sander

Here are the primary specs and features to compare when selecting one:

Feature	Why It Matters	What’s Good / Typical Ranges
Orbit Size (mm) / Eccentricity	Larger orbits remove material faster but may increase risk of gouging. Smaller orbits give finer finishes.	2.5–5 mm typical ranges
Pad / Disc Diameter	Determines how much area is covered per pass.	125 mm / 150 mm are common sizes
Power / Motor Strength	More power helps maintain speed under load	At least 200–300 W for corded; for cordless, strong brushless motors
Speed Range / Variable Speed	Helps you match material (soft wood, hardwood, finish)	E.g. 4,000 – 12,000+ OPM or similar
Dust Extraction / Port	Keeps workspace clean, extends sandpaper life	Good if it supports vac hookup or has built-in filters
Ergonomics / Vibration	Lower vibration and comfortable grip reduce fatigue	Look for reduced m/s² vibration ratings, rubber overmold grips
Durability & Build Quality	Rugged design, sealed internals, good bearings, reliable switching
Accessories / Backing Pads	Extra pads, varying densities, or replacement parts matter
Corded vs Cordless	Corded gives continuous power; cordless gives portability (if battery strong)

Also, matching sandpaper quality and the right grit progression is crucial to get good results.

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Tips & Best Practices for Use

• Start with coarser grit and then step through finer grits — e.g. 80 → 120 → 180 → 220, etc.
• Keep the sander flat; don’t tilt or “ride an edge” or you risk gouging.
• Don’t apply too much force — let the tool do the work. Excess force can cause swirl marks or bog down the motor.
• Move the sander constantly — keep it in motion so no spot is overworked.
• Use the dust port / vacuum hookup to capture fine dust (improves visibility, air quality, and pad life).
• Change sanding discs when worn — a dull disc causes heat buildup and poor performance.
• Sand “on, off” technique — start the sander when it’s in contact, stop after clearing the surface to avoid edging marks.
• Overlap passes — use a systematic pattern so you remove prior grit marks evenly.
• Maintain & clean — brush dust off pads, check backing pad condition, and keep the tool in good shape.
• For finish work, use lighter grit and lower speed to reduce scratches.

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Product Examples & Recommendations

Here are several well-regarded random orbital sander models (corded or cordless) to consider. Use their specs and features to compare what fits your needs: