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SKIL 5” Random Orbital Sander with Cyclonic Dust5 inches7.87 x 4.8 x 5.51 inches3.44 PoundsCheck on Amazon
5-Inch vs 6-Inch Random Orbital Sander for Large Panel Finishing
For large panels, a 6-inch random orbital sander can remove finish faster and cover more surface per pass. A 5-inch sander is usually easier to control, costs less to equip, and handles detail work better. Neither size automatically produces a better finish. The right choice depends on how much material you need to remove, how large the panels are, and how well you can manage dust and pressure.
For most occasional woodworking, cabinet, and furniture projects, a 5-inch random orbital sander is the safer general-purpose purchase. If you regularly finish tabletops, doors, stair parts, or wide plywood panels, a 6-inch random orbital sander can save meaningful time.
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Size and coverage
The sanding pad diameter tells only part of the story, but the difference is useful. A 6-inch pad has about 44 percent more surface area than a 5-inch pad. In theory, that means fewer passes across a panel. In practice, the time savings are commonly closer to 20 to 35 percent because you still need overlapping passes, edge work, abrasive changes, and inspection.
| Factor | 5-inch sander | 6-inch sander |
|---|---|---|
| Typical use | General woodworking, furniture, trim, and detail work | Large panels, tabletops, doors, and production sanding |
| Abrasive cost and availability | Usually cheaper and widely available | Often more expensive; selection can be narrower |
| Control near edges | Easier to control | More likely to tip or overhang |
| Material removal | Good for normal preparation and finish sanding | Faster on broad, flat surfaces |
| Typical pad speed | Often more forgiving in the hands | Can expose defects quickly if used aggressively |
| Best value | One-sander shop and occasional users | Frequent large-panel work |
On a 4-by-8-foot sheet, the 6-inch machine has a practical advantage. It spends less time covering the middle of the panel, where control is easy and there are few obstructions. On a small cabinet door or narrow shelf, the advantage largely disappears. The larger pad may actually slow you down around corners and inside frames.
Finish quality and control
Both sanders use an eccentric, or random-orbit, motion. This reduces visible swirl marks compared with a simple rotary sander, but it does not make careless sanding harmless. The most common failure is putting too much downward pressure on the tool. Pressure slows the pad, reduces the random action, and can leave circular marks or uneven scratch patterns.
A 6-inch sander often feels smoother on a wide panel because its weight is spread over a larger pad. It can also bridge small surface irregularities instead of dropping into them. However, its larger footprint makes it easier to tilt when the pad crosses an edge. A tilted sander can round a panel edge in seconds, especially with 80- or 100-grit abrasive.
Keep the pad flat, let the tool’s weight do the work, and move at roughly 1 to 2 inches per second. Make overlapping passes by about half the pad diameter. On a large panel, mark a loose grid in pencil and sand until the marks disappear. This reveals skipped areas better than judging the surface by feel alone.
Grit sequence and panel preparation
Choose the sander based on the worst job you expect, not just the final finish. For a clean, factory-flat panel, starting at 120 grit may be appropriate. For milling marks, glue squeeze-out, or a small height mismatch, start at 80 or 100 grit and stop as soon as the defect is gone. Spending too long with coarse abrasive creates trenches that later grits must remove.
A practical sequence for many bare-wood panels is 80 or 100 grit, then 120, 150, and 180 grit. Dense woods and stain-grade work may benefit from 220 grit, but sanding beyond 180 can reduce stain absorption and produce a blotchy result on some species. Change abrasive when cutting slows noticeably or when the paper is loaded with finish and dust. A worn disc encourages extra pressure, which causes more problems than it solves.
Before sanding, scrape glue beads and remove raised defects with a sharp hand tool. A random orbital sander is not an efficient substitute for a scraper or block plane. It can level a thin glue smear, but it may also spread the smear across the grain and make it harder to see.
Dust collection and running cost
Large-panel sanding generates a surprising amount of dust. The sander’s small cloth canister is adequate for a short repair, but a vacuum with a fine-dust filter is a better setup for whole panels. Use a hose adapter that does not pull sideways on the tool. Poor hose routing can make a light 5-inch sander feel awkward, while a heavier 6-inch tool becomes tiring faster.
Six-inch discs usually cost more per piece, and you may need to buy them in fewer grit options. Five-inch discs are available almost everywhere, including hardware stores, and are often sold in larger mixed-grit packs. That difference matters if you sand only a few projects each year. For a shop that uses dozens of discs monthly, the larger pad’s time savings can outweigh the abrasive cost.
Use discs with matching dust-hole patterns when possible. Universal perforated discs can work, but poor alignment reduces extraction and loads the abrasive. A loaded disc cuts slowly, runs hotter, and increases the temptation to press down.
Which one should you buy?
Choose a 5-inch sander if you want one tool for furniture, shelves, cabinet parts, and occasional large panels. It is the better choice when edge control, low operating cost, and readily available abrasives matter more than maximum coverage. The cheaper option is completely adequate for a few 2-by-4-foot panels, particularly when the wood is already well milled.
Choose a 6-inch sander if large, flat work is routine and you are comfortable controlling a wider pad. It is especially useful for tabletops, doors, workbenches, and multiple sheets of plywood. A 6-inch machine is not a replacement for a 5-inch tool on narrow parts; if your projects mix both jobs, the practical answer may be owning a 5-inch sander first and adding a 6-inch unit later.
Whichever size you buy, prioritize a comfortable grip, low vibration, variable speed, a reliable pad brake, and effective vacuum extraction. Those features affect the final surface more than a small difference in motor wattage. For finishing large panels, consistent movement and the correct grit sequence beat raw sanding speed.