Five ways to reduce edger swirl
The worst part about running the edger is the circular scratch marks it leaves behind.
Sometimes these scratch marks are difficult to see (especially for a first-time floor refinisher)… until you apply finish, when they stand out like a sore thumb.
If you don’t realize that you have the dreaded edger swirl until after it’s been coated with a layer of finish, it will take an enormous amount of work to make it go away because you have to sand off all the finish first. But there are ways to reduce the visibility of those scratch marks.
Edger swirl is like sunburn; a small amount of prevention helps you avoid a large amount of pain.
Here are our five favorite steps to avoid it in the first place:
1. Don’t skip grits. Ever.
There are plenty of professionals out there who insist that it only takes three sanding grit passes to sand a floor, regardless of sanding grits how damaged and scarred the wood is, but that is just plain foolish, especially if you’re worried about edger swirl.
If you had to start your sanding with 16-grit, you can’t jump to a 36-grit and then to an 80-grit, especially on the edger because you will still be able to see scratch from the coarse cuts.
The grit spectrum available for floor refinishing looks like this:
36-grit (or 40)
60-grit (or 50)
80-grit (or 100)
Regardless of where you start in this spectrum, you must use all the grits that are FINER than your starting point. This way, the edger swirl is gradually but irrevocably eroded away.
The coarser the grit you use, the more difficult it is to remove the scratches it causes. These grit sequences have evolved over decades of trial and error. We know that each grit in this sequence is only capable of sanding out the scratch from the grit that came right before it.
People tell us that they skip grits all the time when they sand furniture. But when you sand furniture you start at 80-grit and move up from there. Your margin of error is much greater when you’re talking about those fancy fine grits; if you’re careful you can indeed remove 80-grit scratch with 200-grit paper.
But the ability to skip grits breaks down when you’re working with the huge granules found on floor sanding paper. And grit scratch that is not removed shows up as edger swirl. So don’t skip grits, and don’t stop before 80-grit.
2. Use a nylon cushioning pad between your edger and the paper.
It softens and limits the down-grinding power of your edger, which limits the depth of scratch it can leave. These nylon pads do compress down as you use them, so replace them when they get too thin.
And always get a fresh pad when you begin you final edger pass (either 80-grit or 100-grit) so that it leaves as little evidence of its own swirl as possible, while still taking out the 60-grit scratch that came before it.
3. Use the B-2 edger.
Choose a 2-speed edger and use the lower speed for your 80-grit (or 100-grit) pass.
The slower speed makes the edger less aggressive, which reduces the visibility of the scratch, but still allows removal of the 60-grit scratch that preceded it.
4. Don’t overuse your paper.
Sandpaper dulls more quickly than you think and dull paper does not remove scratch effectively. Our edger paper will be dull enough to comprise its scratch-removing ability after 20 linear feet of edging (assuming that you are edging about 9” off your wall). A good rule of thumb is to change your edger paper after two walls’ worth of sanding.
Don’t argue with me about how the paper still feels sharp or is still producing dust; these are not reliable indicators of effectiveness! The only way you know if paper is still sharp is how cleanly it erases the visible scratch from the previous edger pass.
This is why edgers have headlights – to help you actually see the scratch you’re trying to erase. But if you can’t trust yourself to discern that, use light pencil lines all along your edger zone; if the pencil lines erase cleanly and easily as you edge, you are still working with sharp paper.
The moment you have to double back to remove a light pencil line, you have proof that your paper is too dull to erase edger swirl. Watch the video below that explains it!
How to tell where to use your edger. Watch Kadee Macey show you a dandy of a tip to let you know exactly where you must run your floor edger. Length: 1:26.
5. Use a flashlight to identify any remaining edger swirl and sand it out by hand before you even think about applying finish.
Even if you follow the first four directions, you are likely to still have some edger swirl. But by this point it should be shallow and easily erased with aggressive hand sanding parallel to the grain. When we’re in the field, we get on our hands and knees and use a folded over 80-grit piece of edger paper to sand over every part of the floor touched by the edger.
Yes, you will be tempted to use a palm sander instead, but resist the temptation.
Palm sanders can over-polish the floor, or at the very least leave a different texture where they were used, which will limit the absorption of your finish in those areas.
So, if you insist on using an orbital sander to remove swirl, you should still hand-sand over the area where you used the orbital. It is almost impossible to over-polish the floor with hand-sanding so your floor will absorb finish much more uniformly.
Pete’s Bonus Tips
Why can’t I use my palm sander to remove edger swirl?
Well, you can remove edger swirl with a palm sander, but it can lead to the uneven, “Appaloosa” effect.
Which is lovely on a horse, but ugly on your floor.
Palm sanders are mechanical and can burnish or over-polish the areas you sand with them. The texture of those burnished areas is smoother and tighter than the areas that were sanded with the drum sander, and this limits the amount of finish those areas can absorb. Areas where the finish has not sunk as deeply into the wood appear lighter, especially next to their drum or edger-sanded neighbors.
A floor that has been randomly corrected with a palm sander can have the aforementioned blotchy, almost "Appaloosa" appearance. Remember that floor finishes need uniformity to look good, and their uniformity is controlled by the underlying consistency of your sanding job.
It is much safer to correct edger swirl by sanding with the grain using a fresh piece of 80-grit sandpaper and your own arm - because your own arm just isn't capable of burnishing the floor.
If you insist on using a palm sander, either use it over the entire floor (not recommended) or hand sand with 80-grit over the areas that you palm sanded.
Get a one-on-one phone consultation with a hardwood flooring expert. For a small fee, we can provide the wisdom and knowledge that you need to complete your hardwood flooring project. When you don’t know what to do next, it’s time to call Pete’s Hardwood Floors Help Hotline.
Buy online, or stop by our cute store in St. Paul, Minnesota.
Pete's sells supplies online across the continental U.S., and rents equipment to Minneapolis/St. Paul DIYers. Our store at 186 Fairview Avenue North in St. Paul, MN is at the corner of Fairview and Selby.
It's just the cutest sander rental shop you'll ever visit. Call us at 651-698-5888.
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Big dogs. Big claws.
Claws are very hard, and don't have to be sharp to dent wood; that's why even well-manicured pups can inflict damage.
The larger the dog, of course, the more weight comes down on those claws, making them not unlike stiletto heels.
Contact Pete's to rent a sander for your pet-damaged floors.