How frequently do you change ROS sandpaper discs? (and other dumb sanding questions)

[Dan Friedrichs]

I'm finding my sanding skills/results lacking, and wonder if I'm doing something fundamentally wrong.

Some questions:
1) Say you've got a 5 or 6" ROS with excellent dust collection and high-quality paper (Mirka or Festool, etc). Assume you're sanding a large table top (or something where 100% of the sandpaper is contacting the work). How much time do you put on a sanding disc before you consider it "worn out"? (Seems like a new disc quickly loses a bit of sharpness, but beyond that, is it usable for 30 seconds or 30 minutes?)

2) How thoroughly do you vacuum/brush off a surface when switching between grits? Is it: "Not at all - the (Festool) dust extractor gets it all", or a "I spend several minutes with the air compressor blowing every last remnant of the last grit off"?

3) How much time do you spend with each grit? Say you were sanding a completely-flattened coffee table top (~2'x4') through 120, 150, 180, 200.... is that a multi-hour procedure or a ~15 minute procedure?

4) Finally, would you do any hand sanding of a flat surface, or is the ROS the last step? Even using what I think are "best practices", a sideways-aimed flashlight shows sanding scratches that I'm worried will show up after finishing, so I end up using a sanding block to do the final sanding "with the grain". Is that normal/necessary?

[Charlie Jones]

I probably change the ROS paper to often. I would rather waste a little than spend more time sanding. That is my least favorite woodworking task. I start at 80 for most surfaces. I use 80 to get rid of defects then switch to 150 to take out the 80 scratches. Then 220. Sometimes 150 will do.
I brush and vacuum the surface between grits. When I think I may be done, I wipe the surface with mineral spirits. That will tell you if your done or need to go back and sand some more. If I am aiming for A
high gloss finish I may ROS to 220 then block sand with 220. If the finish is oil or matte I may stop at 150.

[Charlie Jones]

Oh, and I use Klingspor disc's.

[Ole Anderson]

I just refinished an old Lane cedar hope chest. All aromatic cedar. I used 80 grit 6" discs on my 6" PC ROS with the dust collection kit. The finish and wood clogged the paper so bad I went through probably 6 discs. And I turned to the belt sander with 80 grit to finally get down to real wood which still clogged the paper with resin. Used two belts. Hit it with 120 then 220 on the ROS. All PC stick on discs. Four layers of satin P&L 38/naptha 50/50 wiped on. Block sanded out the dust nibs with 400 grit on a foam auto style block only after the last coat. Just like my kitchen cabinets, it looks and feels like raw wood, no plastic look built up finish. Smooth as a baby's skin.

Edit: To answer some of your questions, 1. if they are just wearing out (no clogging) I keep using them for probably 15 minutes of sanding, Although I leave my 80 grit on my 6x48 belt sander months until it breaks, by then it feels like there is no grit left. 2. I generally brush between grits and vacuum after the final grit 3. on a 2'x4' oak machine planed surface I would be less than 5 minutes per grit usually using 120 then 220, but then my PC is pretty aggressive, it is actually the 5" sander with a 6" disc. 4. I might go over everything, particularly the corners, with 400 grit folded in half, by hand. I have a roll of 180 and a roll of 400 2.5" sticky back from the auto parts store. Fold it adhesive to adhesive side and you get grit on both sides. Highly recommended for hand or block sanding.

[Matt Day]

1). If I had to guess I’d say 5-10 minutes of continuous sanding. After a few minutes of sanding I check the wear of the sanding disc visually and by feel. I try not to get to the point where it’s a noticeable difference when I put a new disc on.

2). A few brushes stokes or usually a microfiber wipe down.

3). Generally I spend the most time with 80, as I’m removing planer/jointer marks and it takes the longest to get a consistent scratch pattern. Probabaly 5 minutes on a 2x4 top. Then I go to 120 then 180 then 220 or something like that. Time with each is say 3, 3, 2 minutes, respectively.

4) ROS is the last sanding step for me. Hand sanding, especially a panel is easy to get a long straight scratch pattern going. The random pattern is much cleaner. I wipe down with a rag and DNA to clean dust and mimic what it will look like with finish.

[glenn bradley]

I'm a bit of a broken record on this . . . trying to wring more life out of your abrasives is a false economy. When your abrasive stops doing what you expect it to do (that is; what it was doing when you started using it new) then change it. Quality abrasives like Klingspor, Industrial Abrasives and others are a whole different level than anything you find at the Home Center. Once you make the transition you will wonder why you waited so long to get such an increase in performance for such a small cost (different from price) increase.

[johnny means]

I think of a single disc as being good for approximately the surface of a sheet of plywood. I do three passes of each grit after the initial flattening. If a disc is showing wear, it's way past due, abrasives should still look new when discarded.

[roger wiegand]

The fellows at our turning club constantly say "use sandpaper as if someone else is paying for it". That said I probably use mine too long, I'd guess 20-30 min of sanding time. Typically when I change I get the feeling that the new piece is much faster, which probably means the old one was worn. I have typically spent a long time on the first grit (80), getting the entire surface flat and uniform in its scratch pattern. Subsequent grits I do only until the scratches from the previous grit are gone, maybe 20% the time of the first grit. At the end (180 or 220) I dampen the surface to raise grain and make another very quick pass with the final grit. I never skip a grit, that's the quick way to swirl marks visible only after you apply the finish. I do as much as possible through the SuperMax at 80 grit, then RO at 80 to take out the parallel sanding marks from the drum.

Since I finally (after 40 years of woodworking) learned to sharpen and setup my planes I've found that I can plane the surface flat to a near finished surface and start sanding at 150 or 180. Maybe if I can improve my technique I will reach the nirvana of skipping the sander!

[Dan Friedrichs]

When your abrasive stops doing what you expect it to do (that is; what it was doing when you started using it new) then change it.

Oh, I agree, Glenn. But with a Festool "dustless" sander, I'm having a hard time telling when it stops doing what I expect! :)

Seems like a new piece of paper is "really sharp" for about 10 seconds, then feels about the same for....a really long time? I'm usually throwing paper away when I bump the edge of the ROS into something and it tears a piece off, but otherwise, I can't really tell when I should be changing it...

[Matt Day]

With Norton abrasives it's pretty easy to visually tell as the blue wears away. Not sure about Festool.

[Jim Becker]

I change the disc when it's either clogged with something that doesn't clean off or when there's enough noticeable wear to warrant the change. In many cases, they are still usable for hand sanding at that point. I use compressed air to clean most of the time and sometimes try a gum-rubber sandpaper cleaning stick. I do use Festool and the excellent dust collection absolutely helps prolong abrasive disc life, especially because of that center hole.

[Wayne Lomman]

Change the disc based on a combination of how well it is cutting and is it heating the surface. Remember also that the paper should be doing the work. If you are leaning heavily on the machine it is definitely time to change. There is no set time though. This is different for every timber or timber product. Cheers

[Sam Murdoch]

Never thought about "time" as regards to the use of an sanding disc. I too, likely throw them out early - before they are done, but would rather sand effectively than just go through the motion. Still, I would expect to be able to strip the finish off an entire 48" round table top (normal refinish of a dining table) with one grit before tossing and moving on to the next.

For finishes I have found the Mirka Abranet Mesh far exceeds the Festool papers. It goes at least 5 times, possibly more, without clogging. To the point that I now use it nearly exclusively in my Festool ROs. I still like the Brilliant II for wood or between coats of fresh paint, or Granat for coarse sanding but if I have the Mesh on hand I use that first.

[Jim Becker]

Remember also that the paper should be doing the work. If you are leaning heavily on the machine it is ...

...going to toast the pad on the sander prematurely from heat. :) Leaning also slows the sander down. Excellent point, Mr. Lomman!

[Andrew Joiner]

Oh, I agree, Glenn. But with a Festool "dustless" sander, I'm having a hard time telling when it stops doing what I expect! :)


I test with light pencil marks on the wood. The rate they sand off is visible. I'm usually surprised how long disks last.

[Ron Citerone]

I test with light pencil marks on the wood. The rate they sand off is visible. I'm usually surprised how long disks last.

Good idea. I might borrow that one.

[Warren Lake]

From time to time paper may not be consistent. ive returned paper more than once to one of the largest telling them it was crap. Turns out they used new adhesives in the new more chemical friendly world. At the time doing low production work so had a format this disc does this many pieces all of a sudden I was getting half the mileage? thought about it and it was paper from a last order so made a call. Happy at least they admitted an issue then took care of me showering me with new product.

[Mark Bolton]

I'm finding my sanding skills/results lacking, and wonder if I'm doing something fundamentally wrong.

Some questions:
1) Say you've got a 5 or 6" ROS with excellent dust collection and high-quality paper (Mirka or Festool, etc). Assume you're sanding a large table top (or something where 100% of the sandpaper is contacting the work). How much time do you put on a sanding disc before you consider it "worn out"? (Seems like a new disc quickly loses a bit of sharpness, but beyond that, is it usable for 30 seconds or 30 minutes?)

2) How thoroughly do you vacuum/brush off a surface when switching between grits? Is it: "Not at all - the (Festool) dust extractor gets it all", or a "I spend several minutes with the air compressor blowing every last remnant of the last grit off"?

3) How much time do you spend with each grit? Say you were sanding a completely-flattened coffee table top (~2'x4') through 120, 150, 180, 200.... is that a multi-hour procedure or a ~15 minute procedure?

4) Finally, would you do any hand sanding of a flat surface, or is the ROS the last step? Even using what I think are "best practices", a sideways-aimed flashlight shows sanding scratches that I'm worried will show up after finishing, so I end up using a sanding block to do the final sanding "with the grain". Is that normal/necessary?


Its very difficult to quantify a time or a square footage because so much of it is based on what material your sanding and what your starting with. So if your starting with material fresh off the planer, knew knives, clean, was it run through a sander, is it hickory, maple, or pine, and so on.

Our answers would be:
1. We consider paper worn when its no longer cutting well. Your spending a lot more time removing the same defects you were removing quickly.

2. None. We never clean between grits. We run vac's on the sanders and just switch and keep right on going.

3. Again depends on where your starting from. We will sometimes come straight off the planer and hit quickly with 120, just enough to about completely knock down the knife marks from the planer, then jump straight to 180 and get the rest and finish sand. We try to spend as little time as needed on the lower grits to minimize the deep scratches which will force you to step through every grit. We rarely sand to 180 and usually knock off at 150 for stain/clear finish.

4. Other than breaking edges or knocking down machine marks on an eased edge or profile that we cant hit with the RO we never hand or block sand anything. Moldings are all hand sanded.

We use Mirka Ceros', a 6" PC angle grinder style RO, a couple cheap 5" dewalts, and couple cheap 5" bosch RO's. But the Mirka's and the PC do most of the work. Mirka Gold paper (recently stopped using abranet)

For us I really try to tell people not to focus on any one thing specifically. Dont focus on time because you will sand a piece for 2m53s and the next one will need 3m30s. Dont focus on individual spots because you'll never see everything that needs sanded. Rather just pay attention, make mental notes of areas that need attention but realize you have to bring the entire surface down. Very little rocking the sander up on edge and focusing on a "spot". I think of it like mowing the lawn. Your covering the entire surface many many times. Use your peripheral vision (much more sensitive than looking straight at something) to notice defects and pick up on areas that need attention. If your sanding boards or parts. Stack your sanded parts infront of you. This way while your sanding the part your on, your also glancing up at the last part sanded and catching problems early.

All this aside. When your sanding some Hard Maple for stain your going to be doing a LOT more sanding than when your sanding Cherry or Poplar. The harder the material the less chance to skip a grit. We find Red Oak to be a bear to show sanding marks.

I would agree with the others who say dont be a mizer with your paper especially on harder materials. Change out often. Being stingy with your paper kind of works a bit when turning because no matter how fine you go, if your hand sanding with sheets, your always fighting linear scratches around the piece. So using dead paper less of an issue. But a lot of people think their 120 when it becomes dead is as good as 150 and then it turns into 180 and 220. Doesnt work. Fresh sharp paper is the key.

[Philipp Jaindl]

Abrasives arent the most expensive thing in the shop for no reason, buying good quality paper will increase its life quite a bit however as soon as it stops "biting" well its time to change. I agree with the others using worn out paper really isnt worth it.

As for how long with the Grits: untill the scratches from the coarser grits are gone, we only really use 3 Grits 80/100 , 150/180 and 220/320 for Sanding inbetween coats of laquer or the like.
Though if its a surface that wont be seen it doesnt really matter if there are some scratches left.

[John Kee]

Just a little side note when discussing Festool paper, you really should say the type you are using. Rubin was one of first wood only papers until around 2012, was relatively cheap and wore out quickly. Then they came out with Rubin 2 which was noticeably better and Granat which is one of the longest wearing most versatile papers they make. So in a lot of cases you are comparing apples to oranges as far as sanding time and longevity. One of the best papers I've tried is 3M Rubicon line but you never hear much about it mainly because it makes Mirka's expensive Abranet screens look cheap. I never noticed much difference in life between Festool Granat and Mirka Abranet, in my short time using the 3M Rubicon it was easily the long lasting.

[Dan Friedrichs]

Its very difficult to quantify a time or a square footage because so much of it is based on what material your sanding and what your starting with. So if your starting with material fresh off the planer, knew knives, clean, was it run through a sander, is it hickory, maple, or pine, and so on.

Our answers would be:
1. We consider paper worn when its no longer cutting well. Your spending a lot more time removing the same defects you were removing quickly.

2. None. We never clean between grits. We run vac's on the sanders and just switch and keep right on going.

3. Again depends on where your starting from. We will sometimes come straight off the planer and hit quickly with 120, just enough to about completely knock down the knife marks from the planer, then jump straight to 180 and get the rest and finish sand. We try to spend as little time as needed on the lower grits to minimize the deep scratches which will force you to step through every grit. We rarely sand to 180 and usually knock off at 150 for stain/clear finish.

4. Other than breaking edges or knocking down machine marks on an eased edge or profile that we cant hit with the RO we never hand or block sand anything. Moldings are all hand sanded.

We use Mirka Ceros', a 6" PC angle grinder style RO, a couple cheap 5" dewalts, and couple cheap 5" bosch RO's. But the Mirka's and the PC do most of the work. Mirka Gold paper (recently stopped using abranet)

For us I really try to tell people not to focus on any one thing specifically. Dont focus on time because you will sand a piece for 2m53s and the next one will need 3m30s. Dont focus on individual spots because you'll never see everything that needs sanded. Rather just pay attention, make mental notes of areas that need attention but realize you have to bring the entire surface down. Very little rocking the sander up on edge and focusing on a "spot". I think of it like mowing the lawn. Your covering the entire surface many many times. Use your peripheral vision (much more sensitive than looking straight at something) to notice defects and pick up on areas that need attention. If your sanding boards or parts. Stack your sanded parts infront of you. This way while your sanding the part your on, your also glancing up at the last part sanded and catching problems early.

All this aside. When your sanding some Hard Maple for stain your going to be doing a LOT more sanding than when your sanding Cherry or Poplar. The harder the material the less chance to skip a grit. We find Red Oak to be a bear to show sanding marks.

I would agree with the others who say dont be a mizer with your paper especially on harder materials. Change out often. Being stingy with your paper kind of works a bit when turning because no matter how fine you go, if your hand sanding with sheets, your always fighting linear scratches around the piece. So using dead paper less of an issue. But a lot of people think their 120 when it becomes dead is as good as 150 and then it turns into 180 and 220. Doesnt work. Fresh sharp paper is the key.

Mark, just wanted to say a particular thanks for this very nice write-up. You've given me a lot of ideas for how to "suffer less" when sanding.

[Barry Block]

A few things... I am a huge fan of Mirka abranet. I find it last much longer then traditional sand paper which I change often. When using abranet I don't usuallybother to wipe off the wood with a microfiber towel. When using more traditional types I always wipe. One thing you can do is wipe a hand across the sanded piece. If you feel grit/sand then you definitely need to wipe or vacuum as the course aggregate of the lower grit sand paper will leave scratches as you move up threw the grits.

I'm curious as to how many other people do this as no one else has mentioned it. I always wipe my pieces down with DNA when I hit 180 or higher. This raises the grain and helps high light any of the defects that I might have missed when I sanded. Raise the grain with DNA and then nock it down with another light pass of sanding. This way the grain will not raise as much when you hit the piece with finish. This creates a better, cleaner, flatter finish and if your doing a full fill then you will need fewer coats.

[Mark Bolton]

A few things... I am a huge fan of Mirka abranet. I find it last much longer then traditional sand paper which I change often. When using abranet I don't usuallybother to wipe off the wood with a microfiber towel. When using more traditional types I always wipe. One thing you can do is wipe a hand across the sanded piece. If you feel grit/sand then you definitely need to wipe or vacuum as the course aggregate of the lower grit sand paper will leave scratches as you move up threw the grits.

I'm curious as to how many other people do this as no one else has mentioned it. I always wipe my pieces down with DNA when I hit 180 or higher. This raises the grain and helps high light any of the defects that I might have missed when I sanded. Raise the grain with DNA and then nock it down with another light pass of sanding. This way the grain will not raise as much when you hit the piece with the finish. This creates a better, cleaner, flatter finish and if you're doing a full fill then you will need fewer coats.

We grain raise with water because we shoot waterborne and our planer knives are rarely fresh.

We had the opposite experience with abranet and have switched away from it. The only thing we miss is slightly better dust pickup but in addition to through the pad suction a good clean vac (dust deputy) creates a nice bubble around the head of the sander. The cheap dewalts have their own generated vac for pickup so when you plug them into a vac they are utterly dustless.

I try to stay away from solvents if at all possible and have had issue with a rouge water spots here and there on a sheet of ply or passage door so we just grain raise with water on everything. Raises the grain and turns the whole thing into a giant water spot so no surprises when stain goes on.