• March 2025 Turning Challenge: Identical Bowls or Plates! (click here for details)
  • Congratulations to Joseph Bernard for "Working Spider" being selected as Turning of the Week for March 3 2025 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Sanding lines.

L

Lancer Gooding

Joined
Mar 31, 2024
Messages
6
Likes
5
Location
Jay, OK
When I'm done sanding I have a peice that has no visable sanding lines. but if you turn it in the light there are faint lines on the piece.i make bowls.
I use 80 grit then 120. 150. 220 320 400 .
Can anyone tell me what I am doing wrong?
Thanks.
Lancer
 
Hello Lancer. I don't think it's an issue of grit progression, but beyond that it could be any number of things. I'm gonna stab in the dark here:

-Clogged abrasive, full of sanding dust, need fresh paper. (Avoid X-weight cloth backed papers, way too stiff. I like J-weight cloth papers over paper-backed papers.)
-Pushing too hard on the paper.
-Not taking enough time at each grit.
-Taking too much time at each grit(?).
-The species of wood and their unique characteristics (alternating hard/soft grain and growth rings)
-Other will probably add to the list, but it's about the variables.

But if I'm going to look at any of your, or my, notes first, it's the 80 grit paper tracks, maybe the 120, not being fully erased by the next grit before moving on. What to do?

Use that side light to your advantage, and in those lower grits, carefully analyze the surface before moving to the next grit. Always have fresh clean paper. A rubber sandpaper cleaner can help, but grab clean sandpaper. Maybe toss some 100 grit in between the 80 and 120.

(Edit- after you are done with a grit, clean the surface well to make sure a piece of heavier grit didn't break off the paper and is stuck to the wood. It will be pulled along by the finer paper and mess up your work.)

Here's the challenging one- we don't know each other, so parden my assumption, but how are your cutting techniques before starting the sanding? Are the tools able to give you a fine surface before you sand, or are most times and most woods requiring starting at 80 grit? This one is huge. If your tools are kept proper sharp, and if your cutting techniques are very gentle and deliberate in the final/finishing cuts, you'll find your surface can start the sanding process at 150/180 rather than the course 80 grit. Carefully watch your final cutting surface (use that side lighting) so you don't have to depend on course grits.

I think it will be a combination of sharp tools, cutting technique, and sanding process noting those points above. I've watched lots of Tomislav Tomasic videos on Youtube (a protoge of Richard Raffan) and he does a great job in many of his more instructional videos of showing fine tool control and abrasive use. Take a peek at each of their videos, see if you can find that one, or maybe two vital tips that will get you over the hump. Good luck!
 
Last edited:
This is something I have been working on quite a bit. It is especially an issue on the inside of bowls. I seem to be able to get the outside turned now without that problem, though it was an issue when I first started. First, I worked harder at getting the tool marks out with the gouge and scraper. The better the surface before sanding, the less sanding is needed. One of the things that helped me, was to go back to an earlier grit when I saw that the finer grit wasn't really getting the job done even if it was only one little spot. I also stop the lathe and do spot sanding with the grain, particularly on the end grain sections. Sometimes the sanding circles aren't visible until you put some kind of finish on them. A light coat of sanding sealer with show the sanding rings and also stiffen the fibers so you can sand those sections better. Hope this helps.
 
I use both an electric drill and a pneumatic RO sander. I only use the drill on the lowest grit. It is very aggressive and will leave a lot of scratches. But it works great to get the tough stuff out. Then I switch to the RO at the same grit. That will take away the scratches left by the drill. From there on I use the RO exclusively.

The drill is so aggressive I often go up one grit. For example, if I'm starting to sand at 120, I'll put 180 on the drill, get the tough spots sanded, and then back to 120 and the RO.
 
IS this with just paper, or are you power sanding? I will probably stir up some people, but don't see the point of sanding with 150 after 120 because it's such a small jump. I was told less than double for the next grit is adequate. You should be able to sand away the lines of the previous grit, and shouldn't move on until you do. Use your good lighting in between, not just as a final inspection. Changing direction of sanding can help a lot too.

If you can improve your cuts, 80 grit will become something you rarely ever use again.
 
Last edited:
I struggled mightily with this issue early in my turning journey; sometimes still do. My problem came down to bearing down WAY too hard with 80-grit (and sometimes even 60!) trying to get the perfect curve with the sandpaper because my shear-scraping skills were not developed enough yet to get it off the tool. Plus I was using paper to erase tear-out, tool marks and bottom humps inside until I learned better tool control and sharpening. If you start that low, it takes a lot of sanding at 120, 150 and 180 to remove those low-grit scratches before moving up. (And I'm a believer in lightly hand-sanding at 150 to get rid of any pesky lines before moving up to 180; that's just what works for me). I'm pretty sure an ROS is in my future, but now I'm mostly using your basic Harbor Freight 50-dollar angle drill with 2-inch pads (sometimes 3 for bigger stuff). And you really can't have too much light on a piece you're sanding and checking in between grits; a strong light at a raking angle to show the shadows is a big help. But as I am often sanding in the late afternoon after turning in the morning, I find that if I can take a piece off the lathe and look at it in late afternoon sunlight (even if you have to take the chuck with it), it shows scratches that even the best artificial light doesn't reveal.

I can't speak for others, but for me 180-grit is my "Do not pass go!" grit like in Monopoly. In other words, don't even think about going higher after 180 until you have inspected every surface at different angles under strong light because you're just making more work for yourself later if you do.

Though I developed a lot of bad habits early on because I started turning during the pandemic isolation of '20-21, the biggest epiphany I had that changed the way I sanded completely for the better was learning to STOP bearing down so hard (often with worn-out paper because I'm cheap!) and think of each sanding grit as just a finer cutting/finishing tool. Thus a light touch is needed, just like those ultra-light finishing passes with a shear-scraper, NRS, etc. And once I started getting smoother finishing cuts by slowing down my feed rate and getting better finishing passes on curves with my body movements instead of my hands, I was/am often able to start sanding somewhere between 120/150/180, occasionally even higher if I hold my mouth right. And that really is key; getting 80-grit scratches out of the super-hard woods I favor like pear, curupau, dogwood, etc. is not impossible, but it is close enough to it that I don't ever want to have to try it again!

I hope this helps. Sanding well is an art all unto itself, and it helps mightily if you don't have to do so much of it! And yes, there are some great videos online like Lyle's above, but I have had a good bit of in-person, extended turning instruction by some world-class turners, and sanding is often addressed late in a course or class and given short shrift due to time constraints, everyone is tired and starting to get in clean-up mode, etc.
 
Sanding is something I do way to much of :) Consequently my sanding skills have improved over the years.

If you don't have to start at 80 you'll be much better off, but I've gone back and forth on the 'trying to start at 220' thing. We had a professional turner at our club a couple months ago that spent time talking about sharpening etc, and then commented even with perfect sharpening and cutting techniques he *always* starts sanding at 120. I have found if I start too high I spend a lot of time and then just back down a grit anyway.

To your original question, wood species might come into play too. If I'm turning walnut I can see scratches left from 800grit (800 RO I can't), but if I'm turning oak I'm pretty sure the scratches are invisible beyond ~220 (although I go through 320 RO anyway).

My technique in general is mostly powered. On bowls I'll usually start with 120-180 on a drill with a fairly hard backing, power sanding with the lathe on ~200rpm. I'll admit that if I have bad tearout or want to do some shaping I will start at 80, but I go through a lot less 80grit than I did years ago. Next I move up a level (120/150/180/220/320/400/600/800 on very hard tight grained woods, skipping at least one of the alternate grits on softer or open grained woods). Still with a fairly hard backing I'll power sand and then stop the lathe and sand using the drill any specific areas that need it with that second grit. After that I switch to a soft/flexible backed disk on an RO sander and sand 320/400 on most, sometimes stopping at 320 for oak etc, other times progressing through 800 for walnut as mentioned.

If you cut cleanly you'll find that the first sanding level will take a minute or two, and the second similar with the lathe off inspection and spot sanding, after that you can sand at each level for less than a minute on a 6-8in bowl.

In general I find that an RO sanding with the lathe spinning at ~200 is at least as clean as sanding without RO at the grit higher.

BTW - make sure you have good dust collection and I highly recommend wearing a respirator. I purchased a Peke CleanAir a few years ago that I love, and it gets me in the good habit of wearing a face shield as well. Your lungs are worth it, you won't get another set if you damage them with wood dust
 
Last edited:
This is all great advice and great reminders. My question to y'all who use an RO sander is, which what where? What RO have you found that is small enough to get inside a bowl? I would love to find one with like a 2" pad all though that might be unrealistic. Also if it's air powered then how big a compressor or how much CFM do you need to run it? I know a 5" RO requires a LOT but maybe if they are smaller they require less.
 
Raif Harik said:
This is all great advice and great reminders. My question to y'all who use an RO sander is, which what where? What RO have you found that is small enough to get inside a bowl? I would love to find one with like a 2" pad all though that might be unrealistic. Also if it's air powered then how big a compressor or how much CFM do you need to run it? I know a 5" RO requires a LOT but maybe if they are smaller they require less.
Click to expand...
The RO sanders that Woodturners Wonders sell come with 2" and 3" pads they both use 3 cfm @ 90psi. I have a 3 hp compressor that makes 12 cfm @ 90 psi and it cycles on & off as it should. When you purchase a RO sander match it to your compressor output. I looked at a lot of sanders and most of them require 8 to 10 cfm which would make my compressor run all the time.
 
Raif Harik said:
This is all great advice and great reminders. My question to y'all who use an RO sander is, which what where? What RO have you found that is small enough to get inside a bowl? I would love to find one with like a 2" pad all though that might be unrealistic. Also if it's air powered then how big a compressor or how much CFM do you need to run it? I know a 5" RO requires a LOT but maybe if they are smaller they require less.
Click to expand...
I’ve used the small RO sander from Woodturners Wonders for a year or two and love it, other than I’ve had issues and had to tear it down a couple times. Because of this I also recently purchased the Grex pistol shaped RO but haven’t used it much after getting the other one fixed.

I use 2” and 3” discs, the larger ones most of the time. Regarding air supply, I have a 30gal 5.5scfm compressor from Lowe’s that works great.
 
Lancer Gooding said:
When I'm done sanding I have a peice that has no visable sanding lines. but if you turn it in the light there are faint lines on the piece.i make bowls.
I use 80 grit then 120. 150. 220 320 400 .
Can anyone tell me what I am doing wrong?
Thanks.
Lancer
Click to expand...
Can you describe the lines? If you are hand sanding with the lathe turning, and the lines are circular around the bowl, perhaps slowing the lathe and moving the sandpaper left and right will help. If you are power sanding and the lines are small circles you might experiment with less pressure on the sandpaper and more time with each grit.
 
I bought a compact pistol-grip pneumatic random orbit sander on Amazon for about $40. It included an assortment of disks of different grits in 1, 2, and 3 inch sizes.
 
So, I am no expert, however I have had my struggles with sanding as well.

Two things:

1. Is it essential that you start at 80 grit? Or even 120?
2. Are you only sanding with the lathe on, leaving scratches around the piece as a result?

If your tooling is good enough, especially if you are doing things like proper sheer scraping on the outside, and cleanup on the inside with a good quality and properly sharpened scraper, then starting at 80 grit could BE THE problem. If you end up with a nice clean wood surface, 80 grit is like dragging a newborn baby across a gravel street by horse.... In otherwords, and atrocity to the wood! ;) If you are tooling to a good finish, then maybe start at a higher grit. Even 120 might still be too coarse, so you might try 220. If you are not tooling your wood to a quality surface, and are instead using sandpaper as a means to say clean up tearout...then maybe consider honing your skill with tools to produce a cleaner surface to start with. Sheer scraping on the outside can do a nice job to clean up quite a bit of tearout on the outside of a bowl, while a good quality scraper can do wonders on the inside. If you generally get a LOT of tearout, I'd look to sharpening your tools more often and better. This was the greatest realization I had when I first started turning...just how important REALLY sharp tools are. Especially with woods that are prone to tearout, a super sharp tool will still cut the fibers and leave minimal if any tearout.

Another thought is if you are only ever sanding lathe-on. This forces the grit to dig in around the piece, which is rarely really with the grain. It may be with the grain at only moments, then cross-grain everywhere else. I always hand-sand my pieces for the last couple of grits at the very least. If you sand only with the lathe on, then your always going to have scratches. TECHNICALLY speaking, you always have scratches no matter what, really. Even at very high grits...its just that the scratches get small enough to become invisible to the naked eye. Up to 400 grit, they can definitely still be visible to the naked eye...and there is potentially another issue with grits that high that I'll get into in a moment. Getting your scratches to disappear, has a lot to do with grain alignment. Sand across the grain, you rip and shred those fibers. Sand with the grain, and you will kind of hide the scratches within the fibers. It can depend on the wood, exactly which aspect of the grain you sand with. There are actually various characteristics in each wood, and some are better at hiding scratches than others. Sometimes, it may just be as simple as sanding the bowl from center to edge along the long grain (which can't be done with the lathe on at all.) Other times, you may need to sand with the aspect of the grain that kind of curves along the bowl from end grain to end grain, which can be trickier, but if you can do it, then you CAN hide the sanding scratches within the grain (well, technically, I guess the proper term for those bands would really be the tree rings.) It really depends on the nature of the wood, though, and what hides scratches best.

On grits...I used to sand to very high grit, as I often used friction polishes for my finish, and t hey seem to work better when you sand the wood VERY smooth. Something I learned somewhere along the way, though, is that beyond a certain point, you are less sanding and more burnishing, with higher grits. Those grits can start around 400 or 600, and the issue gets more pronounced the finer you go. What I noticed in my own work, was that even though the wood surface was becoming VERY smooth, even shiny, despite the grit being very fine, when it left scratches (say counter to some aspect of the grain, which is worse around knots, figure, and other grain oddities), they stood out that much better against the otherwise polished, burnished and shiny smooth other wood. So it may be worth, taking your sanding up to only 320 grit. Then, if you need to sand and polish it even finer, add a sanding sealer, then sand that smooth with a higher grit (600, maybe even 800), maybe put on a couple of coats of the sanding sealer and sand it all super smooth, then put your final finish on. The sanding sealer will help a lot with higher grit sanding (although its definitely not immune to this problem I just described!)
 
I bought one of these to try and I've been very happy with it. I have a lot of hand and wrist problems and this has not only worked well, it's been very comfortable.

https://www.amazon.com/dp/B07SVR6WV9?psc=1&ref=ppx_pop_dt_b_product_details

I have the small one from WtW, but didn't like the big paddle on the back. The index finger trigger works better for me. They all seem to require a fair amount of air, but I put an adjustable valve in line with it to get finer control and reduce the maximum speed. The pneumatic RO sanders all seem to go way faster than I'd want to use on wood.
 
Lancer Gooding said:
When I'm done sanding I have a peice that has no visable sanding lines. but if you turn it in the light there are faint lines on the piece.i make bowls.
I use 80 grit then 120. 150. 220 320 400 .
Can anyone tell me what I am doing wrong?
Thanks.
Lancer
Click to expand...

Late to this party.

Are you seeing circular scratches? It's hard to know without watching you work, but I suspect you're doing what others have mentioned - circular scratches come from sanding with the lathe running. Coarse paper like 80 grit makes this far worse. First thing to do is work on tool control so 80 grit is never needed. This is easier said than done - the best thing I know is, if possible, find a mentor whose work you admire.

My suggestion:
  • Never sand by holding sandpaper against the spinning wood. I do most sanding by hand, with the lathe off.
  • Follow sanding with any grit by sanding with the same grit at some angle to the last sanding direction. My thinking is if I can't remove cross scratches with the same grit, I certainly won't be able to remove them easily with the next finer grit.
  • Make sure sandpaper is high quality and sharp. Big mistake is sanding with worn paper - throw it away before it's worn out. I keep rolls 1" and 2" wide at the lathe and tear off small fresh pieces often. My favorite paper is Klingspor Gold.
  • Use good lighting while working. I use bright small dia lights on flexible necks positioned to glance the light at a low angle to the wood. This helps see scratches that need to be fixed.
  • One little trick after sanding: apply naphtha to the wood with a piece of paper towel. It dries quickly and leaves no residue. As it evaporates, any remaining evil scratch will become visible for a few seconds since the scratch will hold the liquid a little longer than the smooth surface.
I also NEVER use rotating sanding disks on a drill/angle drill. I don't like the clouds of dust and don't like what it does to the wood at times, especially to detail and crisp edges. I do have a nice Milwaukee close quarters drill but I use it only for [gasp] drilling in tight places.

So all that said, here's how I work to get smooth surfaces on face work like bowls and platters:
#1: Start with very sharp tools and use the best tool control I can manage.
#2: Remove gouge marks and surface irregularities with a negative rake scraper, or if appropriate, I may shear scrape with the wing of a gouge or another tool. For most surfaces I prefer a NRS of my own design (subtly different than others I've seen). I use other custom NRS for smoothing other places such as the detail inside the foot.
IMG_7511_ce.jpg IMG_7515_ce.jpg
(Sorry to bore those who've see these photos before.)

#3: After the NRS, smooth with hand scrapers, almost always with the piece off the lathe with the chuck mounted on a carving and finishing stand. Makes it far easier to work and to see.

Some hand scraping in progress. I grind rectangular cabinet scrapers to various curves, sharpen, and burnish a burr. They can work wonders - take out tool marks, surface irregularities like ripples, annoying central defects (depressions and humps), and minor tearout.
scraper-shavings-IMG_7864.jpg

#4: After the hand scraping, sand by hand, all off the lathe. I back up the strip of sandpaper with a soft "Magic Rub" eraser.

For me the key is using hand scrapers before any sanding. When I show this technique in demos I take this piece - the only sandpaper that has touched it was 600 grit:

penta_platter_cedar_IMG_7434.jpg

Since I started working on face turnings like this, getting surfaces that satisfied me became a lot easier. I've been on my hand scraper soapbox for years now. I usually can start with 400 grit or occasionally 320, rarely coarser. Note that I don't get in a hurry - I'd be a horrible production turner.

I save the 80 grit for cleaning brake drums.

I use modified methods for thin spindles, lidded boxes, goblets, ornaments and finials, small things like finger tops.

JKJ
 
There is obviously a lot of experienced advice from many points of view here.

I'm assuming the OP is talking about concentric scratches left from the last sandpaper grit used and not scratches left by a previous grit.

It's already been mentioned in the thread more than once, and I'll concur that the way to stop leaving this type of scratches, is to keep the paper moving back and forth as the bowl spins on the lathe......eliminate the tendency to hold the paper in one spot. This helps to keep the direction of the paper to be more of a "cross hatch" method, which is very beneficial to the purpose.

=o=
 
@Lyle Jamieson.....

I see you are using Merit Powerlock discs. I am using them as well. Problem is that they have been discontinued from my sources. I have purchased some from usatco.com, but they don't supply them in all the grits and types and quantities. Are there other sources that you are aware of? Thanks...

=o=
 
Ric Williams said:
I bought one of these to try and I've been very happy with it. I have a lot of hand and wrist problems and this has not only worked well, it's been very comfortable.

https://www.amazon.com/dp/B07SVR6WV9?psc=1&ref=ppx_pop_dt_b_product_details

I have the small one from WtW, but didn't like the big paddle on the back. The index finger trigger works better for me. They all seem to require a fair amount of air, but I put an adjustable valve in line with it to get finer control and reduce the maximum speed. The pneumatic RO sanders all seem to go way faster than I'd want to use on wood.
Click to expand...
This sander says it runs on 2.7 cfm @90. I've got a 6 gallon ridgid pancake that says it does 2.6 @90. As you mention they do run wicked fast, so if I turn down the pressure, would that make it run better? Do you think this sander would work with my little pancake?
Thanks
 
Depending on the wood, I start sanding anywhere from 80 to 120. If I start at 80, I go to 100, 120, 150, 180, 220, 320, and 400. Perhaps the most difficult thing to learn as you sand is to make sure you get all the sanding scratches out from the previous grit before you step up again. I do over sand some times. The sanding drills do better at slower speeds, or maybe cut more effectively. I spend far more time with the lower grits than I do with the higher grits. I use natural spectrum lights since that is what our eyes evolved to see best in. One turner commented, "Never take a finished piece from the shop into the house on a sunny day. Sunlight causes scratches!" I also have prescription glasses. I used to use the old magnifiers from the big box stores, but they just were not good enough. Being able to see is huge. I do wipe my bowls out with my hands. I never blow more dust into the air. By wiping my bowls off with my hands, that will push the finer dust into the coarser scratches. The best abrasives I have found are the blue discs from Vince at WoodNwonders. They cut longer and faster than any others I have used. Also, use a firm pad for coarser grits, up to 180. At 220 through 400, I switch to a medium pad. The firm pad Vince has with the 1/4 round profile on the edge is best for the insides of bowls. I did use the Milwaukee/Sioux drills for years. Milwaukee no longer makes their angle drills.

robo hippy
 
I'm sorry to be hijacking the thread to talk about ROS'. So one final statement. I found two ROS' that operate on 2.7 and 2.2 CFM ( one is the one Ric mentioned ). They are not cheap ( 85 and 122 ). The 122 @ 2.2 has a 105 angle which seems great, but the reviews say that if a fly lands on it it will stop. I am going to purchase both and see which one is best/tolerable. Then I will write a review in a new thread.
Thanks

p.s.
I'm wondering if getting one that requires 3 or 4 CFM but applying a regulator to it to reduce air flow might be the better option. They all run way too fast. Crap. I guess I'll get one of those too. I'm going to return the losers of course.
 
Raif Harik said:
This sander says it runs on 2.7 cfm @90. I've got a 6 gallon ridgid pancake that says it does 2.6 @90. As you mention they do run wicked fast, so if I turn down the pressure, would that make it run better? Do you think this sander would work with my little pancake?
Thanks
Click to expand...
Yes, it would work, but not that well and could very well burn itself up trying. Putting a valve or regulator inline would help some but not enough. It reduces the speed but doesn't affect the cfm requirement enough to get away with using a too small compressor. You'd be forcing it to run pretty much constantly to keep up (100% duty cycle) and I guarantee they're not made for that. Most consumer grade compressors are rated for 50% duty cycle, but a lot of times the cfm numbers are at 100%. I'm on my third compressor now, not because I wore them out or made them run too much, but because, despite the cfm ratings given matching up with the tool(s) cfm ratings, it forced the compressor to run much more than they were meant to. I would recommend getting a compressor with twice the cfm rating you think you need if you intend to keep it for as long as possible. FWIW, my current and previous compressors are Quincy single stage compressors and I really like them. I only sold the first Quincy after I bought a bigger one to better handle the work load I was giving it. I made the mistake of ignoring my usual "Buy Once, Cry Once" philosophy and I bought the cheaper, lower capacity compressor and quickly discovered my mistake. You've been warned! ;)
 
You must log in or register to reply here.
Back
Top