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Discussion Starter · #1 ·
As I've mentioned in prior posts, I'm new to turning. I love turning things, mostly pepper mills and pens so far, but sanding is driving me nuts. I know most people don't enjoy it, but I'm hoping there are some tips that will help me out. My chief problem is that I get a lot of cross grain scratching that's very hard to get out. I'm using the cloth backed rolls that are sold as the woodturners multi-roll sanding kit. I start at 150 and work my way through the grits, but invariably, I get a "rogue" scratch that isn't removed by the next grit. I get that sanding on the lathe is by its nature cross grain sanding, but jeez, there's got to be a better way. Am I sanding a too high or liw of a speed? Please help with some of those sage tips that make me go "oh,,,that's the trick! Thanks.
 

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When you get down to the finer grits, it helps to dampen the wood with water and raise the grain. Then when you go to a finer grit the sanding is more effective. Just let the water dry before sanding.

It's good you are using the cloth backed paper. I'm sure you have found out the paper can go from room temperature to third degree burn in a blink of an eye with paper back paper.
 

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Discussion Starter · #3 ·
"I'm sure you have found out the paper can go from room temperature to third degree burn in a blink of an eye with paper back paper."

:) Yup, discovered that quickly! The cloth back can get hot pretty fast too!
Makes me wonder if my speed is too high?
 

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I understand your frustration.

You can try going back to coarser grit and slow speed. If you have any variation in diameter or lack of perfect circular shape, and have the lathe on high, the sand paper will bounce off the high spots and not contact the low spots.

No single solution for me when I have a similar problem.

I sometimes will hand sand with the grain lathe stopped.

I sometimes use a cordless drill circular sander lathe stopped. Recommended if you do not have one of these.

http://www.woodworkingshop.com/product/kd50054/

I have also used a sanding mop on my drill press. Like this one.
http://www.woodworkingshop.com/product/mi15120/

I recently purchased the Beall buffing system and sometimes just buffing with the Tripoli compound can remove scratches. I have started buffing my pieces since it is a good way to find out if there are scratches which need sanding prior to applying the finish.

http://www.packardwoodworks.com/Mer...de=packard&Category_Code=finish-beall-beal3bf
 

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"I'm sure you have found out the paper can go from room temperature to third degree burn in a blink of an eye with paper back paper."

:) Yup, discovered that quickly! The cloth back can get hot pretty fast too!
Makes me wonder if my speed is too high?
That may be more than a hint. Nature's feedback. :icon_smile:

If you generate too much heat, you may burn rather than sand. Not good for later finishing. Try slowing down the lathe.
 

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As Steve said you can dampen with water. I use mineral spirits because it does not raise the grain and dries almost instantlly.
Make sure you have a light you can shine parallel when wet. It is very difficult to see the scrathes from overhead. With the light parallel to work the scratches or other defects pop out.

I prefer the soft pads (about like a mouse pad) and psa backed paper; it seems easier to move the paper back and forth along the length. You can also hold a small strip maybe only 1/2" wide if that is all you need saving you sand paper.

For your course (1st or 2nd) sandings drywall sanding sheets work well as you can easily form them around details without destroring the detail.
 

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I feel your pain. I am relatively new to turning as well, and went through a period where my turning skills got much better but, because of poor sanding technique, my finishes were less than satisfactory.

Here is a synopsis of what I've learned:

1) Power sand whenever possible. Recommend purchasing a starter kit from Vince @ http://vinceswoodnwonders.com/store/

2) Use good quality mylar or synthetic backed aluminum oxide sandpapers when hand sanding.

3) Wipe well with denatured alcohol soaked paper towel or blow off with compressed air between grits. There are always stray pieces of the previous grit left behind, and they will scratch each successive step.

4) If your lathe has a reverse setting, use it. I frequently start sanding in both directions after 320 grit.

5) Don't move to the next grit until all the scratches left behind from the previous grit are gone. For instance, if 220 grit didn't get the surface smooth, 320 grit won't either.

6) After the last grit, which for me is 800, use a cutting wax (Dr. Kirk's or U-Beaut EEE Ultra Shine) to remove the last vestiges of sanding marks. At that point the surface should look almost as if you've already applied a finish... but don't believe it, it will dull very quickly if you don't apply a true finish. Remember though, that these products contain wax; depending on the finish, you may need to remove it with acetone, naptha, or DNA before applying your finish if that finish is not compatible with wax. Most/all oil soluble finishes (shellac, poly, or any of the "thanes") are compatible; water based finishes (such as General Finishes Woodturners Finish) are not.

Hope this helps.
 

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Excellent tips so far. As for those "rogue" scratches you mentioned...I know them well. It's like there was a grain or two of 100 grit stuck on your 180 grit paper and your 220 simply won't remove it. I am far from a sanding expert but I chalk that phenomenon up to inconsistencies in the sandpaper itself. I got a lot of that when I used tear off strips from woodcraft. Maybe I got a bad batch. For hand sanding I started buying Norton sheets from the box store and cutting them into 2" wide strips (it's great for your wife's kitchen shears). I'm sure there is better paper out there but it works well for me. I also power sand with Vince's blue disks and occasionally get the same problem, but not often. If it makes you feel better, one of the great benefits of wearing my Trend Airshield while sanding is that it muffles the profanities coming from my mouth. One day I hope to make peace with the process but I doubt I will ever truly enjoy it.
 

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All good advice so far. Now I'm not trying to be a jerk here, but if you get cleaner cuts, you could start sanding at a higher grit. Sharpen right before your last pass and see if this helps.
 

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here are a few tips Ive learned along the way. hope they help.
1. spend more time with sharp tools than with sandpaper. If you are getting really torn out grain you should consider going over it again with a sharp tool. The one exception to this is punky wood where it really doesnt matter how sharp the tool is. If the wood is sound though shoot for little to no torn out grain before you start sanding. Not only should you have a sharp tool but also research the different TYPES of cuts for different situations- rough cut scraping cut shear scraping cut etc. These cuts are used at different times in the process. Youtube Lyle Jamieson and check out some of his videos. He does a great job explaining the different cuts and why they work well at different times with different grain orientations and so forth
2. Light tool marks are ok and usually sand out pretty easy.
3. 150 is a high grit to start with especially on the inside of bowls. Glenn lucas one of the best bowl turners in the world starts out power sanding with 80 grit and moves his way up. 150 will take a long time to get out with tooling marks and torn grain. I think there is a high likelihood that it's not the 150 and subsequent grits that are the problem but the fact that the original tool marks and grain tearing have not been sanded out. Start with a lower grit like 80 to remedy the problem.
4. dont skip grits- the only one I skip from 80-400 is 180. 80-100-120-150-220-320 400.
5.low speed-the higher the speed the more heat you get. The more heat you get the more it tears up your paper. Lower speed allows the paper to move evenly across the surface and preserves the paper for longer.
6. The paper should be SHARP. This was the biggest mistake Ive made in the sanding process. There is a tendency to hang on to the paper much longer than you should. There are two goals that I look for when sanding with the first grit which are no tooling or torn endgrain marks.Once these are gone moving through the grits is much much easier but 150 or 220 is going to take ages to get endgrain and tooling marks out. As soon as the paper starts getting hot I chuck it. It may not look or feel that dull but it is and you end up spending a ton of time sanding with dull paper. Sandpaper really does not last as long as you would think.
7. go over the entire surface of the piece twice with each grit. Once you have done this the chances are that you have sanded out all the scratch marks from the previous grit.
8. Between grits take off all the dust from the previous grit. Dust from the previous grit will clog and heat up the new one so remove it with a paper towel or air compressor.
9. (And this may be a personal thing) but when I first started sanding I would stop the lathe at every grit and think to myself HO HUMMM what grit is that scratch there from? and what grit is this one from? I don't do that anymore because I'm often convinced Im not done sanding in a particular grit when I really am. The only time I stop the lathe during the entire sanding process is when I am sanding out tool and endgrain when I first start with 80 grit. Once those are gone I don't look at the wood until ive reached the last grit. If there are still sanding marks on the last one it's usually a result of the final grit and a light hand sanding with the final grit will get these scratches out. If it does not I go a little higher to 600. (Most don't go this high but I'm super ocd about getting rid of scratches)
hope this helps, happy turnin,
Bond
 

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Discussion Starter · #11 ·
Thanks for all the input; it's really helpful. I do think some of the problem with inconsistent grit in the cloth backed roll paper. I'm going to try Vince's padded abrasives; I think that will help the abrasive maintain contact with the wood. Almost everyone talked about speed. What speeds are you guys using when you sand? Are you changing speed as you go up in the grits?
 

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Different lathes will have different lowest speeds my nova runs at a little over 200 at it's slowest while some variable speeds go below 100 if you dont have a high end model lathe 200 ish works pretty well. What kind of lathe do you have? But slower the better especially on larger pieces. No need to change speed as you go up the grits
 

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Discussion Starter · #13 ·
My lathe is an old Powermatic 45. It came with a three phase motor so I added a Variable Frequency Drive. The VFD lets me dial down below 100 rpm if I want to.
 

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Agree with getting as good a finish as you can with your turning tools BEFORE heading for the sandpaper.

I sand with the lathe turning at 500 RPM. Many go slower, but this works for me. Wouldn't go faster though. Heat is your enemy when sanding.

Also, use a very light touch with the paper or discs. More pressure won't give better results, just more heat and scratching.

I agree with the stop and look mentality. The only time I stop the lathe is when I go from forward to reverse or back to forwards again.

Vince's stuff is the best bargain in sanding supplies around.
 

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A lot of talk about speed for sanding. Is there a recommended speed in inches per minute for sanding? The reason I ask is at the same RPM a 3" diameter pepper mill is going past the sand paper 3 times as fast as a 1" spindle.
Tom
 

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A lot of talk about speed for sanding. Is there a recommended speed in inches per minute for sanding? The reason I ask is at the same RPM a 3" diameter pepper mill is going past the sand paper 3 times as fast as a 1" spindle.
Tom
The outer portions of a piece will be going much faster than the inner portions. I do not try and calculate velocity at a given point.

I think it is easier to consider RPM's and then the heat. Lighter pressure should mean less friction and so less heat.

On my lathe 250 rpm and 500 rpm are two presets. I tend to use one or the other depending on the diameter of the piece.
 

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I don't think the exact speed really matters. Main point is, don't go too fast. Also, I've heard it said that the speed of your power sander should be about 1.5-2 times the speed that the wood rotates. Don't know where that came from, but I've heard it more than once or twice from some well respected sources.

For me, 500 RPM works fine regardless of size, unless it's something really large (say greater than about 10 inches). If that big, I turn it down to about 250-300 RPM.
 

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As I've mentioned in prior posts, I'm new to turning. I love turning things, mostly pepper mills and pens so far, but sanding is driving me nuts. I know most people don't enjoy it, but I'm hoping there are some tips that will help me out. My chief problem is that I get a lot of cross grain scratching that's very hard to get out. I'm using the cloth backed rolls that are sold as the woodturners multi-roll sanding kit. I start at 150 and work my way through the grits, but invariably, I get a "rogue" scratch that isn't removed by the next grit. I get that sanding on the lathe is by its nature cross grain sanding, but jeez, there's got to be a better way. Am I sanding a too high or liw of a speed? Please help with some of those sage tips that make me go "oh,,,that's the trick! Thanks.
Quickstep, I was in the same boat as you, sanding drove me nuts...
Here is what I did to solve the issue, never looked back.
http://www.rocky-roost-woodturnings.com/wood-turning-blog/sanders-you-can-make-yourse.html
Check it out...:eek:
 

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Besides all of the above when I bother I also stop the lathe and sand with the grain for those scratches that seem to defy the paper. On some things that would not snad out in just a few seconds of sanding with the grain all is good.
 
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