circular sanding scratches

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crashgtr

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Apr 22, 2006
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Hillsborough, nj, USA.
I am struggling with circular sanding scratches and I am not sure if I am being too anal or if I am just not that good at pen finishing yet.

I sand my blanks with the lathe on then with the lathe off for each grit, making sure wipe the blank down with Denatured Alcohol between each grit. I have a strong LED light which sits on the head stock so I can clearly see the blank's surface.

It looks like all the circular scratches are gone until I whip out my magnifying glass.(i do this between each grit)

Should all the circular scratches be invisible under a magnifier?

I want to see some of my pens but with the circular scratches seen under the magnifying glass I am not sure if they are good enough quality to be selling.

Any advice is greatly appreciated.
 
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Talltim

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crashgtr; I sand my blanks with the lathe on then with the lathe off for each grit said:
By saying you are sanding with the lathe off I assume you mean you are sanding lengthwise with the blank.

The test is at the end.

You are probably being hyper critical of your work. With enough magnification a hair can look like it has craters in it. We always ask the question, would I be happy if I bought the pen?

For us the skew is the answer not sandpaper. We hardly ever sand.





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JimB

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What grits sandpaper are you using, what brand of paper and what magnification are you using?

Are you sanding the wood or the finish? Is the problem specific to a species of wood or type of finish or do you get the scratches all the time?
 

mark james

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Try mightly to start sanding at the highest grit (and yes, master a skew, or magical skew, or carbide on the side, etc). For me, if I get too aggressive with the lowest grit and put in deep scratches - I'm toast. Very difficult to get them out. So get your tool control down to start with a higher grit, and be gentle with the sandpaper.

I also do NOT use sandpaper very often, I use abranet and have been much happier with the finish.

Keep at it - and Have FUN!
 

jttheclockman

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Throw the magnifier as far away as you can.:smile::smile::smile: We are the worst critics when it comes to our work. How many people do you see walking around shows with loops in their pockets??? I learned long time ago if I can not see scratches with the naked eye I am golden. As said if you want to see scratches you will just keep increasing magnification.

As to your method it is hard to say what you are doing wrong because we do not have enough info. You should never have to start sanding with anything lower that 400 grit and preferably 600 grit. Always stop lathe and sand lengthwise after each grit. As you go up the scratch pattern should be getting smaller. That is what sandpaper does. Yes wipe each grit off so when you go to next higher grit you do not have grit from previous paper. Take it easy on yourself. You will get better. As someone mentioned learn to use a skew and do away with sanding all together. :smile::smile:
 

magpens

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You didn't say what material you are sanding, and that matters. . Wood, acrylic, cured CA ?????

In my opinion, having done about 1500 pens, once you start the final finishing your LATHE SHOULD BE OFF.

If you sand with the lathe on, you will make scratches deeper than you think.

During the finishing process, the sanding should be lengthwise only, in my opinion. . Lighter strokes as you increase the grit number.

Turn the headstock by hand between the lengthwise strokes.
 
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TonyL

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If you want to get rid of them while examining with a 10 or 20x loupe, it is very doable.
Sharp tools, planning cuts, sanding, polishing/buffing (chemically and mechanically..whatever suits you). The same way you removed the tools marks (which are just large scratches), you can remove the radial scratches. There are hundreds of ways to approach this. Of course, if you are happy with the results you are getting; there's nothing better than that.


Perform a search on "radial scratches" or "fine scratches" and you be presented with dozens of ways that many have found to make their pen look the way they want.

My own personal objective, given I am basically just turning something square into something rounds, is to focus of the finish. However, that is just my objective for the pens that I turn. Enjoy the journey!
 

Dr_N

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You didn't say what material you are sanding, and that matters. . Wood, acrylic, cured CA ?????

In my opinion, having done about 1500 pens, once you start the final finishing your LATHE SHOULD BE OFF.

If you sand with the lathe on, you will make scratches deeper than you think.

During the finishing process, the sanding should be lengthwise only, in my opinion. . Lighter strokes as you increase the grit number.

Turn the headstock by hand between the lengthwise strokes.
I had previously read in other posts, and finally used, Mal's suggested sanding technique and it made a huge difference in the finish quality of my pens. Now I only sand parallel to the mandrel and with the lathe off when finishing, and it has definitely made a noticable difference in my finished pens. No more circular scratches! I also use novus 3, novus 2, and PlastX after sanding to get a nice shine.
 

leehljp

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It all is a matter of technique, practice and experience. I do the opposite of what most have said here and get perfect finishes. And while John is correct about what the eye can see, I do use a loupe in my brightly lit room.

I do not turn the lathe off and then sand end to end. With the right finishing material, the same can be attained as the lathe turns at 500 to 700 rpm. It is all a matter of what your experience is and which techniques work best for you and your ability. Like John, I do not start below 400 and often start at 600 sandpaper equivalent.

I use polish and some microfine automotive polishes often, some with .5 or .3 micron and then a polishing cloth. No swirls.

As to the use of a loupe. I found that with my eyes, when inside with daylight (5000k) LED lights, I do need a loupe to examine my finer pen finishes. The reason is, that the 5000k (daylight) bulbs do conceal the finest scratches that only a loupe/magnifying glass can show. HOWEVER, if I take the finely finished pen out in REAL daylight, suddenly I can see minuscule things that I could not inside of my well lit shop. The Loupe/Magnifying glass show me inside - what I can only see in real daylight without the loupe. Now John doesn't need the magnifying glass as he has better eye than me - his eyes are younger than mine. :biggrin:
 

jttheclockman

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I do doubt your thoughts about my eyes Hank.:smile::smile: But here is my theory on the loop thing. Show me a pen that does not get scratched when put into use. if that was a $1000 pen then yes step up the finish. But unless that pen gets put in a show case it will get scratched from wear. At least i do try my best to polish to a clean shine but not going to fuss over scratches that I need a loop to see. Just me and my method.

I do not agree with sanding end to end only. You leave the chance for high spots. Spinning a blank at low speed and with a backer behind the sandpaper is the way I sand when I have to sand which is not too often. I like my skew. As always many methods and use one that works for you. No right or wrong way in anything we do in this hobby.
 

crashgtr

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Hillsborough, nj, USA.
scratches

Thank you all for the great advice.

I am thinking I am starting with too low grit and need to work on my turning skills to get a better cut. I think I also need better lighting because it will look great on the lathe then when i go to put it together in another pat of the shop, i sometimes see the circular scratch marks.

I use abranet and micromesh with carbide tools.

I have been using gluboost on my wood pens as a finish and I really like it.

I will keep practicing and start using my skew for finishing cuts.

Thanks again!
 

More4dan

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After spending many hours hand sanding knife blades where scratches easily show I’ve learned a bit about getting scratch free results. I change directions with each grit. Lengthwise until all radial scratches are removed. Radial with next higher grit until all linear scratches are gone. Continue through the highest grit you have, 12000 micro mesh for me. Then to the buffer with pink rouge and I buff in both directions. This is for CA and plastics.

If you sand in both directions with the same grit you can hide the scratches created from the lower grit sanding. Better to alternate. You want to only see scratches in one direction. A quick trip to the buffer will show scratches between grits. If I’m having trouble getting scratches out I drop down a few grits and start again.

Danny


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mmayo

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Tehachapi, CA
Thank you all for the great advice.

I am thinking I am starting with too low grit and need to work on my turning skills to get a better cut. I think I also need better lighting because it will look great on the lathe then when i go to put it together in another pat of the shop, i sometimes see the circular scratch marks.

I use abranet and micromesh with carbide tools.

I have been using gluboost on my wood pens as a finish and I really like it.

I will keep practicing and start using my skew for finishing cuts.

Thanks again!
Best of luck with your scratches. I never sand with any grit below 400.
 

Wildman

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Jacksonville, NC, USA.
Some rules I live by:

Buy & use quality sand paper.

Stopped buying assorted sand paper rolls in a box w/cutter after my first box. If you like them stay with it!

Dull sand paper is never the next higher grit, when dull throw that stuff away.

Before start sanding inspect the surface to be sanded start with highest grit you can. Starting with a too coarse grit sandpaper only makes more work.

Don’t press too hard when sanding!

Bought many years ago and long since worn out use these sponge pads to keep me from using too much pressure. Have cut up a few to meet sanding task. Cannot find them anymore in big box store, but that’s okay. Old mouse pads will serve just as well.

https://www.amazon.com/Sanding-Sponges-Superfine-Ultrafine-Microfine/dp/B01F7Y384S?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B01F7Y384S

If you are seeing scratches with naked eye after sanding to 400 grit something is wrong with your technique. Whether sanding with lathe on or off have drop back to lower grit sand paper to remove those scratches.

Question asked, “about what is being sanded” really should be answered so can specfic help! Some wood species shouldn’t have to go past 320, some extoic woods might reqire going to 3000 grit. If butchered the wood with dull tools might have to start with 100 or 120 grit to remove tool marks.

Most professional finishers never sand wood pass 180, 240, 320 grit and seldom use 400 grit paper or higher unless finishing the finish.

Acrylics have start wet sanding with 500 grit micromesh and run thru grits to polish.

Have never turned bone or antler blanks so no help there.
 

donstephan

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Jul 24, 2016
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Cincinnati Ohio
My experience has been, when sanding with the lathe on, speed greater than about 300 RPM leaves circular scratches that are much harder to remove.

A "raking" light, one pointed along the surface rather than into it, is more likely to show scratches as shadows.
 
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