Radial scratches and buffing wheels

[Hippie3180]

So, sometimes I have issues with radial scratches still being visible(especially on black blanks.) I use micro mesh with water, also I turn my lathe off and sand horizontally between each pad and I still see radial scratches when done, not always but sometimes. Oh! And I do use plastic polish at the end.

I don't own a buffing wheel yet, would it greatly minimize this sort of thing, OR am I doing something wrong?

 

[derekdd]

What grit are you starting at and what kind of sand paper are you using?

 

[Hippie3180]

What grit are you starting at and what kind of sand paper are you using?

I usually sand my blank before ca using 220 to 400 , then once I ca I micro mesh 1500 to 12000 using water. Then I get a microfiber cloth and buff with plastic polish. Typically this creates a very shiny finish where scratches aren't visible to my eye, but sometimes I have issues esp with black.

 

[derekdd]

I usually sand my blank before ca using 220 to 400 , then once I ca I micro mesh 1500 to 12000 using water. Then I get a microfiber cloth and buff with plastic polish. Typically this creates a very shiny finish where scratches aren't visible to my eye, but sometimes I have issues esp with black.

Okay, depending on the wood, 220 might be too fine to remove the tool marks.

It sounds like perhaps you have some tool marks left from turning. Depending on the wood, I typically start with 180, but with splintery wood like Wenge or Bubinga, I'll start with 120. I find I can usually get away with starting with 240 on Alumilite blanks if I've done some very fine shear cuts at the end to leave a fairly smooth blank.

Your post CA process is just like mine.

 

[Hippie3180]

Hmm, so I may be seeing scratches from my skew that I didn't get out. I'm working with Black Walnut…a somewhat prominent grain.

The scratches really appear to be in the ca though.

 

[EricRN]

I'm guessing you aren't sanding enough at one early stage. I sand radially first. Then turn off the lathe and sand longitudinally until all of the circular scratch marks are gone. Then radially with the next grit until all of the longitudinal marks are gone, and so on.

I've found that, if I'm not careful to make sure all of the marks from the prior sand are gone, I'm left with radial scratch marks when I polish.

 

[derekdd]

Hmm, so I may be seeing scratches from my skew that I didn't get out. I'm working with Black Walnut…a somewhat prominent grain.

The scratches really appear to be in the ca though.

Do you use DNA to wipe down your blank say, after 400-600 grit?

With a decent light, you should be able to pretty easily see if you still have tooling marks by those grits.

 

[Hippie3180]

Do you use DNA to wipe down your blank say, after 400-600 grit?

With a decent light, you should be able to pretty easily see if you still have tooling marks by those grits.

I do use denatured alcohol before applying ca. Honestly, I don't really check as I have pretty much assume I have done a adequate sanding job, esp with wood. I suppose this could be my downfall. I am one who enjoys the task of sanding and feel as if I'm very thorough, but it is a possibility that I'm not.

 

[Hippie3180]

I'm guessing you aren't sanding enough at one early stage. I sand radially first. Then turn off the lathe and sand longitudinally until all of the circular scratch marks are gone. Then radially with the next grit until all of the longitudinal marks are gone, and so on.

I've found that, if I'm not careful to make sure all of the marks from the prior sand are gone, I'm left with radial scratch marks when I polish.

I do sand with lathe on them turned on horizontally to rid the blank of radial scratches. I typically can't see very well during the process if I have eliminated all the radial scratches. I guess I can improve my lighting and get magnification so I can see things during the process.

 

[egnald]

I rarely see any tool marks in wood when I am finished turning. I typically get the blank round using a round carbide cutter held at 60-degrees instead of 90 (the tool is fastened to a hex shaft and works very much like Tshadow's Magical Skew). Once round, i switch to a round carbide cutter at 90 degrees until I get very close to the finished dimension. I then take one or two light passes with a square-radiused corners cutter to even things out. I find it very rare that there are any deep tool marks that need to be sanded out. (Although I use carbide, I have heard the same from many turners that use a sharp skew as well).

I typically start by sanding wood lightly at 1000 RPM using 400 grit backed by a flat "acrylic" blank to keep things level. Then I sand inline with the lathe off. I follow the 400 grit with 600 and then with 800 before applying a finish.

On very rare occasions I have started sanding with 320 grit, but it is very rare.

For plastic blanks I do not sand at all - I just do wet sanding using MicroMesh. With MicroMesh however, I do double up on the first, most coarse, grit. I simply have two of those (their number 1500, rust colored ones) on top of my stack of MicroMesh pads.

Regards,
Dave

PS. When sandpaper is pushed across a piece of wood, the abrasive grains cut tiny shavings out of the surface. To the naked eye, these shavings look like dust, but magnified, the are just like the shavings produced by other tools. That is why sandpaper is considered a cutting tool.

 

[Smokey S]

You may also want to be sure that your sand paper is not loading up and wipe the sanding dust before moving on to the next grit. I am still very much a newbie myself, I have slowed my lathe down all the way( approximately 300 rpm) when dry sanding. Keep at it, you will get it! ……Smokey

 

[Hippie3180]

I will try these things to see if I get better results, I don't always have issues, just on occasion and my process is always the same.

 

[Todd in PA]

I believe you said the tiny scratches are in the CA and not the wood.

I used micromesh only for a long time and often wet sanded to 12000 two or three times chasing out those scratches. They never seemed to go all the way out no matter how much or carefully i did the job. On a black background ALL you see is the surface and every imperfection shows. The surface is equally scratched on other colors, but doesn't show up as much.

Ultimately I got some buffing wheels and compounds. Now I wet sand much quicker and can count on the buffing to give me a great scratch free surface.

 

[Hippie3180]

I believe you said the tiny scratches are in the CA and not the wood.

I used micromesh only for a long time and often wet sanded to 12000 two or three times chasing out those scratches. They never seemed to go all the way out no matter how much or carefully i did the job. On a black background ALL you see is the surface and every imperfection shows. The surface is equally scratched on other colors, but doesn't show up as much.

Ultimately I got some buffing wheels and compounds. Now I wet sand much quicker and can count on the buffing to give me a great scratch free surface.

That is kind of what I was wondering how much a buffing wheel would take out? Does it pretty much get rid of the tiny scratches left from micro mesh. Is it worth the money to deal with the minute scratches that are left? Yes, black just appears to be all buggered up after micro mesh, and I really don't see the tiny scratches on acrylic.

 

[Penultimate]

I think it is worth buffing. I primarily turn resin and find that buffing after micro mesh makes it look shiny. Check out Caswell Plating for buffing supplies and tips. https://caswellplating.com/

 

[jttheclockman]

So, sometimes I have issues with radial scratches still being visible(especially on black blanks.) I use micro mesh with water, also I turn my lathe off and sand horizontally between each pad and I still see radial scratches when done, not always but sometimes. Oh! And I do use plastic polish at the end.

I don't own a buffing wheel yet, would it greatly minimize this sort of thing, OR am I doing something wrong?

I read through your question and follow ups and here is what I am understanding, you have radial scratches in your CA finish and is noticable mostly on darker woods. I do not see anywhere that you say you sand the wood before applying CA and I do see where you say you maybe seeing tool marks under the CA. To combat this and being you are not doing any type segmenting where sanding dust can contaminate the lighter woods, I suggest you finish the blank with some light sanding and depending on depth of scratches I would start with sandpaper no lower than 400 grit. If deeper then you need to do a better job with tooling. But sanding with 400 grit and then 600 grit will give you a nice surface to apply CA. Make sure to sand vertical (with grain) also Wipe blank down before each grit change. When done wipe with acetone or DNA (denatured Alcohol) I do not recommend rubbing alcohol. They are not the same makeup.

Now you are ready to finish with CA. Here is one of those how good are you questions and only you can answer. How good is your application of CA and do you need to sand before MM. I do not know about you but I have been doing this for over 15 years and never ever have I been able to go from CA finish to MM without sanding. Not ashamed to admit and nor should you. For this I recommend starting with 1200 grit wet dry black sandpaper and go to 1500 and then 2000. After this you should now not see any shiney spots on the blank from CA spots you did not touch with sandpaper. Also run your fingers over the blank and feel for ridges or hills and valleys. Your finger tips are the best tool for this because they are very sensitive to touch. If you have large ridges from CA then I highly recommend you wrap the sandpaper around a flat blank surface. I have a 2" wide piece of hardwood about 6" long by 3/4" thick for this. Again after each grit I sand with grain and wipe with a wet towel. All sanding of CA is done wet with clean water and the lathe bed covered to protect from rust. After 2000 grit I now start MM and go through all grits and wipe each grit.

Now finishing with polishes is a topic that everyone has an opinion and may differ so I will stay out of this. As for polishing wheels I do not believe in them. I will say this if you go that route beware you can polish right through a finish in an eye blink depending of layers of CA. I do not like to build my CA up. I use 3 to 4 coats of thin to seal blank and then 4 to 5 coats med to get me to my sanding stage. I am aware of my abilities to sand and polish with MM from there. You too will get to that stage the more pens you make. Good luck. This is my thoughts on the subject.

 

[leehljp]

I agree with John T. and his detailed method. It works. There are other methods that will work as mentioned, and I also have a different method that I have to use on segmented blanks of different colored woods and metallic separators.

As to getting radial scratches from the tool, if that is what is causing them, - then practice is sharpening should help. I am one who goes from the tool to finish without the need for sanding any blemishes out. The method for that is a pristine razor sharp tool and light touches. I don't have magic hands, it is the sharpness of the tool and light touches that produce super smooth finishes that only need polishing at the most. And when I do use SandPaper or MM, I don't start with anything less than 400, and usually 600. Anything below 400 will add deeper scratches that takes more sanding to get out.

 

[RunnerVince]

Do you use DNA to wipe down your blank say, after 400-600 grit?

With a decent light, you should be able to pretty easily see if you still have tooling marks by those grits.

I second the use of a decent light.

The scratches are either in the finish itself (unlikely in this case), or they were there before you put the finish in and you simply didn't see them. The raking light will do wonders for that.

In contrast to what others have said, you may be starting at too low of a grit. If your tools are sharp, clean, and free of dings, they shouldn't be leaving substantial tool marks in most materials (particularly walnut), and 300-600 grit may be sufficient to remove those marks. Starting at anything less than 300, I find that I think I've gotten the scratches out, then I get up two grits and see something I missed, then have to go back and forth.

 

[jrista]

I usually sand my blank before ca using 220 to 400 , then once I ca I micro mesh 1500 to 12000 using water. Then I get a microfiber cloth and buff with plastic polish. Typically this creates a very shiny finish where scratches aren't visible to my eye, but sometimes I have issues esp with black.

So, my thought is, 220 is too COARSE. For say, a wood bowl, or vase, 220 is a fine starting point. Unless you are REALY rough with your tooling, though, for pens, I never start lower than 400. Sometimes, if I turn smoothly enough, I'll start at 600.

A grit of 180, IMO, is all but guaranteed to leave you with radial scratches. You can keep going back to 180, but that will take off more and more material, which could drop you below the diameter of your fittings. I would START at 400. Maybe you spend a bit more time at 400, to really clean up the tooling marks, then just blaze through the rest, then spend the necessary time on the last grit or two, to get the kind of finish you want.

I had scratch problems, especially with resins, when using coarser grits. That stopped when I started using 400 as my minimum.

 

[Gary Beasley]

As far as inspection lights go a small bright spot type light will show imperfections a lot easier than the usual diffused light you would get from a shop light. A point source will create sharp edged shadows when raking across a surface with defects.

 

[Todd in PA]

Like several others have mentioned here, I don't sand the wood. I make a final pass with a square carbide at a steep scraping angle that leaves no tool marks. Then go directly to applying finish.

For what it's worth, sanding the wood will diminish or eliminate any natural luster or chatoyancy that the wood might have.