Circular patterns on CA finish after wet sanding

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Ribaaa

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Recently I have noticed that after I finish wet sanding with MM up to 12000 I have circular patterns on my pens.
Any idea or suggestion on how to avoid that, it's really ruining the pen.
20210928_233804.jpg


Thanks a lot.
 
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magpens

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I may be "off base" here . . . . Not sure of your actual sanding technique / method .

I sand lengthwise with the lathe power off . . . . not around the circumference of the barrel while it is turning.
 

CjG78

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The secret to a perfect ca finish is to wet sand all of the shine off after applying about 8 coats using 800 grit wet and dry. Then work up the paper sanding laterally each grit to remove the radial lines. Then my favourite quick and no fail polish is brasso, a liquid metal polish, applied to paper towel and gently rubbed for a few minutes, then buffed on a buffing wheel
 
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CjG78

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It seems as though your preparation before using your micromesh wasn't enough. Really important step before micromesh/paper is to get a completely dull and smooth finish. Check against the light also by looking down the barrel closely, looking for radial scratches.
 

Penchant 4

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I may be "off base" here . . . . Not sure of your actual sanding technique / method .

I sand lengthwise with the lathe power off . . . . not around the circumference of the barrel while it is turning.
With each grit, try sanding circumferentially (lathe running) and then longitudinally (lathe off). The changing direction of the scratch pattern is an indication of whether the whole piece is uniformly sanded. $0.02.
 

KMCloonan

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It sort of looks to me like ridges from applying a thick CA while the lathe was turning, but then not leveling the ridges with light sanding before putting more CA on. (I guess that's what the other guys are saying as well.)
 

egnald

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I used to apply thicker layers of CA using closed cell foam as an applicator and had the same kind of thing happen. Then I would sand the ridges off using 400 grit sandpaper backed by a hard and flat surface (an acrylic blank). Occasionally I would experience the dreaded sand-through.

Since then, I have been sacrificing CA by discarding a lot that soaks into my paper towel applicators. I have to put on more coats, but they are much thinner. Since changing my regimen to this, I have not had any more issues. In fact, I go from CA directly to wet sanding with MicroMesh as the thin coats provide a surface that is smooth and has no ridges that need to be sanded off. For prep though before CA I still use 400, 600, and 800 grit sandpaper backed with the acrylic blank so that there are no high and low spots before I apply the CA.

There are a lot of experienced folks on IAP that successfully use all sorts of different techniques and applicators. I'm sure you will find a technique that works for you once you figure out for sure what is behind the problem.

Regards,
Dave
 

jrista

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It seems as though your preparation before using your micromesh wasn't enough. Really important step before micromesh/paper is to get a completely dull and smooth finish. Check against the light also by looking down the barrel closely, looking for radial scratches.

The dull, smooth finish after initial sanding is pretty key. My first few CA finishes, I didn't fully sand down the bumps and ridges, and those stick around once you start wet sanding/polishing. Flattening out any imperfections in the CA before polishing it up was the key for me.

The other key for me was the lateral sanding, although, I tend not to do that until the last few of micromesh grits, as before that it seems like each grit is enough to cut through the prior grit radially. I guess YMMV here, but sanding radially, then laterally, then radially, then laterally with the last few grits seems to do the trick for me.

I finish up with a polish...I've been trying a lot of those. Not sure I've found the one that works best for me yet...although, I haven't tried any metal polishes yet.
 

CjG78

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The dull, smooth finish after initial sanding is pretty key. My first few CA finishes, I didn't fully sand down the bumps and ridges, and those stick around once you start wet sanding/polishing. Flattening out any imperfections in the CA before polishing it up was the key for me.

The other key for me was the lateral sanding, although, I tend not to do that until the last few of micromesh grits, as before that it seems like each grit is enough to cut through the prior grit radially. I guess YMMV here, but sanding radially, then laterally, then radially, then laterally with the last few grits seems to do the trick for me.

I finish up with a polish...I've been trying a lot of those. Not sure I've found the one that works best for me yet...although, I haven't tried any metal polishes yet.
Absolutely mate. To me and my thinking, the more coarse grit need to be laterally sanded as the finer you go, the harder it is to remove the radials, you might not see it as your eye generally can't see past 600 grit, but once you polish, they are magnified. But, everyone has a great method that works for them.
I spent countless hours trying to perfect my finishing techniques. Oh the pain! But so worth it! Once you do your first glass finish, it's hard to settle for less. Metal polish speeds up the shine. Must lateral polish also.
 

TonyL

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I do not think you sanded long enough or with grits low enough before proceeding to the next grit. I would hit it with 400 (320 if you think you have enough CA).
 

jrista

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Absolutely mate. To me and my thinking, the more coarse grit need to be laterally sanded as the finer you go, the harder it is to remove the radials, you might not see it as your eye generally can't see past 600 grit, but once you polish, they are magnified. But, everyone has a great method that works for them.
I spent countless hours trying to perfect my finishing techniques. Oh the pain! But so worth it! Once you do your first glass finish, it's hard to settle for less. Metal polish speeds up the shine. Must lateral polish also.
Yeah, the more I work with either CA or resin blanks, the more I'm finding out how hard it is to truly get that polished glass like look. The lighting has a lot to do with how much you can see...and what may look glassy on the lathe, can easily end up looking like a scratched up mess under different light. Its a challenge, for sure. I'm still figuring it out.
 

CjG78

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Yeah, the more I work with either CA or resin blanks, the more I'm finding out how hard it is to truly get that polished glass like look. The lighting has a lot to do with how much you can see...and what may look glassy on the lathe, can easily end up looking like a scratched up mess under different light. Its a challenge, for sure. I'm still figuring it out.
Couldn't have said it better myself!
 

MPVic

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If I'm not mistaken, Lee posted here a while back about a finishing process that I have found very effective. He builds up his CA finish and then using a sharp skew as a scraper reduces the diameter to suit the hardware. Solved all my problems of getting the ridges out.
 

NGLJ

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I had similar problems at first. I was using medium CA. It builds faster but can leave more bumps. Since I switched to only using thin CA and applying multiple coats cured with accelerator AND letting it get really set hard I have had few problems. I apply CA after sanding to 600 with Abranet and then I wet sand with 400 & 800 to smooth out any bumps. Then I start with micromesh to 12000.
 
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