I NEED Your Help, Please

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DrD

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As I turn my blanks, when the final profile is achieved, I remove the turned blanks from the lathe, and do all sanding by hand, longitudinally, with the grain, As stated in other recent threads I typically go 320 grit, 400, 600, 800, then switch to MM, 2400 thru 12000. All done by hand, with the grain. When I finish, there are ABSOLUTELY no RADIAL marks on the blank as seen with the naked eye and with a 20x loupe.

Then comes the finishing. Opting to use friction finishes, it is back to the lathe. RPMs? I have tried low, ~700, and I've tried high, ~4000. No matter what speed, nor how I apply the finish - clean cotton, clean blue shop towel - I get radial ridges, almost like sanding marks. HELP! Please!

Any and all suggestion are appreciated.

Don
 
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Although many don't use a friction finishing agent, those same things can occur regardless of the agent (ie, you are not alone!). Suggest you keep the blank on the lathe and try sanding with a rather light touch. RPM's shouldn't be high, probably better at a low speed. Try starting out with 600 or even 800 and progress up through MM as you did before. You may experience sanding through the finish. If that happens, try more coats of finish before sanding.
Hope this helps.
 
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DrD

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Thanks Ted! One of my graduate students went on to teach at THE university for a number of years before returning to Arkansas. He loved it up there.
 

Mr Vic

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Are you wiping on finish and allowing it to soak in a bit before turning on the lathe. When you turn on the lathe are you moving the applicator of choice back and forth the length of the blank? If you hold in one place it could cause ridges. Being Friction Polish speed is your friend and you should feel some heat build up.

On your sanding I think you are overdoing it. I leave the blank on the lathe to sand while turning at slowest speed. Between grits I turn off and sand length wise. On wood I rarely go above 800 grit. The micro mesh without a finish is a waste of time and micro mesh in my opinion.
 

DrD

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Thanks Vic. I am not currently letting the polish soak in.
Yes, I am moving the applicator back an forth, the full length of the blank.
Just today I started working with the Mirlon system I got from BHW: Red, Black, Tan and that looks promising.
Thanks
 

Humongous

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When I use Hut Crystal Coat I only use a few drops per coat and apply it with the grain turning the blank by hand. Then turn the lathe on and "pinch" the blank with the towel and slowly move back and forth to generate heat to set the finish. I have found that any more than a few drops can cause the ridges that you mention. I also run at my lowest speed around 500.
 

leehljp

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I don't know how fine you can use a scraper or radiuse carbide insert on the blank, but I regularly can take .001 or .002 thickness off of either the wood or the finish. That said, if I have ridges, which I do get on occasion, I just use the scraper/radiused carbide insert to cut of the ridges and smooth it down to level with everything else. And the smoothness is equivalent of 6000-8000 on MM.

BTW, I think it is probably a technique issue. I never sand WITH the grain and I too use a loupe. Can't find radial ridges or swirls in the wood or finish.
 
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DrD

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BTW, I think it is probably a technique issue. I never sand WITH the grain and I too use a loupe. Can't find radial ridges or swirls in the wood or finish.
Thanks, so frequently some of us - me - mistakes "fine craftsmanship" for a lotta added work to cover up poor technique. I am a front row member of that club. To better my technique, I need to take very light passes when finishing with skew, when sanding and when applying finish. What speed do you run your lathe?
Thanks for the tip!! This is exactly the kind of help I was hoping to receive!!
Don, and fellow Mississippian
 

TonyL

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As silly as this sounds, can it be that there are radial scratches, but you don't see them until you polish them more? Many times I was convinced that I didn't see any scratches after 2000 grit. Then I apply some polishes and the radial scratches are revealed (although they are shiny now :) ).
 
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leehljp

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Thanks, so frequently some of us - me - mistakes "fine craftsmanship" for a lotta added work to cover up poor technique. I am a front row member of that club. To better my technique, I need to take very light passes when finishing with skew, when sanding and when applying finish. What speed do you run your lathe?
Thanks for the tip!! This is exactly the kind of help I was hoping to receive!!
Don, and fellow Mississippian
2000 - 3000 rpm when using the scraper. Since I do mostly segments, and segments usually smear when sanding, I don't sand on segments.
 
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