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Thread: Inside of bowl sanding problem

  1. #1
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    Inside of bowl sanding problem

    My biggest disappointment with turning small bowls is getting the sandpaper scratches out of the radious on the inside where bottom meets side. What am I doing wrong? I've tried those sanding balls from HF and turn it sideways and rotate it as I turn the bowl on the lathe. Nothing seems to help.

  2. #2
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    Bill,
    Without seeing photos we can only make guesses.

  3. #3
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    You're right. I was turning last night and was to discusted to load pics. I'll get pics.
    But it's in the curl where I sometimes cut back under the rim. Going to have to settle for straight sides I guess.

  4. #4
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    As you can see I cut the bowl beyond the diameter of the lip. This is the only place I struggle with.
    Attached Images Attached Images

  5. #5
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    Those are scratches from your gouge. You need to use the famous 80 grit gouge and get those out. Or drop the handle of your gouge down and rotate the gouge as you transition. Depends on the angle you sharpen the gouge. Or use a scraper. Nice job though! How did you get the rim a different color?

  6. #6
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    Looks like compression caused by the heal of your gouge. You can try using some water to raise the grain, then sand again but most likely, you will have to turn that area again. What grind are you using on your gouge??
    Steve

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  7. #7
    I use these sanding discs from Lee Valley http://www.leevalley.com/en/Wood/pag...53&cat=1,42500 as you can see from the picture on the web page the scalloped edges bend over the side of the sanding pad and do a great job on the area that you are having trouble with...

  8. #8
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    Quote Originally Posted by Kyle Iwamoto View Post
    Those are scratches from your gouge. You need to use the famous 80 grit gouge and get those out. Or drop the handle of your gouge down and rotate the gouge as you transition. Depends on the angle you sharpen the gouge. Or use a scraper. Nice job though! How did you get the rim a different color?
    I think it's just because you are looking down from the top so the flash hit the rim at a different angle.

  9. #9
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    Quote Originally Posted by Barry McFadden View Post
    I use these sanding discs from Lee Valley http://www.leevalley.com/en/Wood/pag...53&cat=1,42500 as you can see from the picture on the web page the scalloped edges bend over the side of the sanding pad and do a great job on the area that you are having trouble with...
    Thanks Barry. That looks just like what I need.

  10. #10
    I agree with Steve. Those marks are from your gouge. Grinding the heel off your gouge can help mitigate them, use of a "bottom feeder" gouge may make a difference in that transition area. That transition area is prone to compression marks as well as a little minor tear out as you go from cross grain to end grain across the bottom of more flat bottom bowls.

    Sanding aggressively will eventually take them out but will often create a depressed area as they are generally quite deep and troublesome.
    Sanding with drill press and soft backing pads makes this area easier to target if that helps. (All my sanding is done on drill press rather than on the lathe)

    Scallop edged pads will help sand that area but not the root of the problem
    Jim

  11. #11
    Quote Originally Posted by Bill Jobe View Post
    ...where bottom meets side...
    Ideally, there is no such spot. The inside (and outside) of a bowl is more appealing, and much easier to turn if it is a fair curve. In that situation there would be no discernible point of transition or change in the curvature.

    That doesn't help your present situation, but it may help with the next bowl.

    Left click my name for homepage link.

  12. #12
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    You have got some good comments and things to try. As Steve S mentioned, try wetting that area. It'll raise the grain and possibly get rid of the compression.

    When I have circular lines from sanding on the lathe, I found that it is best to stop sanding on the lathe. When I've had those same sanding lines, I'll hand sand either 90 degrees from the direction of the lines or with the grain. I keep sanding until they're gone. I won't jump up to finer grit if they are still there. I've found that they come out easier that way. Also, I've used some 2" soft pads on a self-powered sander and a drill with moderate luck - - you just need to be careful about the sandpaper edge causing more problems than it is fixing. A soft sanding medium like Abranet helps.

  13. #13
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    With the lathe shut off. Power sand the area rotating the bowl back and fourth. Use an 80 grit disk with a mandrel a 1/4" smaller than the disk. It will help the disk bend into that tight curve. Next bowl follow John's suggestion.
    Member Illiana Woodturners

  14. #14
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    If you're having trouble cutting this area clean with a bowl gouge, it's much quicker and more efficient to use a negative rake scraper than sanding to remove the tool marks. It takes quite a bit of sanding to remove marks like those since the wood has been compressed by the heel of the gouge. Many times if you try to sand, you can create dips from working an area too much which messes with a smooth inside curve. If you must sand using 80 grit, using a soft backup pad with the lathe off will "softly" sand the area without digging in and creating divots.

  15. #15
    You can often clean that up with a "shear" scrape. Use a sturdy, round nose 1/2" or 5/8" scraper angled at 45 degrees. Usually you pull from the inside but sometimes you'd push. It can be tricky, though, so practice on something with a nice firm attachment and thick walls (like when you're roughing) before attempting on a nearly finished piece. It can be a little tricky depending on how sharp your transition is.

    Like this (you don't need their tool to do it...):



    I'd start at about the 2 minute 10 second mark.

    After that you just gotta break out the power sanding.

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