Why is this happening to the wood???

Discussion in 'Newbie' started by Duane A Ross Jr, Nov 17, 2010.

  1. Duane A Ross Jr

    Duane A Ross Jr

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    This piece was turned once, looked nice, but I ruined it by drilling a depth hole straight through the bottom. So it sat out for a day and warped a little, so then I microwaved it to dry it out quicker to just use it as a learning piece, warped more. So when I was rounding the outside again, instead of a smooth finish, it looks as if the wood is being torn out instead of cut. I believe it is from 1 and only 1 reason. So what is your educated opinion on why it is doing this.
    Take a look at the pic attached.
    Thanks for the help.
     

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  2. Dick Sowa

    Dick Sowa

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    A couple of thoughts. First, major tearout (similar to what you show) can be fixed with very light shear cuts. Even the wettest wood can be turned smooth with careful tool presentation.

    As far as the warping goes...forget it. When you turn green wood, you have one chance...and only one...to turn it round. Once you turn it, and move on to another part of the bowl, all bets are off, and it will warp and change shape within minutes.
     
  3. Duane A Ross Jr

    Duane A Ross Jr

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    What I want to know is why it is tearing like that in the first place. When it was green it didn't. When it was dry it does....
     
  4. Joe Greiner

    Joe Greiner

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    When it's wet, the fibers are more flexible, and can bend enough to be sliced off cleanly.

    When it's dry, they're brittle, and snap off.

    I think.
     
  5. MichaelMouse

    MichaelMouse

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    Looks like you're cutting with the edge broad into the rotation instead of cutting narrowly across. You can't help but lift across a broad area when you do. When the wood was wet the fiber would refill the gaps as it flopped back into them, reexpanded from the crush and sucked water from the wet interior.

    http://i35.photobucket.com/albums/d160/GoodOnesGone/Frame-From-MVI_1017.jpg Shows cutting across the grain and what surface is left even with a fairly aggressive level of stock removal to re-true this dry birch.
     
  6. john lucas

    john lucas

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    Are you scraping or cutting. Scraping the wood will often give tearout on end grain portions of the wood. For whatever reason it doesn't do it as bad on green wood. Probably a combination of the water acting as lubricant and the wood being more flexible.
     
  7. robo hippy

    robo hippy

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    Welcome to the world of tear out. When turning face plate work, or flat grain (as opposed to end grain which is more like sharpening a pencil) you are cutting down hill (with the grain) for 1/4 of a revolution, then uphill for 1/4, then down hill, and again back to the beginning and down hill. There is usually the same tear out pattern 180 degrees away from the tear out you are showing. When cutting against the grain, the cuts tend to be rougher, and show tear out. Tear out tends to be worse in dry wood than in green wood. Woods that are punky or soft will tear out more than good solid wood. Some woods will tear out no matter what you do. Figured wood will tend to tear out more than straight grained woods. It is manageable.

    First, you need sharp tools, and fresh off the grinder.

    Second, you need very light cuts when you are trying to get a finished surface.

    Third, a shear angle with the tool more on its side will cut cleaner than a scraping cut. With a swept back gouge, you drop your handle, and do a very light pull cut without rubbing the bevel. Scrapers can clean it up fine, if it is held at a 45 or so degree angle, and not flat on the tool rest. Use a round nose, or inside (swept back to the left) and work on the lower part of the scraper, not above the center line of the tool.

    Also, when the wood is really bad, you can wet it with water or finish. Let it soak in a bit, then very gently make several very light passes to cut away the wet wood. In extreme cases, you may have to wet it a couple of times.

    robo hippy
     
  8. KellyDunn

    KellyDunn

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    In looking at the photo I see no evidence of any kind of shearing cut. More of a scrape. If you are working with green wood you know is going to move alot perhaps you should consider going with the flow and doing it green and letting go to town. Do the outside and sand it. Put a coat of say poly or varnish on it. Let sit a couple minutes and wipe dry. This will keep the moisture from escaping so fast to let you do the inside. Do the inside and sand. Then finish off your base. Or you do texture on both surfaces. Lots of choices but a super warped piece can be way cool.
     
  9. Duane A Ross Jr

    Duane A Ross Jr

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    What I am guessing is that my tools are dull. All I used was a bowl gouge to shape the outside. When I first started cutting after it was dry, all that came off was like sawdust. Is this not just a case of a dull tool?
     
  10. MichaelMouse

    MichaelMouse

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    A dull tool will mess up wet wood more than dry. It'll chatter, clatter and burnish, not tear dry wood. Once again, you appear to have had the nose of the gouge up trying to cut with the nose instead of the wing.

    http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=Outside.mp4

    This starts with a "bowl" gouge and ends with a broad gouge. In both cases, the objective is to have the edge at maximum depth of cut tangent to the surface, so it lifts almost nothing. The cut is made across, not up into the long grain of the wood. The shaving produced is smooth at the leading, and raggedly thin at the trailing edge. Resistance to the cut is nearly nil.

    http://i35.photobucket.com/albums/d160/GoodOnesGone/W-ShavingsDemo.jpg
     
  11. Gretch Flo

    Gretch Flo

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    jigsaw puzzle

    Michael-that seciond site with the shavings would make a great jigsaw puzzle. Nice colors and artistic.!!!!:DGretch
     
  12. barbsiddiqui

    barbsiddiqui

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    Great video, MM.. interesting to hear the sounds when cutting. That high whine always makes me feel like I'm doing something wrong when it happens.
     
  13. captjim

    captjim

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    Duane, There is an AAW chapter in Glen Allen, MS. The best way to improve your skills is to attend the meetings. I suspect there is a mentor or two that will be willing to spend some time with you. You can't beat the price.
     
  14. Dave F.

    Dave F.

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    tear out

    Just last night I was watching "The Ellsworth Signature Gauge" and he discusses and shows a fix for this problem.

    Get yourself a copy and watch it over and over. So much to learn.

    Dave F.
     

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