Grain Challanges

Discussion in 'Newbie' started by Regis Galbach, Jul 30, 2017.

  1. Regis Galbach

    Regis Galbach

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    I bought a beautiful maple slap 8"x11"x1.75". It had a couple epoxied holes but, I cut an almost 8" circle. It cut beautifully but, has some difficult grains to finish.
    I first put sanding sealer on it and was shocked with the streaks. I pretty much stripped that and tried a friction finish. Drastic streaks.

    Now, I've not sure if I should just leave as is or is there something that I should try.
    1st shows sanding sealer. 2nd friction finish (BLO, Shellac, & DNA). 3rd is back and filled area.
    BTW, those are not tares where it "may " look like it. Very smooth finish at 400.
    Appreciate any tips for this or the next one I come across.
    Regis

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  2. John Torchick

    John Torchick

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    Can't help as I'm still in the learning stage of turning and all involved therein. I do like the piece you have turned and love the grain!
     
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  3. Owen Lowe

    Owen Lowe

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    That really, really looks like tear-out…

    The streaking may be “bruising” of the fibers. When the tool's heal contacts the surface and compresses the fibers it hinders finish absorption. About the only fix is to make light cuts to get below the compressed areas. I suppose you could try soaking the bowl in very hot water to try to get the fibers to swell and then rework the finishing passes once it is thoroughly dry.
     
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  4. Regis Galbach

    Regis Galbach

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    After the sanding sealer looked so bad, I went over the entire piece with a sharp scraper. Then sanded 120, 220, 320, 400 (lathe running about 150rpm and power sanding). Also, as I rotate those "glistening" areas change depending on light direction.

    Thanks,
    Regis
     
  5. Gerald Lawrence

    Gerald Lawrence

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    This is just a guess but may be the beginning of spault, or just say that is the way it grew. The grain changing directions will change the way light reflects but usually not cause those straight lines of color variance.
    To tell the truth I think it looked best in the first pic.
     
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  6. Bill Boehme

    Bill Boehme Administrator Staff Member

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    That's known as chatoyance, a very desirable characteristic. My favorite finish on highly figured maple is clear high gloss lacquer, but the surface must first be finished glass smooth or else imperfections will be very noticeable. I also like to dye figured maple to accentuate the chatoyance.
     
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  7. hockenbery

    hockenbery AAW Advisor Staff Member

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    This is a nice looking piece.
    Getting a smooth tool surface on soft maple is a challenge.
    Getting a smooth surface of highly figured soft woodmis doubly challenging as some grains gomuomwhille others go down making some grains cut the wrong way.

    I see a couple of lines. In the inside wall.
    This could be the heel rubbing. Grinding off the heel of the gouge helps eliminate this.
    Could also be the remnants of minor tearout from losing the bevel as you make the tight curve.
    Fibers tear below the surface and it takes a lot of sanding to get to below where the fibers tear.
    Grinding the heel off the bevel helps keep the bevel riding in tight turn.

    Heavy cut cuts produce more tearout than light ones. Lots of light cuts as you near the desired surface

    Avoiding the tight turn in design will help too.

    Lots of torn fibers in the grooves in the rim. These are impossible to sand and especially difficult to cut cleanly in soft wood. Might use a tool an do lines instead of grooves in the soft woods.
    I tend to avoid grooves and beads and such on really busy grain. I save them for the uninteresting wood that need something.

    It looks like some tearout on the the outide. Could be from scraping( soft woods don't scrape well), too big of a cut with the gouge, coming off the bevel, or cutting the wrong direction. The outside needs to be cut from rim to foot.. sharpen feroenthe finish cut then light cuts, bevel riding( floating over the surface).

    Finally a soft finish will show defects less than a glossy.
    Glossy will show the figure better....
     
    Last edited: Jul 31, 2017
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  8. odie

    odie

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    This is an important point Al makes. Many light cuts will generally produce a better, cleaner cut surface than a heavy cut. (Considering everything else is done to the best advantage! :p) I suspect many turners get a little anxious to make progress, and take heavy cuts.......but, in reality......heavy cuts often create more work than if he'd just taken his time in the first place! :D

    -----odie-----


    View: https://youtu.be/0ppaiQ6mhbE
     
  9. Regis Galbach

    Regis Galbach

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    Well, you all have convinced me. Glad that it is still mounted on the lathe. I'll take another " cut " at it this morning .
    Thanks
     
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  10. Regis Galbach

    Regis Galbach

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    I scraped again with light as I could (after honing scraper). Then power sanded 60, 120, 220, & 320 and this is where it is now, with no finish. I have enough thickness to go in and actually 1/16" - 1/8" deeper and sand again but, it appears that these streaks go through to the outside.
    Thoughts?
    Thanks,
    Regis



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  11. Regis Galbach

    Regis Galbach

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    I scrapped/cut a little deeper. Then power sanded in forward and reverse (on lathe) at each grit (suggested by friend). No change. Forward and reverse sanding is new to me and I like it. But, didn't solve the streaking. I'm going to take it to TAW meeting tomorrow for some guys to put their hands on it and perhaps figure something out.
    Otherwise I have a beautiful and very interesting bowl.

    Thanks
     
  12. hockenbery

    hockenbery AAW Advisor Staff Member

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    You are getting close. Practice, practice, practice.
    A smooth surface from the gouge is the key then sand with 220 and 320 maybe a few spots with 180. Plan on the next bowl being much better from the gouge. With solid technique the more you turn the better the surfaces get.

    You might be interested in video of a demo where I finish turn a dried bowl from sycamore, a soft wood that cuts similar to the soft maples.

    In truing the bowl I don’t take big cuts because big cuts might create tearout.
    The finish cuts are progressively lighter cuts.

    At 12:50 I start the finish cut on the outside with all the cuts going foot to rim.
    At the 20.20 minute mark I begin establishing the wall thickness and turn the rim
    At 24:30 I begin the inside finish cut on the top of the wall. I use a small gouge for the first 2 inches.
    The small gouge gets a little bit sharper and takes a lighter cut. This one has a Michelson grind.
    2" is about its limit before it starts to vibrate and make a bad surface.

    At the 27 minute mark I show and use a gouge with the heel ground off. This is my finish tool for the rest of the inside. No sharp heel to bruise the wood. Short bevel has less bevel drag.
    When I only had one gouge it had the heel ground off.

    Mounting and turning a dried bowl -
    View: http://www.youtube.com/watch?v=sCZWsHB4vlM
     
    Last edited: Jul 31, 2017
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  13. Owen Lowe

    Owen Lowe

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    Hey Regis,
    On the picture of the reworked surface, can you draw circles or arrows for what streaking you are concerned with? Are you talking about the light colored banding from the center-out at 6:00-8:00? If so, that is the natural grain of the maple when you have burl areas. You probably already know this: Marks that do not appear in concentric rings or regular repeating swirls are most likely natural to the piece of wood; anything concentric or a regular repeating pattern is likely caused by the human.

    The rim at 6:00 looks like it has a touch of torn grain but much less than in your first posting.
     
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  14. Regis Galbach

    Regis Galbach

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    Owen,
    Yes, those light areas "like" streaks (6-8 o'clock & elsewhere))are what I'm talking about. I too thought than any tool marks would be would appear as rings, even if not all the way around. I've seen grain pattern similar to what is at 6:30 but, never anything like at 3 & 8:30 o'clock.
    I'm putting a full finish on it BUT leaving the tenon so when I take it to TAW meeting tomorrow it will be possible to work on it some more.
    That bit of tearing at 6 is now gone.
    I keep liking this piece more and more. I was going to fill the groves with bright red but, am now going to leave as is.

    Thank you,
    Regis
     
  15. Owen Lowe

    Owen Lowe

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    Check out the attached pics from the google. All three show the commonly seen streaking, banding, whatever, you see in burled and figured maple.
    Maple1.jpeg Maple2.jpg Maple3.jpg
     
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  16. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Here is an example of dyeing to enhance the chatoyance (streaking). I have paid some high prices for maple with this degree of chatoyance.

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    Here is another one from a number of years ago that was my first dyed rim platter.

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  17. Regis Galbach

    Regis Galbach

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    Those are wonderful. I need to start keeping an eye out for blanks like this, now that I have one .
    Thanks,
    Regis
     
  18. Gerald Lawrence

    Gerald Lawrence

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    Ok then if that is caused by the curl makes more sense,but if so why is that streak so wide. Here is my curly dyed platter. Still need to work on the finish,just have other things going on. By the way Bill Jimmy Clewes says that the rim should flow toward the inside.
    IMG_2564.JPG
     
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  19. Dean Center

    Dean Center

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    Maybe I missed it, Regis, but someone needs to mention that with either tear out or spalted/punky wood, you have to CUT the wood. You'll never get a good surface with a scraper. Not even a negative rake scraper, IMHO.
     
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  20. Zach LaPerriere

    Zach LaPerriere

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    Hi Regis,

    You're making good progress! Dean makes an excellent point on cutting vs. scraping. Regarding sanding: it took me a while to run across the following sound advice that I'll repeat.

    The broad idea of sanding is that you sand to remove torn out grain at the finest practical grit. Once tear-out is removed, you sand at the next higher grit to remove those sanding marks. Each progressive grit removes the previous grit's sanding marks until you reach a point that both you and your finish will be happy.

    As for grits, you said you sanded at: 60, 120, 220, & 320. The general rule is never bump more than 50% of the grit count. So if you start at 60 you should really hit it again with 80 before going to 120. If you can start at 80 rather than 60 there is a huge difference—but you want to start with a grit that is course enough to remove all tear out. The tricky part of saying that is until you've sanded quite a few bowls you often miss tear out that only shows to the untrained eye at 180 or higher...which sadly means go back to your starting grit if you still see tear out. I used to do that regularly...

    From 120 you would ideally go to 180. 220 is pushing it a little, though plenty of very experienced turners do.

    The final thing you may or may not be doing: power sanding the more torn-out sections with the lathe off at your starting grit. In some cases it's still
     
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