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red bud burl advice

Discussion in 'Woodturning Discussion Forum' started by Karl Best, Oct 15, 2020 at 2:13 PM.

  1. Karl Best

    Karl Best

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    I was given a red bud burl that's been sitting for a couple years. I did a preliminary turning to find out what's inside. Diameter is 11". There's a bark inclusion that runs through the bottom, so my first question is whether to cut a tenon or a recess for mounting on the chuck -- which is going to be stronger? (The base that you see in the photo is about 4", and I've scribed a circle at 2 ½" which is my normal recess size. I've got a Vicmarc 120 chuck with spare 5" jaws.)

    Most of the inclusions will go all the way through once I start hollowing; that big one by the base is >1" deep. I'd rather keep the bowl natural, but am I going to have to go the resin route to keep this in one piece?

    I don't have a great deal of burl experience -- none, in fact. And I'd rather not screw this one up; the burl was given to me by an arborist friend just before he died from cancer, and I have my daughter's wedding coming up... IMG_4537.jpg
     
  2. hockenbery

    hockenbery AAW Advisor Staff Member

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    You need to be very careful with this piece. This is definitely a dangerous pieces once you start hollowing you will cut through the wood holding the pieces in opposite sides of the voids..

    No recess would be safe.

    a tenon is iffy. Consider using a glueblock on face place.

    Lyle Jamieson has a nice video on using a glue block. See below.

    There is another bad looking bark inclusion on the top half. You don’t want a flying wedge with two sharp corners.

    lyles video. Key to a good faceplate and glueblock is turning a slight concave in the wood.
    This way the rim of the glue block makes a tight fit. There is space between the surfaces for the glue bead to spread out making a larger glue surface. Also when to bring the glue block to the glue bead give it a little twist to spread out the glue.


    View: https://www.youtube.com/watch?v=y8b35iq4LTA
     
    Last edited: Oct 15, 2020 at 3:09 PM
  3. hockenbery

    hockenbery AAW Advisor Staff Member

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    This piece from what I can see is not safe to turn.
    Maybe if you added stitches or pewas across the void. Or use resin.
    You need a dependable structure holding the side of the bowl on

    Basically half the bowl will be flying around once you start hollowing.

    If it is totally solid on the occluded side tape and wires might work here to let you hollow.

    consider cutting it up for hollow ball Christmas ornaments

    B7788D76-54A5-40C0-B369-437BB5102255.jpeg e
     
    Last edited: Oct 15, 2020 at 3:17 PM
  4. Karl Best

    Karl Best

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    Thanks, Al. I'm glad that I asked the experts first. I was certainly planning on staying out of the line of fire, as Reed always suggests, but I don't want to be near a time bomb.

    Would filling the inclusions with resin make it safe(r), I should I just cut it into smaller pieces?
     
  5. hockenbery

    hockenbery AAW Advisor Staff Member

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    probably. i don’t have much experience with resin fills. There are several poster who may join in.

    The resin has to bond to solid wood which means removing a lot of the bark to expose the wood to the resin. This is tedious to do without losing the flowing curves of the voids.
    If you just put resin in the void with bark on the edges then you will have flying resin because bark has no structural value and will pull free.

    emotional and sentimental values make trying to save it worthwhile.
     
  6. Richard Coers

    Richard Coers

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    It would have to be a really thin resin to soak into the bark. No matter what you do with that, it's still a ticking bomb waiting to blow. If you insist on working it, KEEP YOUR SPEED WAY DOWN!!!!!!!
     
  7. hockenbery

    hockenbery AAW Advisor Staff Member

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    karl, do you do any hollowing? If the blank is solid wood where you have it attached to the lathe you could perhaps turn a hollow form with relative safety. Here is a 15” diameter maple burl 181AAF4C-6F75-4A74-B353-E034F79118DA.jpeg
    This piece likely would have blown up if turned as a bowl. The chuck would be at the openingand not enough wood to hold it together. Turning as a hollowform the as the voids are revealed the wood is thin toward the rim putting little stress on the holding. Also being thin and light if a piece breaking off will be less dangerous than a heavy chunk. This piece was tapped with wire to keep the tape round going across the void.
     
  8. Karl Best

    Karl Best

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    Hmm.. that's an idea. I've done a few smaller hollow forms. But while the other end is more solid it still has some cracks and inclusions that run all the way through. IMG_4539.jpg
     
  9. robo hippy

    robo hippy

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    As others have said, this is a high risk piece. I would choose a tenon for this one, and I generally prefer a recess. The expanding chuck will try to split the piece. Not sure about the glue block idea. I would turn a small tenon on it anyway to help it seat in the waste block, and then part off the bottom. After reversing, and before hollowing out the inside, I would wrap the outside in stretch film for a little extra help in holding it together. I wouldn't stretch the film really tight, more snug. If you are turning thin walled, like less than 1/4 inch, the added pressure can deform the walls. You could try super glue and saw dust or other fillers to help patch the cracks before you hollow. It is still not safe, but more safe than it is now. The problem with the super glue fill/patch is that the inside, unless dried for a couple of days can still be wet. This one looks big enough to core, maybe a couple of cores. I would want a tenon for that, and would not trust the glue joint. A titebond joint would be preferred to a super glue joint. Reason being that the titebond will take shear forces, like when you have a catch, better than the super glue. I have no clue about the resin fillers, but would think you would want it in a vacuum pot to make sure it penetrates all the way through. The pros can tell you more about that than I can... Looking forward to seeing the final piece.

    robo hippy
     
  10. hockenbery

    hockenbery AAW Advisor Staff Member

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    this side is showing too many cracks.

    I think you are best off cutting this one up, the cracks run all though it.
    Boxes, ornament balls, pens,
    Small hollow form ( maybe 3” - 4” spherical)
     
  11. Karl Best

    Karl Best

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    Thanks, Al. With all those cracks I think that's probably the best course.
     
  12. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Resin would mostly be bonded to nothing more substantial than weak crumbly bark which is only slightly better than being bonded to air.

    The well known woodturner, John Jordan, is often quoted as saying, "life is too short to turn crappy wood". The unspoken implication being that there's no reason to make it even shorter.

    The only good thing about using a mortise (recess) on this piece of wood is that it would probably have split the piece before the lathe was turned on thus saving you from serious injury. A tenon probably wouldn't have lasted much longer.

    The aptly named "line of fire"is the most dangerous place to be while turning, but it's a mistake to believe that you're safe by just standing slightly outside that most dangerous zone. When a piece of wood separates from a spinning blank it's unlikely to be a clean separation which means that it will probably be deflected so that it's trajectory deviates away from the idealized line of fire. Additionally, the turning tool is almost certain to be the trigger that sets a piece free from the rest of the wood. Contact with the turning tool can deflect the piece considerably away from the line of fire. Then there's the tool rest and other parts of the lathe that the piece may bounce off of and even further alter the flight path of our misguided missile. To be safe, besides staying out of the line of fire, turn sound wood, and wear PPE (face shield and respiratory protection).
     
    Tom Gall and hockenbery like this.

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