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+-- Thread: Staked table out of tree slice? (/showthread.php?tid=7324102)
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RE: Staked table out of tree slice? - overland - 10-22-2016
Looks to me that even after drying (and cracking) it's going to continue to be unstable with seasonal changes in humidity. Cracks will open and close, and even butterflies won't be able to prevent these yearly changes. I don't mind cracks and stuff--they will be part of the look, and they're the reason I suggested using staked legs--but i worry about it falling apart over time.
RE: Staked table out of tree slice? - Souperchicken - 10-22-2016
As the others have said it's not possible to prevent the cracks, unless you store it underwater.
I think one way to prevent it falling apart is to use a heavy steel band around the circumference, maybe made as a tight fit after it dries. Or make the band adjustable if you put it on before (I could see using a welded nut on one end of the strap with a bolt on the other). With the steel band you wouldn't have to worry so much about the legs splitting it.
RE: Staked table out of tree slice? - overland - 10-22-2016
I'm not trying to prevent cracks. It will crack. I'm trying to prevent it from falling apart.
RE: Staked table out of tree slice? - Steve N - 10-22-2016
Probably not near as consistent as a metal band. I tried a Jorgy band clamp and well, Mother Nature usually wins, and she did there too
I final figured there is a reason you don't see these made out of tree slices
RE: Staked table out of tree slice? - Rick L - 10-22-2016
http://www.preservation-solutions.com/wood-treatment-products/wood-treatment-product-guides/stabilizing-a-cross-cut-section-of-wood-with-pentacryl/
Look at pic number 13. No need for pressure or special equipment or steel bands. Any one can do it you follow pentacryls directions...
RE: Staked table out of tree slice? - ianab - 10-23-2016
The real problem is that wood shrinks different amounts in different directions, by a significant amount. So for a piece like in the picture, the diameter has shrunk maybe 4%, that's the radial shrinkage across the growth rings. But the Circumference or Tangential shrinkage (along the growth rings) might be more like 8%.
So you can't have a chunk of wood loose that much more circumference compared to diameter. Something has to give, and that's the typical crack that opens up. In this case it's not so much about the method, speed or uneven drying. It's the fact the woods shrinkage IS going to be uneven, and it doesn't matter how you dry it, or what you paint on it. Eventually it's going to dry out, shrink and crack.
PEG works by soaking into the wood, displacing the water and taking it's place. It remains in place, so you get very little shrinkage, and the piece has a better chance of staying intact. But it's problematic / expensive as Steve points out.
Another strategy is to accept it's going to dry out and crack. So you cut an expansion gap from the bark to the pith. Now the gap is going to be sort of straight. Then once it's finished moving you cut out a matching slice of pie from and adjoining slice and wedge it into place. Some epoxy and butterflies and you have a complete table top again. One the wood is "dry", it's not going to move much more unless it subject to extreme moisture change.
There are other things that can help. Some species have lower and more even shrinkage, some are softer and can deform a bit as they shrink. An old log that's started to spalt may also be softer. A hollow slice has a better chance of staying intact, and pieces with ingrown bark have those as natural expansion gaps.
RE: Staked table out of tree slice? - Rick L - 10-23-2016
http://www.preservation-solutions.com/product-reviews/woodworkers-journal-pentacryl/
PEG is wax so you can't put finish on it. You have to heat PEG to keep it liquid.
Pentacryl can be stained or painted. It really does work
RE: Staked table out of tree slice? - Steve N - 10-23-2016
Rick, maybe you could find a tree slice, just like the OP is talking about, and do a picture post of your Pentacryl treatment with it, and show us the results?
RE: Staked table out of tree slice? - Cdshakes - 10-24-2016
(10-22-2016, 04:00 PM)Steve N Wrote: I final figured there is a reason you don't see these made out of tree slices
oh, i thought the giant crack in it would be the adjustment for daylight savings!
RE: Staked table out of tree slice? - Souperchicken - 10-25-2016
Yep, I know you're trying to keep it from falling apart, and the steel band would do the trick- the wood could crack into a million pieces but if it's clamped up with the steel it would stay in place. I know it would change the look quite a bit but I think it could be pretty nice looking. Making it adjustable without having problems with the adjustment mechanism scratching your leg as you walk by might be a little tricky.