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walnut tabletop cut

Started by wraylow, January 07, 2017, 05:55:29 PM

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wraylow

I just cut a 32"x3" tabletop from a walnut stump. How can I keep it from cracking during  Air drying. ?
numerous stihls , massey ferguson mf35  kubota L4701h

Den Socling


low_48

You can't, they all crack. Maybe a little, maybe a lot!

Den Socling

That's basically true because wood shrinks roughly twice as much tangentially (following the rings) as it does radially (between pith and bark). Perfectly round pieces are the most likely to crack. I have posted these pictures before but they show that some cookies can be dried without major cracks.


 


 

wraylow

Thanks Guys for the comments.  I am going to wrap  the edge in shrink wrap with the ends covered with cardboard  and let it set about a year.
numerous stihls , massey ferguson mf35  kubota L4701h

ScottCC

A fella once told me an inch per year minimum for air drying to give you the best chance for what ever that piece is capable of?
Necessity is the mother of invention.  Poverty is its big brother.  WM mp100, WM eg100, WM sp4000 chip extractor,  WM 260 molder on order ,WM electric  lt15 wide with extra track, 71 Oliver allterrain forklift, 26' flat bed trailer, road legal log arch, homemade kiln, AutoCAD lt15

Den Socling

That "inch per year" thing has been spread around and around for years. Some species vary so much from other species that the saying becomes meaningless.

WDH

The 1" rule of thumb is a poor one.  Plus a cookie will dry much faster than a board.  Much faster. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

ScottCC

Thanks, I never gave it much thought.   That's my something new today.
Necessity is the mother of invention.  Poverty is its big brother.  WM mp100, WM eg100, WM sp4000 chip extractor,  WM 260 molder on order ,WM electric  lt15 wide with extra track, 71 Oliver allterrain forklift, 26' flat bed trailer, road legal log arch, homemade kiln, AutoCAD lt15

WDH

In some places, the year per 1" to air dry might be right depending on when the wood was stacked, i.e. in late fall early winter with ice and snow for 6 months.  Here in the South, My hardwood takes anywhere from 90 days (for maple and yellow poplar) to 120 days (walnut), to 180 days (pecan, red oak) to 240 days (white oak) to air dry to about 15%.  This is for 4/4.  Once the moisture content falls below about 20%, I put the wood in the kiln to dry it below 10%, so I monitor it pretty carefully.

We get good drying conditions year round in Middle Georgia as there is normally no ice and snow, and if there is any, it is a minimal amount and lasts only a day or two.  Not the same in the frigid, cold, glaciated, Northern States north of the Mason Dixon line (AKA Yankee Country).
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

fishpharmer

Putting a ratchet strap around the outside edge of a cookie will allow you to ad pressure while it dries.  Every so often, tighten it up as it shrinks.  This prevents major splits during drying process.   It still may split after you take it off.  My success has been good.
Built my own band mill with the help of Forestry Forum. 
Lucas 618 with 50" slabber
WoodmizerLT-40 Super Hydraulic
Deere 5065E mfwd w/553 loader

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work. --Tom A. Edison

low_48

Quote from: fishpharmer on January 12, 2017, 11:20:56 AM
Putting a ratchet strap around the outside edge of a cookie will allow you to ad pressure while it dries.  Every so often, tighten it up as it shrinks.  This prevents major splits during drying process.   It still may split after you take it off.  My success has been good.
You've had good luck with walnut stumps this way?

YellowHammer

Quote from: WDH on January 10, 2017, 08:08:27 AM
The 1" rule of thumb is a poor one.  Plus a cookie will dry much faster than a board.  Much faster.
Yes.
Cookies dry in a matter of weeks, or short months.  Remember that the grain is oriented so it is all open.  I did an experiment a few years back, and among other things, I had marginal success with applying clear sanding sealer to the top of a fresh cut cookie.  The next day, I had found it would penetrate the wood and in some case would flow out the bottom before it cured.  It seemed to fill the voids and kind of glue the cookie together.  Sometimes....other times were complete failures.   
Drying cookies is very problematic.
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

fishpharmer

Low_48,  no I have not used this on walnut.  Only, cypress, oak and pine.   It did not eliminate cracks, however it seems to minimize it compared to drying without the rachet strap.

WDH, yellowhammer and Den Socling have much more knowledge and experience drying than I do.   Its just my opinion the rachet strap helps minimize splitting.  There is no reason it would not help in drying walnut cookies.
Built my own band mill with the help of Forestry Forum. 
Lucas 618 with 50" slabber
WoodmizerLT-40 Super Hydraulic
Deere 5065E mfwd w/553 loader

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work. --Tom A. Edison

GeneWengert-WoodDoc

Cracks, or one major crack, results because the tangential shrinkage in most species is twice the radial shrinkage.  So the circumference is shrinking twice as much as the radius.  Circumference = 2 x pi x r.  So, we need to increase the radial shrinkage or decrease the circumference shrinkage.  I do not see how a strap on the outside can do either of these two.

This differential is increased if we dry the outside before the interior, which can occur with a thicker cookie.  Sapwood dries much faster than heartwood.  Pieces without bark also dry faster from the edge.  If we use a coating to slow drying, the key is to use it on the outside areas and not on the central section.

If we remove the core by drilling a large hole, it is now possible for the radius to decrease, and large cracking is prevented.

The circumferential shrinkage puts tremendous pressure in the radial direction.  So, with very low density wood, the cells can collapse from this pressure in the radial direction, thereby preventing a major check.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Ljohnsaw

Quote from: GeneWengert-WoodDoc on January 13, 2017, 08:49:07 AM
If we remove the core by drilling a large hole, it is now possible for the radius to decrease, and large cracking is prevented.

Doc,

If I were to use a 4" or larger hole saw and remove the center of a cookie (say a 24" pine or cedar, 2 or 3" thick), and then replace it (trimming if necessary) when dry - what are the odds of no cracking?  I could coat the outer rings of the remaining cookie with sealer to slow them down.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

GeneWengert-WoodDoc

This is about as much reasonable that you can do.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

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