Anchorseal

[YellowHammer]

Since moisture essential “boils” out of the wood on a vacuum kiln, that make sense to me.  However, end sealing is useful during the air drying steps leading to the vacuum kiln, where a different mechanism takes place for drying.

Vacuum drying cycles are known for producing exaggerating cup, and such results were published decades ago in research papers.  Strapping loads as shown in the picture constrains the ends of the stacks, but not the center, unless steel is used for the top and bottom strap bunks.  I can see the top wooden bunk curving in the photo, so that is actually encouraging cup. Also, individual straps, place down the length of a stack, doesn’t reduce twist as they are not continuously constrained, as a layer of inflexible concrete of granite would be.  

Uniformly distributed weight, and lots of it, is the surest way to not only reduce bow and curve in wood, but also straighten it, depending on its thickness and the amount of weight.   

[tyofwa]

Should I ditch the straps?  If so, what do you recommend for adding pressure to the stack?  I can build a tube frame in a 12' x 4' footprint.  Could fill that with granite / concrete / steel.  What weight target should I have?  My forklift has a 5k capacity, shoot for that?  

Thanks, appreciate your input.  

[doc henderson]

I think "more is more" to a point.  you have taken into account the limit of your equipment.  If you want to use the straps, you need to have a stack more uniform in width and use a heavy rigid board top and bottom at each strap.  did this wood have end cracks before the drying and is that why the metal straps?  if so, you may be fine with fresh sawn, air dried stuff that is solid.

[Stephen1]

I had troubles drying his wood in my kiln until I cut the painted ends off as it went in the kiln. His wood dried better and faster after that.
I believe the moisutre needs to come out the ends in the vacumm kiln. Anchor seal melts off in the heat and I find nothing on the ends when I pull the wood out of the kiln.

Hate to thread jack, but super curious about end grain sealing for wood in the iDry.  Ive been struggling to keep wood movement to a minimum.  Last load I sealed the ends of all slabs with Titebond III (all I had on hand).  Added end framing straps to reduce checking, and lowered temps.  Load looks better, but now you got me thinking I might have turned too many knobs at the same time.  
(Image hidden from quote, click to view.)


Should I avoid end sealing for kiln drying?  

I never avoid end sealing in the IDRY. I just will not appy anchorseal unless the logs or lumber are fresh cut. I find right off the sawmill and into the kiln do not need end sealling on most lumber, cherry and poplar is bad for cracking.

[YellowHammer]

I use 3,000+ lbs per stack of 800 bdft of uniformly distributed weight a nominal 4x8 pallet.  It makes a difference.  Think of a flower pressed between the pages of a book.