wet maple slabs

[xlogger]

I cut some 9/4 live edge spalted maple slabs a month ago and they where on fans for the first 3 weeks. They showed 33% MC a few days ago. I'd like to put them in kiln, would I be better to wait or have any of you had much luck putting them in this early. As of now I don't need the kiln for anything else. Below is a picture of some Ambrosia Maple I cut yesterday, they where put under the fans with lots of weigh on them.

 

[GeneWengert-WoodDoc]

This beautiful maple is actually a result of the Columbian timber beetle and this happens in the living tree.  The tree, when alive, detects the presence of this beetle and is able to react when alive and form heartwood pockets to encapsulate the intruder...the tree does not have antibodies, so this is its defense mechanism.  Some people call this heartwood as pathological heartwood rather than normal heartwood.  Once a tree is cut down, the cells can no longer form heartwood, as the cells are mostly dead.

Note that 33% MC with an electric pin meter is really anywhere,as high as 45% MC, as the meters do not work accurately above 28% MC.  The wood can certainly go into a kiln with proper kiln conditions maintained.  One key area is the start up conditions.  If the lumber has been exposed to an average of 65% RH in air drying, which is common in much of the USA, then do not start the kiln at a humidity higher than 65% RH, even if the schedule asks for higher.  This is true for all species.

[Den Socling]

"encapsulate the intruder"
That's very interesting!

[WLC]

WOW!!  Those are beautiful! 

[xlogger]

So if I say it Ambrosia Maple I'm wrong? :-\

[bkaimwood]

No, xlogger, you are fine with ambrosia maple. The older school terminology was wormy maple, despite the figuring not being made by worms. I forget who, but someone recently posted a thread here about drying or sawing defects, and it involved maple...and had a lot of good info in it. I have sawn and dried ALOT of maple in the past couple years...and have learned a lot too!!! When sawing dimensional lumber, always be watching for even the slightest stress, react accordingly immediately, keep the pith centered, and so on. When sawing slabs, it's a whole different ball game....mostly because, well, you are slabbing, and not sawing stress out of two sides of your lumber...the live edge sides. So that log better be straight. Every maple  log I have slabbed that wasn't straight, has twisted...doesn't matter which face I've started with, I've tried both. The only exception has been spalted material. As with a lot of spalted logs, laying and softening or spalting seems to "work" this stress out. Maybe I just have bad luck, but I've slabbed and noticed this pattern over dozens and dozens of log sets. Never mattered if or for how long they were air dried.
Anyway, xlogger, it looks like you are well ahead of the game...that log looks like it was straight and the slabs are beautiful. I wouldn't hesitate to put them in the kiln, just run them slow...1.5-2 percent max MC drop per day.

[Den Socling]

I always wince when I see those drying rates. Our vac kilns can remove 2 or 3% per hour! Running a conventional kiln would drive me nuts.  :D

[xlogger]

Well Den if you where not so far away I'd love to put them in your kiln ;D

[GeneWengert-WoodDoc]

One might argue that since this is not caused by an ambrosia beetle, then it should not be called ambrosia maple.  In fact, this is much nicer than ambrosia beetle wood.

From DRYING HARDWOOD LUMBER: The maximum safe drying rate for 8/4 hard maple is 2.6% per day.  Soft maple is faster... 5.5%.

[bkaimwood]

One might argue that since this is not caused by an ambrosia beetle, then it should not be called ambrosia maple.  In fact, this is much nicer than ambrosia beetle wood.

From DRYING HARDWOOD LUMBER: The maximum safe drying rate for 8/4 hard maple is 2.6% per day.  Soft maple is faster... 5.5%.

No arguments here, Gene. Facts are facts. Jus' sayin' everyone around here calls it wormy maple or ambrosia maple, technically correct or not.
     I remembered the basic title for the thread I previously referred to...drying or sawing dillema... check it out.
      Maximum drying rates as listed by Gene are undoubtedly correct and accurate, because, well, Gene wrote the book on drying hardwood lumber!!!!!  Although slabs aren't a completely different ballgame, they don't always follow the rules to a "T".  Mostly because of sheer width. For instance, any given load may have a variety of widths boards in the load...for example, let's say 4-9 inches....of course, it may be more or less. Common sense would tell you a 30" wide slab of wood 2 1/2" thick will take longer to dry than a 5" wide board. It is also a higher risk for wet spots or uneven drying, just by nature. Run them like a standard load of dimensional lumber and you will increase your risk of loss.
     Den...with the amount of water you can remove from wood an hour, you should set up a hydropower plant!!!! Jus' for some side beer money!!

[Den Socling]

Baseball bat kilns collect 100's of gallons of water from Sugar Maple. Unfortunately, it cost more to extract the sugar than it is worth. We were drying something in New Zealand one time. I don't remember the species but the water that came out smelled like perfume. No hydro power but, over the years, I have thought that there should be something done with some of this water. It is all collected in a stainless steel tank. 

[Den Socling]

Again, I apologize for plugging our kilns but a 2" wide board can lay next to a 40" wide slab and they will dry the same. Look at this quote from a customer.
"The experiments of drying various species and thicknesses has gone very well. The last load had such a mix of things to be sure I ran a slow ramp. 2" maple slabs, 1" twisted and warped Koa slabs with large crotch sections, 1" fir slabs (with no pitch problems) and fir 4"x4"x8' boards, even some spruce 1" and 1.5" blocks mixed in to shim areas of piles that were mixed thicknesses. Everything turned out great, most amazing was the Koa, color unharmed and flat! Hard to believe if anyone had seen how warped they were going in they would not believe that they were the same boards!".

[GeneWengert-WoodDoc]

Width of lumber does affect drying due to the surface area compared to volume.  So a 6" wide 8/4 piece has 16" of circumference, while a piece twice as wide has 28", or 12% less surface area.  However, the edges usually provide very little contribution to drying, so the main factor for a five or thirty inch width is the face area to volume, which is the same for both, so they both dry the same, from a practical viewpoint, as Den noted.

I have seen squares spaced about 1/2" apart from each other, and this does indeed increase drying speed by over 50% compared to tightly stacked squares without this spacing.  This faster drying can cause defects with oak squares and some other species.

[Den Socling]

True if you are operating a conventional kiln but not true with our vac kilns.