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8/4 with oak slabs

Started by xlogger, April 09, 2017, 07:22:56 AM

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xlogger

I've got about 400-500 bd ft of WO 8/4 slabs to put in next load for the kiln. My first drying for WO. This slabs where cut well over a year ago and top slabs show 14%. They been under shed with not much air flow. Can they be dried with 120 DB and 75 WB?
I now have some Magnolia slabs in kiln that are still not dried, for the first two days it drip about 7 gallons of water but slow down a lot (really all most stopped). Danny this are the ones I called you about last week. I cut the DH off and turned up heat yesterday, with opening the door a few times a day to let out humidity. I was thinking today dropping the temp and cutting back on the DH. Is this a bad or good idea?
Ricky
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

WDH

I would run the magnolia at 120 DB and 75 WB.  Thick slabs give up water grudgingly, but magnolia is not a difficult species like thick WO. 

If the WO is truly below 20%, you can start conservatively for the first 5 days or so, and when you run out of water, which you will, and think they are dry, they are not.  Then hit them at 120 and 75.  When you then think they are dry, they still probably are not  :).  Thick WO requires quite a bit of resolve.  To keep the DB at 120°, you will have to vent, and you will lose water vapor out of the vents so there will be much less water coming out, fooling you that you are done. 
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

Den Socling

xlogger, what kind of moisture meter are you using? I would bet that they are wetter than 14%.

xlogger

Danny I did have the magnolia at 120/75. But it stop putting out water and still in upper teens. I ran the heat up yesterday and cut it back this morning and waiting on kiln to cool down some before cutting DH back on. I'll see if I get water in bucket now.
Den its a Delmhorst J2000,
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

Den Socling

xlogger, are you using the short pins on the meter or are you going deeper with a slide hammer and insulated pins. The J2000 is a good meter but the short pins are only good for 4/4.

xlogger

Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

Den Socling

14% at the core is very surprising. If there is no error, you can't hurt the wood. From my experience, it takes a lot of energy (heat) to get White Oak to 7%.

YellowHammer

XLogger,
White oak is a battle.  Don't get in a hurry, but you will have to beat it to death to release its water.  Not sure that makes sense.....
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

xlogger

Quote from: Den Socling on April 09, 2017, 02:09:55 PM
14% at the core is very surprising. If there is no error, you can't hurt the wood. From my experience, it takes a lot of energy (heat) to get White Oak to 7%.
I"ll double check it again this week. I took two reading and got the same, both on top slab. I was just planning on getting it below 10%. Is that wrong?
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

Den Socling

You need to get the core under the fiber saturation point which is very roughly 28%. If everything is truly under 28%, the wood is not going to do the shrinking that cause checks and honeycomb.
Danny knows a lot more about DH kilns than I do but I finish WO at 150. What is your auxiliary heat? Can you get anywhere near that? When I'm at 150, I can finish WO in a couple days.

Den Socling

I would add that 120 gets the free water out of WO in my vac kilns. When I see it's gone, I ramp up to 150.

xlogger

I use my OWB only for heat. I've got it right at 150° just a little under several times for sterilization. I can turn up the temp in the Boiler some to get 150.
So Danny if I do this and I'll have to keep vents close to get that high, would you just open doors a few times a day to let out the humidity?
At first I said WO been drying over a year but probably close to 2 years.
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

WDH

On the L53, the compressor will not operate above 135 degrees, so you either have to stay below that or turn the compressor off and ramp the heat with the OWB.  You could leave the vents cracked open about 1/4 and see if you can hold temp at 150.  Opening the doors several time a day will also exhaust water vapor, but you also loose your heat. 

I can dry 9/4 slabs without doing the above, but it just takes time to coax all the water out.  On thick slabs, I would happy if they dry to below 10%.  That is close enough for me.   
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

xlogger

Quote from: WDH on April 10, 2017, 07:43:17 AM
On the L53, the compressor will not operate above 135 degrees, so you either have to stay below that or turn the compressor off and ramp the heat with the OWB.  You could leave the vents cracked open about 1/4 and see if you can hold temp at 150.  Opening the doors several time a day will also exhaust water vapor, but you also loose your heat. 

I can dry 9/4 slabs without doing the above, but it just takes time to coax all the water out.  On thick slabs, I would happy if they dry to below 10%.  That is close enough for me.
Danny by saying you don't do above, do you mean not opening vents or opening door or both? I put the slabs in yesterday and was dripping water at about a drip every 2 seconds @ 120/75. Db was around 100 when I saw the drips.
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

WDH

What I mean is that I do not run the heat to 150 degrees with the compressor off and the vents cracked open 1/4 of the way.  I keep the temp below 130° and leave the compressor running and just let it take whatever time it takes to get below 10% moisture content. 

I only run at 150° for 24 hours with vents closed when I am sterilizing the load once the final moisture content is below 10%.
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

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