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Finishing air dried walnut in Nyle l200m

Started by forrestM, April 04, 2021, 02:04:24 PM

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forrestM

hello, 

I'm finishing off some air dried black walnut in my kiln, and wonder what group you would call it if it is over 1 inch, but less than 2 inches? Mine is 6/4 and it Seems like it would be somewhere in the middle of group 2 or group 3 at that size. 

Group 2 schedule would be 120 and 90
And group 3 would be 120 and 98

Can someone tell me which I should do? And what the big difference is between those two schedules?

Thanks,
Forrest


K-Guy


Generally you would go with the safer schedule for thicker wood but if your moisture content is below 25%, it doesn't really matter as you can't cause defects at that point and you will only get a small amount of moisture.
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

scsmith42

Forrest, your kiln schedules are correlated to the MC% of the lumber, along with species and thickness.

The term "air dried" is fairly generic. To determine the proper setting you really need to start with the mc% of the lumber.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

forrestM

Sorry I did not give more context. The schedules I provided were from the Nyle book, for taking group 2 or 3 from 25 percent to final. My wood is air dried as good as it gets at 12-13 percent.  so I'm really just looking for the last squeeze. 

Of the 2 schedules, is 120 and 98 considered safer than 120 and 90, or vice versa?

Thanks!

K-Guy

Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

forrestM

I started the kiln yesterday morning with group 3, 120 dB and 98 wb 

By the end of the day I was up to 118 dB, and this morning when I checked on things I had gotten to 120 dB, but only 96 wb. 

So the compressor hasn't yet come on, that I can tell. 

In a situation like this, do you simply lower the wb until it comes on? Or keep raising the dry bulb to force the wet bulb up?

Does the current situation seem typical for air dried wood, and what's happening is that there is not enough moisture coming out to raise the wet bulb?

THanks!

K-Guy


You lower the WB but remember on startup the kiln temp isn't necessarily the wood temperature, so it may not be releasing as much moisture yet. It comes down to your judgement.
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

RussMaGuss

@K-Guy  So it's safe to lower the WB temperature towards the end of a kiln cycle to speed up drying? What MC level would it be ok to tinker with? With the white oak I dried a month or so ago, the WB was hard-pressed to get above 98. If it was at say, 88, should I have set it to 85? I don't remember anything in the manual talking about lowering the WB below the set points. Thanks for any info. It seems like if that is allowed, it would really expedite my drying since I try to air dry to 20-25% before the kiln

K-Guy

@RussMaGuss 

You can drop it after you are below 25% but it will not speed up your drying. The problem is the oak not the kiln. Our final setting is for efficiency in power consumption and drying but will not change your drying time.
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

YellowHammer

You can lower the WB set point as low as you want, down to 75F, but the issue is that as the wood gets dryer, it gives up its moisture less readily, and as long as you don't exceed the species and thickness maximum allowable drying rate, then you are OK, no matter what the settings.  

Typically, I won't go below 120/95, because going lower just runs the compressor for no reason.  

If the WB doesn't come up, it just means the wood isn't giving up its moisture.  So the chamber air is dry and there's no use running the compressor.  
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

RussMaGuss

Ok got it, so it's just a waiting game at that point no matter what. Thanks guys! 

123maxbars

Quote from: YellowHammer on April 12, 2021, 08:44:07 AM
You can lower the WB set point as low as you want, down to 75F, but the issue is that as the wood gets dryer, it gives up its moisture less readily, and as long as you don't exceed the species and thickness maximum allowable drying rate, then you are OK, no matter what the settings.  

Typically, I won't go below 120/95, because going lower just runs the compressor for no reason.  

If the WB doesn't come up, it just means the wood isn't giving up its moisture.  So the chamber air is dry and there's no use running the compressor.  
Robert there you go making perfect sense again,  ;D
Sawyer/Woodworker/Timber Harvester
Woodmizer LT70 Super Wide, Nyle L53 and 200 kiln, too many other machines to list.
outofthewoods
Youtube page
Out of the

K-Guy

Quote from: 123maxbars on April 15, 2021, 09:51:55 PMRobert there you go making perfect sense again,


Even a broken clock is right twice a day!! :D
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

YellowHammer

I was thinking more of me being a blind squirrel occasionally finding a nut, but either way....
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

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