Walnut drying question

[Crossroads]

Just wondering if anyone has tried drying walnut in reverse? What I mean is to put it in the kiln, fans off, dehumidifier off, heat on. Bring it up to a given temperature and let it sit for a couple days and then turn on the dehumidifier and just enough fan to circulate the air. Maybe a waste of time, but I was just trying to think outside the box.....

[scsmith42]

If you heat it too much while it's above 25% MC you'll run a high risk of internal checking.

[beenthere]

Crossroads
Which "walnut" are you asking about? There are differences. See this link

https://gobywalnut.com/blogs/articles/a-brief-history-of-oregon-black-walnut

Likely to do what you suggest the important control would be the RH in the kiln. And the drying schedule would be fairly long in days or maybe weeks. 

In the "old" days, Eastern black walnut thick gun stock blanks were dried in kilns for 7 months to avoid internal checking referred to as honeycomb defect. Caused by surface drying before internal drying.. 

[Crossroads]

I have some black walnut that I'm going to be drying in the near future. After my last experience with walnut, I was wondering if changing the process would help. After talking with customsawyer, I don't have the heat available for the temps he uses. 

[firefighter ontheside]

Why were you thinking of doing this?  What was your last experience with walnut?  In my experience walnut behaves very well, especially if air dried first.  I would be worried that heating first would cause issues with color and the checking that has already been mentioned.

[Crossroads]

https://forestryforum.com/board/index.php?topic=121464.0

Not sure if I did the link right, but this was my my last experience with walnut. Granted there is some information missing like the MC coming out of the kiln, but the consensus seems to be that walnut like to stall. 

How long are you air drying before you put in the kiln? I'm not going to have much time for air drying on this batch as I'll be milling the log into 2 1/4" slabs today and will probably get it in the kiln next weekend when I return from a mobile job. 

[firefighter ontheside]

Ok, I do remember that.  I usually air dry for a year or so.  The last run of my kiln I had a similar problem with 4/4 that I had only air dried for about 6 months.  It stopped at about 10% for a while.  I kept it going to get it down to 8% and then sanitized which brought it down a little more.  A week of air drying 9/4 isn''t gonna do much.

[Crossroads]

Yeah, especially this time of year. The humidity is 53% right now and was 87% yesterday. I didn't get it cut today anyway, I was busy with other stuff this morning and spent the afternoon getting ready for week of mobile work over 500 miles away. 

[customsawyer]

Keep in mind I only use those temps when it stalls or during sterilization.

[K-Guy]

I'm not going to have much time for air drying on this batch as I'll be milling the log into 2 1/4" slabs today and will probably get it in the kiln next weekend when I return from a mobile job.

From green that would be around a 8-10 week drying cycle at that thickness.

[Crossroads]

Ah, and that drying schedule is with a real kiln, not my red neck setup. 

[cabindoc]

Ah, and that drying schedule is with a real kiln, not my red neck setup.

Did you start the drying run on the Walnut?  I'm learning from your mistakes, so do tell.   :D  I just started a load of Eastern Black Walnut after air drying for about a year.  MC to start with was about 25% on average using a Delmhorst 2" pin meter.  First 24 hours I got 5 gallons from 500BF of 2"- 2 1/2" slabs.  

[Crossroads]

Sorry for the slow response, I haven't been on this section of the forum for a while. I did leave the wood in the kiln with the dehumidifier and the fan running, I've been pretty busy with some other projects and haven't had time to check the MC. I did however open the front last week long enough to get my floor jack out and noticed the straps were loose, so I tightened them up. Also, there is still some water accumulating in the bucket from the dehumidifier. I may have some time this week to test it and see where the MC is. 

[Crossroads]

Well I finally checked on the walnut in the kiln yesterday and it is at 10-12%   And seems to have behaved well with minimal cracking and warping. Now I just need to find someone who wants it more than I do 😁