The Forestry Forum

General Forestry => Drying and Processing => Topic started by: logboy on December 15, 2014, 12:23:23 AM

Title: Drying Pine Slabs
Post by: logboy on December 15, 2014, 12:23:23 AM
I have a question for the drying gurus. Is it possible to dry 3" thick white/red pine slabs too quickly in a DH kiln? I know theres a fine line between drying properly and starting my own fungus farm. Normally I'd stack them outside to dry for the summer, but it wont be above freezing here for four more months, and I'm currently all out of pine slabs. Is my Ebac unit even going to be able to keep up with the water that needs to be removed to prevent mold initially? These things are frozen solid, too. Will the outside start to give up water and grow mold before the core is even up to a reasonable temp? Any ideas for an initial temp that wont grow mold or damage the wood?
Title: Re: Drying Pine Slabs
Post by: scsmith42 on December 15, 2014, 09:01:27 AM
JR, for slow drying species application of a fungicide on the slabs such as Premier will prevent mold/mildew buildup.

With my L200, 4/4 SYP has a daily drying rate of 15% / day.  I reduce the 4/4 recommendations by 60% for every additional inch. Thus 3" SYP would be targeted for 5.5% per day MC removal (15% x .6 = 9%; 9% x .6= 5.5%). 

My Nyle is rated for a maximum load of 4000 bd ft of 4/4 oak, which dries at a rate of 3.5% per day.  For a 5.5% load, I would reduce the capacity to 2500 - 3000 bd ft in the kiln so as to have enough compressor capacity to remove moisture quickly enough.  By running the kiln near max capacity for the amount of water to be removed, it provides an extra safety margin as you don't need to worry about drying too quickly.

If you start the load at a temp greater than 110F, usually mold will not develop.

I'm not sure how white/red pine dries compared to SYP.

Hope this helps.
Title: Re: Drying Pine Slabs
Post by: red oaks lumber on December 15, 2014, 05:58:29 PM
when i dry pine slabs,its wide open, hammer the heat to it about 120 deg. running the compressor 100% .do this until you start seeing small surface cracks, at that time remove from the kiln and let them rest for a week, then put them back in. repeat 2 more times.during the last cycle crank the heat to 135 deg. until they have reached your target moisture. white pine will dry alot slower than red pine, bear in mind there are 2 types of slabs green and cracked :)
Title: Re: Drying Pine Slabs
Post by: GeneWengert-WoodDoc on December 15, 2014, 07:33:48 PM
If you only put a few pieces in the kiln, you might indeed dry too quickly, but a substantial load would be difficult to dry too fast.  A huge load would probably dry too slowly and develop stain or mold.
Title: Re: Drying Pine Slabs
Post by: logboy on December 15, 2014, 07:59:13 PM
You'll have to narrow it down a bit for me, Gene. I'll have roughly 3000 bdft of 3" thick slabs when I turn the key. Any idea how an Ebac LD3000 will perform with this load?
Title: Re: Drying Pine Slabs
Post by: GeneWengert-WoodDoc on December 16, 2014, 07:30:44 AM
A general guideline for your species and thickness is to use no less than 1-1/2 hp per 1000 BF, and for thinner use 2 hp per 1000. 


So, if the 3000 has 3 hp, the 3000 BF of oak is fine, but for pine, only 1500 bf.
Title: Re: Drying Pine Slabs
Post by: red oaks lumber on December 16, 2014, 11:37:25 AM
i wouldn't try drying that many slabs at the same time, you'll have mold and bluestain issues and there is a good chance of drying the surface to much.
at the very least don't mix red and white pine together, the white drys alot slower. i usally dry maybe 5 at a time ,i lean them up against a stack of 1" in the kiln that way i can control the drying of the slabs.turning them over and taking them out of the kiln one by one gives you complete control  of the slabs