The Forestry Forum

General Forestry => Drying and Processing => Topic started by: Pclem on January 10, 2019, 07:34:36 PM

Title: How long to kiln dry white pine slabs
Post by: Pclem on January 10, 2019, 07:34:36 PM
I have a bunch of 2.5-4" thick white pine slabs we cut 10 years ago. they've been in a roofed drying shed since. (stickered). Pulled them out today, and look pretty good. I'm gonna make some end tables/coffee tables etc. Should I still kiln dry them even after air drying that long? I can put them in my old container firewood kiln. How long if so? I hear of 160 degrees to set the pitch, which I can obtain. Just heat them to 160 for a while? Ya, I'm pretty green. Only been drying firewood ;D
Title: Re: How long to kiln dry white pine slabs
Post by: Ianab on January 11, 2019, 02:42:02 AM
Got a moisture meter? Even a cheap one will give you some idea of what's going on. 

Issue is the wood has been outside, and exposed to conditions where it's only dried to maybe 12%? (Depends where you live). If you make furniture, and it comes into a centrally heated house it might have to dry out to ~6% in the winter. This means it's going to move a bit. Now as long as you design your piece to allow for that movement, which you should anyway, it won't self destruct. 

Also, pine is more forgiving, it shrinks less than most hardwoods, and is less prone to splitting, 

I'd suggest you throw the wood in there, crank up the heat for 24 hours to set the pitch and kill any bugs, then check the moisture level next day. If it's down to something sensible, under 10%, it's probably OK. As long as it's well air dry it will be hard to mess it up at this stage. 
Title: Re: How long to kiln dry white pine slabs
Post by: Southside on January 11, 2019, 08:19:22 AM
My experience with pine is you really don't want it any drier than 12% at 10% it starts to act up when milling it. I have had some around 7% and it was a nightmare to deal with. 
Title: Re: How long to kiln dry white pine slabs
Post by: K-Guy on January 11, 2019, 08:40:13 AM
Hi Pclem
I would give it 2 or 3 days at 160F to set the pitch due to the thickness of the wood. Southside is right about the moisture content but you could dry more after it's milled if you want.
Title: Re: How long to kiln dry white pine slabs
Post by: Pclem on January 11, 2019, 09:13:13 AM
Do you just check the moisture on the surface? I have a good delmhorst moisture meter with long and short probes. I've only used the long ones (1") for firewood. Also, "setting the pitch", is that just heating it up enough so it doesn't seep out later?
Title: Re: How long to kiln dry white pine slabs
Post by: Pclem on January 11, 2019, 09:17:29 AM
My experience with pine is you really don't want it any drier than 12% at 10% it starts to act up when milling it. I have had some around 7% and it was a nightmare to deal with.
What do you mean by "act up"?
Title: Re: How long to kiln dry white pine slabs
Post by: Southside on January 11, 2019, 09:34:35 AM
It will tear out, chunk out, sliver, splinter, knots fall apart, and cause issues with milling. It becomes quite brittle at that MC so tongues will break off if you are making T+G, shiplap, etc. 
Title: Re: How long to kiln dry white pine slabs
Post by: K-Guy on January 11, 2019, 10:00:22 AM
To set the pitch, you want to "cook" it for a bit to remove some of the moisture and make sure it sets up good.