Kyle, Jeff or any other sawyer....Would be great to add general information about proper procedures of air drying any species that we might buy from you that is wet (green)) so we want ruin it. Or point us in the direction of finding this info. I have a small supply of red oak and walnut and was wondering the appropriate way to air dry. Thanks for your consideration.
Wayne, there are many ways to air dry lumber but let me give it my best shot. Others please feel free to comment / correct what I'm about to write.
I'll use black walnut for an example... Only because it's one of the easier ones to dry...
1st is to know some characteristics of the lumber you want to air dry. Understand the max moisture content loss per day, it depends on the species and thickness. if you know the MMCLPD (max moisture content loss per day) for say 4/4 then 8/4 would be 1/2 of that 12/4 would be half of 8/4 again 12/4 would be 1/2 of 16/4. MMCLPD of 4/4 black walnut is right around 7%, so 8/4 would be around 3.5%, 12/4 would be around 1.75% and around 16/4 would be less than 1% (.875). If you exceed the MMCLPD, you can almost be assured there will be splitting and face checking. Because the wood is drying too fast.
2nd is to know if the wood your wanting to air dry is prone to bug infestation. Black Walnut (heart wood) is not - it's it's own natural insecticide. Black walnut is pretty toxic to bugs and humans. As a side note saw enough of it and you'll know what I mean :roll:. One of the big benefits to kiln drying is sterilization (bug kill) and pitch setting (soft wood) this is where the load of lumber is brought to a certain temperature and maintained for some amount of time. I don't know the exacts here (kiln dudes chime in please)
3rd is proper sticking, Sticking involves placing a row of lumber down and placing sticks (1" thick strips of wood) in between the rows spaced 12 ~ 16". Make sure you support the ends of the boards so have a row of sticks within a few inches of both ends. Here is an awesome example of some 8/4 BW that's sticked for air drying.
Make sure you keep it up off the ground and provide a (roof) for your stack, an old piece of tin works great... just about anything would work aslong as you keep the direct sunlight and weather (rain) off the wood. Strapping the pile never hurts either it'll keep some pressure on the pile and help it dry straighter. Some people use weight (lots of weight) instead of straps. Position your stack north to south in a shady to semi shady area. Most wind blows from west to east and you definitely don't want to "cook" your lumber by stacking it in too much direct sun, doing so would exceed MMCLPD easily.
4th how long to reach equilibrium? Great question, all kinda depends on the weather, right now were cooling off some, I most defiantly would not sell green hardwood lumber in the middle of the summer, especially something like oak with a 4/4 MMCLPD of 3%. But I wouldn't hesitate to sell it this time of the year (later summer early fall). Why? because the chance to exceed MMCLPD is high also in the summer months it's ideal time for bug infestation and mold growth... But this time of the year is good, less chance to exceed MMCLPD, less chance of bugs and mold growth.
Overtime properly sticked lumber will reach equilibrium with the environment it's in. best one could ever hope to achieve outdoors is around 12~15% in North Carolina. When your stack gets to that magic number it's ready to be used for outdoor projects. this could take up to one year (depending on the weather).
5th What about lumber for indoor use? think back before air conditioners, dehumidifiers and forced air heat. ok I'm not that old but you get what I'm saying. We humans like our constant temp and humidity levels and we maintain it by machines. the interior of our home demands wood to be drier than it would be outdoors. Your target is 6~10%, 8% is ideal. so how do you get your stack down that low? three ways I know... Have it polished off in a kiln, dehumidify it yourself, stack it up in the living room for up to 6 months
. Once your lumber reaches 25% or below you can "beat" on it a little more... What I used to do before I met Scott was bring the stack into the shop, re-sticker it, make a trap tent along with a dehumidifier and run the dehumidifier till my stack reached 6~8% it took several weeks to suck the moisture out of the lumber. the tarp/dehumidifier method is good for a small amount of lumber maybe upwards of 100 BF, but is not practical for much more. If your shop is climate controlled then you can bring it into your shop , point some fans on it and let it accumulate to the environment it's in could take several months.
There's probably more I'm forgetting but this is the high-level executive answer...
BTW - it's much easier, far less hassle and quicker to buy kiln dried, of course it's gonna cost more...
Thanks