The Forestry Forum

General Forestry => Drying and Processing => Topic started by: grweldon on January 15, 2019, 01:52:01 PM

Title: Air drying without overhead cover
Post by: grweldon on January 15, 2019, 01:52:01 PM
I've gathered quite a pile of logs to mill but I don't have any really good method of air drying.  I have limited space with a roof.  I've seen (and done myself) people create a stickered stack out in the open and cover it with corrugated sheet metal.  I didn't have great results from this.  I've had much better luck stickering under a roof.

The problem is that I've run out of roof space.

I've seen stacks of oak stickered at a local flooring producer right out in the open.  They have tall stacks because they use forklifts and they have some sort of material at the top of the stack to keep water out of the stack, but when it rains, the board get wet, especially the outside pieces.

What do others here do?
Title: Re: Air drying without overhead cover
Post by: GeneWengert-WoodDoc on January 15, 2019, 04:27:20 PM
The use of pile covers is fairly common.  The pile cover is the same length as the lumber, but hangs out over the edges by at least one for and preferably two feet on both edges.  The main benefit is the protection of the lumber from rewetting and extreme drying from direct sunlight.  Most pile roofs do an excellent job of protecting the top five layers.  For this reason, a larger roofed shed is better in that it protects the entire pile.  You can see some pictures of pile covers in the Forest Service's AIR DRYING OF LUMBER by Rietz.

A lot of companies have a large pallet with a layer of plastic or roofing paper that is then covered with pieces of lumber.  The entire assembly is used over and over again.

Some companies use corrugated metal, but fastening it well so it does not blow away is a challenge.
Title: Re: Air drying without overhead cover
Post by: Escavader on January 15, 2019, 06:16:06 PM
The covers arent so much for keeping the wood dry,its to keep the direct sun off the top layer to avoid cupping,or degrade.We cover most of our packs with a sheet of old metal roofing before we strap it tight
Title: Re: Air drying without overhead cover
Post by: WLC on January 15, 2019, 07:39:50 PM
I stack mine up and cover the stack with roofing metal.  I make sure I have plenty of overhang on each end and the sides.
Title: Re: Air drying without overhead cover
Post by: longtime lurker on January 16, 2019, 09:04:47 PM
Wood can lose water to emc while in a pond, so a bit of rewetting from rain is neither here nor there provided adequate protection against mould and fungal attack is provided. Suns the one though... Direct sunlight on green timber is asking for trouble. And make sure your stack bases are level and have plenty ground clearance to get airflow to the bottom layers.

Other than that its fine, been millions of MMBF air dried in the open over the last couple thousand yeare
Title: Re: Air drying without overhead cover
Post by: YellowHammer on January 16, 2019, 11:34:59 PM
When I run out of space, I have a bunch of beat up pallets that I have attached roofing to.  I just put them on top of the stack when needed and stack them off to the side when not needed.
Title: Re: Air drying without overhead cover
Post by: Al_Smith on January 17, 2019, 10:16:55 AM
If you ever get a chance to tour or visit Holmes or Wayne county Ohio it's worth the trip .In the heart of Amish country and also outstanding Ohio oak you can see stack after stack of uncovered oak in the mills air drying before they are kiln dried .Much of this outstanding lumber is used for the production of furniture .Obviously  not all of it would cut fine and select so it gives rise to pallet oak and other uses .
Title: Re: Air drying without overhead cover
Post by: GeneWengert-WoodDoc on January 18, 2019, 03:39:31 PM
There are two major effects when partly dried lumber is subject to wetting from rain, melting snow or even steam spray or water spray in a kiln.

The first effect is that the MC of the surface, which is around 12% MC, increases to 30%MC instantly and tries to swell instantly, which pulls small surface checks deeper, creating interior checks, also called honeycomb.  In oak, the interior checks are large.  In woods like maple, the checks are hairline.

A second effect is that in air drying, the 12% MC surface is stronger than the wet core, so when the wet core tries to cup, the strong drier shell resists and lumber dries fairly flat.  If the shell gets wet, it is no longer as strong and so the cupping forces can "win" and cupping results, which cannot be flattened.
Title: Re: Air drying without overhead cover
Post by: moodnacreek on January 19, 2019, 08:37:49 PM
Probably have 100 M on sticks outside. The piles are 14'+ high and 4 ' wide. The covers are 5'6" wide double sided pallets with corrugated tin on top. They must be heavy to not blow off. Putting weight on them is not the way to go although I did it for years. Side ways rain and snow and powder post beetles are the problems. You can't beat drying and storing under a roof.
Title: Re: Air drying without overhead cover
Post by: grweldon on January 22, 2019, 01:15:09 PM
Thank you for all your replies.  I find them very helpful.  I guess I knew the answer when I asked... as Moodnacreek said in his reply, "You can't beat drying and storing under a roof."

I was already leaning toward roofed storage, however, I need more roof space for the tractor that's in my woodshop, and the two 4-wheelers, and the dirt bike.  I have a 16'x40' loft that were going to be useful rooms, but so far it's wide open storage space for the first round of floor space clearing in the barn.  I knew I should have made the barn bigger from the git-go...
Title: Re: Air drying without overhead cover
Post by: alan gage on January 25, 2019, 04:11:10 PM
Quote from: grweldon on January 22, 2019, 01:15:09 PM

I was already leaning toward roofed storage, however, I need more roof space for the tractor that's in my woodshop, and the two 4-wheelers, and the dirt bike.  I have a 16'x40' loft that were going to be useful rooms, but so far it's wide open storage space for the first round of floor space clearing in the barn.  I knew I should have made the barn bigger from the git-go...
Car ports are pretty cheap and easy. I put up an open sided 24x40 with 12' sidewalls for air drying. To this I added a 12' wide lean-to on one side and will add one on the other side next spring/summer.
Cost was $6000 and the crew had it up in less than a day. It could be done cheaper if you didn't have to worry about snow or strong winds. Changing the roof steel to vertical (to shed snow) and going with thicker posts (to support snow and resist wind) added a good bit of cost.

(https://forestryforum.com/gallery/albums/userpics/46602/P8160046.JPG?easyrotate_cache=1534643703)
 

(https://forestryforum.com/gallery/albums/userpics/46602/P8160044.JPG?easyrotate_cache=1534643655)
 
We had a hell of a wind storm this summer that uprooted trees on this land and ripped the roof off a building across the street as well as others a couple blocks away. Was very happy (and surprised) the shed stood up to it.
Alan
Title: Re: Air drying without overhead cover
Post by: YellowHammer on January 25, 2019, 11:08:07 PM
Sometimes there just isn't enough roof.   :o

This place down the road from me has 2 million bdft on hand at any time.  They have stacks like this for I don't know how many acres.  A lot.  

(https://forestryforum.com/gallery/albums/userpics/21488/275209A2-6A4A-42F4-9BDA-75E5F6823C85.jpeg?easyrotate_cache=1517514552)
Title: Re: Air drying without overhead cover
Post by: GeneWengert-WoodDoc on January 27, 2019, 08:33:57 AM
YH, this picture is just about perfect...sticker alignment is awesome, stacks are close end to end to control end drying, stacks are straight in alignment vertically and along the rows, roof covers are fantastic, no weeds for good air flow, good water drainage after a rain, etc.  they should get a blue ribbon indeed.