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Post Oakie
Post Oakie's picture

That's learning the hard way! I expect most of us have been there.

As for the cottonwood, how do you plan to use it? Air drying generally won't bring wood down to kiln dry moisture content, no matter how long you leave it, but the dry climate in western Kansas would get you close. A year for the 1" and two years for 2" is the rule of thumb. It will probably reach its driest in early fall after a hot, dry summer.

eddiemac
eddiemac's picture

Though I have no experience with cottonwood, I have read authoritative sources who claim: "Cottonwood dries quickly, but has two major problems - certain regions of the lumber have a tendency to collapse during drying, and the wood likes to warp." They suggest close sticker spacing and rapid drying and add that collapse can be reversed at the end of drying (7% and not before) by exposing the lumber to moisture (even if it's just water-based finishes).

Seasoned Carpentry
Seasoned Carpentry's picture

Kiln drying is no panacea. Once out of the kiln, the wood takes on the moisture content of wherever it is stored. It doesn't stay kiln dried. Air dried takes on that same moisture content, so soon enough both air dried and kiln dried wood stored in the same place end up with the same moisture content.

Here in the Northeast, moisture content in houses varies a lot with the seasons. Furniture swells and shrinks with the seasons. If you don't build to accommodate this movement, the furniture will suffer. Winter in a heated dwelling is very dry, summer very humid.

The last house I built I was determined that the hardwood flooring wouldn't shrink, so I bought the birch flooring from local sawmill air dried and planed. Then I stickered it in the house over the winter and installed it that spring. In the summer the floor expanded! I'd dried it too much. There is such a thing as too dry here in the Northeast. That's why I'll air dry my wood and forget the time and expense of a kiln.

eddiemac
eddiemac's picture

Seasoned Carpenter: I understand your point of view. When building, the moisture content of the materials and the structure they will be in have to be taken into consideration. Kind of a guessing game as to what the future will hold. Will the house be climate-controlled in summer and winter? I like my solar kiln because I can get the moisture down to 7% in a relatively short period of time, take the lumber to my shop in the summer and build something without worrying too much about shrinkage. If I only built in winter, I would just take it into the shop, sticker, and dry it beside the wood heater and not bother with a kiln. But it's a good tool to have if you've got the time, money, and space to build one.

Post Oakie
Post Oakie's picture

Most of the problems created by kiln drying, including collapse and case hardening occur because the commercial kilns try to push lumber through as quickly as possible. With high temperatures and a high moisture content difference between the inside of the board and the surface, the outside of the board actually squeezes the inside, which has been softened by the heat. This causes the cells on the inside to collapse. Adding moisture at the end of the drying cycle is meant to equalize the moisture throughout the board, but will not repair damaged cells. The slower cycle and lower temps of the solar kiln avoid the problem, plus the board has a chance to equalize the moisture content every night. I hope to have one similar to Eddiemac's up and running this summer.

Seasoned Carpentry
Seasoned Carpentry's picture

Yes the kiln is faster. But in your case, drying wood in the summer to 7% and using it in the shop means you have to worry not about shrinkage but about expansion. Outside your kiln the summer moisture is much higher than 7% and your wood will begin to expand as it takes in moisture. If you build too tight without planning for the expansion, you'll suffer the problem of expanding wood.

The solution to the guessing game is to anticipate both expansion and shrinkage on an annual basis when creating pieces. There is no one indoor moisture content, it varies seasonally. That's why air drying is as good as kiln drying if you create a year's worth of wood ahead. You'll then always have dry wood to use. That's my situation and I love having a stash of dry wood waiting.

eddiemac
eddiemac's picture

I figured you'd say that (expansion). But in my case, I'm so slow that whatever project I'm working on regains enough moisture in the shop to make things even out. Building to minimize the problems of wood movement is, as you say, the way to go. It appears you are a wise, seasoned carpenter.

Bill
Bill's picture

One good reason the kilin dry is to set the pitch to avoide it bleeding out after the project is completed.

Bill

Post Oakie
Post Oakie's picture

Good point. For hardwoods, if you can hold 130 deg F for a few hours, you'll kill any bugs. Anyone who has experienced powder post beetles in their home will agree that bugs are bad.

How do we cut 2-by lumber fem center of fir logs to prevent them from twisting when air dried? Thanks

Brian

Bill
Bill's picture

Brian I've used a lot of fir over the yrs. building and I find if it's going to twist not much will stop it. This is what I do after sawing it and for the most part turns out very well.



If the edge of the 2x4 the strap goes over is beveled a bit it's much easier to tighten the strap and you have to tighten the strap every few days for a while unless you have another lift on top.

Bill

Dewchie
Dewchie's picture

Nice pics Bill, wanted to post the same on your steps to sawing up a log but every time I view that post it assumes I am not logged in. Great Job!

Cheers!

Steve

how to deal with fir twisting. I just received and order for 20' 4x8s. Question: if I cut them green and the beams are built in place with the next few weeks - it is super dry here in norther CA right now, will the beams twist? Thanks,

Brian

r.garrison1
r.garrison1's picture

A lot of twisting and warping is because the wood dries faster in one part of the board than in another. You may want to check into something to stabilize the wood, so it dries slower and more evenly. Not sure what would be best for green lumber, though. Is is softwood or hardwood?

its what they call suppressed fir. we have 300 acres of 12-18 inch Doug Firs that are 90 years old. They are so hard that harwood flooring is made from these trees. And, the mill is on a hill in super dry norther CA with 90 degree days and now rain until Nov, but my buddy needs the beams right away.

thanks for you help

r.garrison1
r.garrison1's picture

Bill,

I was noticing the ratchet straps, and I was wondering if a bander would be worth the expense. I remember my first real job in a stud mill, everything was banded. It was so quick and easy to do, there wasn't a reason not to.

Has anyone tried that?  I't looks like Bailey's, Northern Tool, and Grainger all have some options, but it would run $1000 +/- to get started, and I don't even know if the banders you get for that would be adequate.

Post Oakie
Post Oakie's picture

I used a bander back when I was cutting railroad ties.  It works fine, but as the wood shrinks, the bands loosen.  You can solve that problem by driving wedges under the bands to tighten them.  Notice that Bill only strapped the top group of boards, and let its weight hold the ones below it.  There is also a banding system available from Uline.com which is a lot cheaper.  I believe it uses fiberglass strap and requires no special tools.  After losing a load of logs off your loader, you'll soon come around to the idea that it is good to band all bundles.  Whether it is cost effective depends on how much lumber you produce.

Bill
Bill's picture

I have a bander but like Oakie says the wood shrinks and for the 1st wk. or so you have to deal with it every day , with straps there's enough tension you can go for a few days in between tightening for a wk. or so then I check them once a mon. for a short while.

Thanks guys.  I've just found a banding machine second hand to buy.  Your comments are a big help.

 

Does anyone know about Madron?  I cut a 5 ft diameter madron tree that died last year and am wondering if the seasoned parts of it will warp and twist if I cut slabs for tables and furniture, esp., where branches come off the main stem?  Thanks,

 

Brian Hill

Hyampom, CA

3000 ft alt.

 

Bill
Bill's picture

Brain it's handy to have a banding machine if the price is right I use mine for binding the slabs and lumber I'm going to sell when I haul it. Never heard of that type of tree but live in a little lower alt. though the mt. we live on goes up to 6,000 ft. Oakie probably knows about thoughts trees.

Tree_Climber
Tree_Climber's picture

Hello,

I was wondering if anyone could help me out.

I have a 3 foot, 11" diameter birtch log.

I'm looking to dry it and use it to support the table top I have already dryed and sanded down.

I don't have a kilen to dry the log so what would be the best option to go about doing so?

eddiemac
eddiemac's picture

Just put it some place where it won't get rained on and, ideally, is out of range of boring insects like the powder post beetle, leave it for a couple of years, and then use it.  Or  ---   live dangerously and build with it now, keep an eye on it for a year, and then release it to the world.  Shrinkage shouldn't be much of a problem, but applying a finish might be if it's not dry.  (P.S.  I know practically nothing about birch).

r.garrison1
r.garrison1's picture

Here's a trick. The end grain dries faster, causing cracks. Bore a hole about 1" or so diameter in each end, about 3" deep. With luck, as it dries, it will contract the hole a bit, but not crack as much on the end grain.

For extra points, you can make some relief cuts through the hole with a skilsaw; a couple inches out in a radial pattern (like compass points sticking out from the center).

smithbr
smithbr's picture

Question:

From what I've seen, the bottom layer of nearly every stack gets enough moisture, or so poor air circulation, that it's sacrificed to mold.  Would any of the following help or hinder in your opinion:

- Lay a sheet of plastic on the ground below the stack to prevent moisture transpiration from the ground accumulating on the bottom boards of a stack

- Lay a sheet of plastic above the bottom sleepers of a stack, but below the first boards (maybe, two levels of sleepers?), to allow ground moisture to evaporate and at the same time allow that first layer of boards to breathe

- wrap that first layer of planks in sheet plastic, to protect everything above (sacrificial layer, taken to the ultimate)?

 

I ask, because I'm about to move my existing lumber stacks to my new shed, along with cutting my last 45 or so logs in my old location. Stacks in the new location may need sleepers cut, plastic placed, etc. and I'd like not to waste my time and money, but I want what I move to be protected and preserved.

smithbr

 

Bill
Bill's picture

I just keep mine 6" off the ground and don't have any problems but know that if you have any plastic next to the wood it's going to rot . Plastic on the ground under the sleepers would be effective if you could keep water from pooling under the stack on the plastic. Gravel or drain rock may be a better solution. Here's and example of one way of doing it. 2 sleepers length wise then the cross sleepers on top this raised the pile up and also keeps it level.

I'm sure there may be better ways but this is all I've come up with trial and error.

eddiemac
eddiemac's picture

My drying shed has a layer of base rock for a floor.  The stacks are on 6" high crossbeams which rest on that gravel.  Have never lost a board.

smithbr
smithbr's picture

Thanks.  Right now, my floor is sand.  I was reluctant to add stones to my log yard.  I think the soil will dry quite a bit now that the roof is up, so a double level of 4x4 or 6x6 may be sufficient to provide ventilation.  Since the stacks will be under-roof, I'm not too worried about water pooling, so I might try plastic as well.

 

Post Oakie
Post Oakie's picture

I use Bill's technique.  If you get the stack up off the ground, there will be no problem with moisture on the bottom layer.  I use metal roofing over the top of the stacks instead of tarps.

Bill
Bill's picture

Metal on the stacks works well allowing for ventalation the lumber tarps I use i get for free from the lumber yd. so that's the only reason I use them but I space them enough above the pile to allow air flow.

Front Range Sawyer
Front Range Sawyer's picture

My son has 35 acres on the front range outside of Denver that the county has stacked 200+ logs from trees that they felled as part of a fire mitigation effort. He has purchased a Norwood MN 26 mill so he can mill the logs into timbers for his Timber framed home. We have about 30 timbers ranging in size from 4x6 to 10x10 by 16' that are neatly stacked in air drying racks with sand bags ballast weighing them down. What is happening is the timbers are cracking and splitting. We think it is because the doug fir and pine timbers are drying too quickly even though we have the stacks covered and the ends of the timbers are sealed. WE think if we coat the timbers with raw linseed oil  that this will slow down the drying and keep the timbers from cracking and splitting. Any comments? Are we on track?

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