Drying lumber


Jonathan McCully

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Going out tomorrow to get a large load of walnut cut fresh from the tree.  Until now I’ve always bought my lumber kiln dried, so this will be my first experience with non-dried wood. I understand that it will need to dry for quite awhile before use, but how should I store it until then? Do I sticker it and stack? And do I then need to buy a device to measure the moisture content so that I know when it’s ready to use? Just looking for some tips.  Thanks.

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12 minutes ago, Jonathan McCully said:

Going out tomorrow to get a large load of walnut cut fresh from the tree.  Until now I’ve always bought my lumber kiln dried, so this will be my first experience with non-dried wood. I understand that it will need to dry for quite awhile before use, but how should I store it until then? Do I sticker it and stack? And do I then need to buy a device to measure the moisture content so that I know when it’s ready to use? Just looking for some tips.  Thanks.

Store it somewhere safe from rain and pests. Yes and yes.

I've stored wood to be dried in my basement. If where ever you store it is humid and doesn't get a lot of air flow a fan should be used to stop mold from growing. It doesn't need to run full time so you could have it on a timer.

Stickers should be uniform in thickness so you don't but bows in your lumber. Also the base for the lumber should be flat. For lighter color species maybe this applies to walnut too, the stickers can stain the wood so using stickers made from the species is ideal.

They make pin meters where you can drive pins into the wood and run a lead to the outside to connect to your meter. Then you can measure the MC on boards in the middle of the stack. Electrophysics makes awesome meters that are simple to the point and work great. They put features where it matters not on bells and whistles and they keep their costs low. They also have amazing customer service, which isn't surprising because it's a Canadian company. They sell through an eBay store front.

If any thing i said contradicts Spanky Do what he said.

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As an added piece of usefulness, After they are stickered and stacked, run a couple or more  straps around the pile and pull them tight. Go back every few weeks and retighten.  As the moisture leaves the wood the straps will loosen. When they stop coming loose they are near  ballance in the moisture content.  Then you can either take them to a kiln, or figure on them being useful to work.

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Jonathan, please be advised from experience, that 8/4 is not the best way to go. I thought the same and even went as high as 10/4 for the slabs. Unless you have a bunch of live edge table tops and or legs to make, you will waste a bunch getting your stock down to 3/4”. My walnut was very stable after 2 years and unless I attempt to resaw an 8/4 piece, I loose a helluva lot planing it to my 3/4”. Just MO. 

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Making for yourself, or someone else? Knowing the final deztination environment can inform you how dry it really needs to be. Air dried to a stable moisture content in my area means 10-12%. But I made a table from thick material last year, dried like that, which is moving now, as its final home has a dehumidifier that I was unaware of, in addition to HVAC. The guy's house is 'kiln drying' the table, probably closer to 7-8% by now.

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I know some of this stuff may have already been said, but since I do a lot of air drying (currently have 5 stacks air drying now) here's my 2 cents. Proper stacking, stickering, covering and weight as mentioned above is key. Get the stack off the ground with cinder blocks and 4x4 posts. Then you can run a bunch of 2x4s across your posts, Make sure this base is level!

Stack it and use dry stickers or you could get mold where the sticker and lumber meet. Even though walnut is not as sensitive to sticker stain because of it's color, it's still good practice to use dry stickers. Use dry wood from you shop to make the stickers. I like my stickers to be at EMC which is around 10-12% for outside drying. Here's a photo of a stack of walnut I have had out for 2 years;

1033556671_lumber1.JPG.cda895d981dcad9db53544deee10de91.JPG

I use the off cut slabs to weigh my stacks down, also use roofing material to cover the pile and you need to have overhang with your cover. I also keep weed growth and grass growth down around the stack with roundup.

I actually like cutting my lumber thicker, usually 9/4, I think I get less warping. I just resaw if I'm building with 1" or 3/4 material. But, most of my builds lately have been requiring 8/4 stock.

As for drying, the old saying of 1 year per inch is just a general guideline. If you have warm weather year round than you should be able to get your lumber dried to EMC in about a year. Once you have it at EMC (10-12%) your risk of mold is pretty much gone. You can then take your air dried material into a controlled environment for final drying. I'd let it sit stickered for 6-8 weeks in that environment, then let it sit when you prepare your stock for a few weeks.

If you are testing moisture cut off a piece and test the middle of the board for a good understanding of where the wood is moisture wise.

Finally, I've built plenty of things with "wetter" wood (10-12%), the key is to understand that you need to account into you design for further seasoning when the item is brought into a controlled environment. Letting the wood finish off drying in a controlled environment is still the best.

Oh, one last thing, to minimize bug issues try to have the bark removed as much as possible (do as I say not as I do since a lot of the wood above still has bark on it). The bark and the starch rich sapwood is their favorite part of walnut lumber. I have no issues with the heartwood in walnut.

 

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8 hours ago, wtnhighlander said:

Making for yourself, or someone else? Knowing the final deztination environment can inform you how dry it really needs to be. Air dried to a stable moisture content in my area means 10-12%. But I made a table from thick material last year, dried like that, which is moving now, as its final home has a dehumidifier that I was unaware of, in addition to HVAC. The guy's house is 'kiln drying' the table, probably closer to 7-8% by now.

Just a follow up. I stopped by his house today, and measured 6.5% under the tabletop with a pin-style meter. Down from more than 10% this spring. That's with all sides having 5 or 6 coats of poly.

The 2" thick tabletop is turning into a scroll.

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I've only done this once, so I won't give you any "here's what you should do!" advice... I'll give you "here are the mistakes I made- don't repeat them!" advice.

I got about 200bf of 4/4 walnut from a local sawyer, rough cut. I brought it home about 2 weeks after it had been milled. I brought it into my basement, stacked & stickered it. I live in the Chicagoland area, this was early fall- basically this same time a year ago, I think I bought the stuff on October 3rd or 4th.

I didn't seal the ends- I think I should have. It dried FAST. The rule of thumb that I've always heard is 1 year per inch of thickness; I checked a few boards in January or February and they were already at 10%-ish moisture content- essentially dry. It was nice that it was already ready to use, but I think the first and last few inches of each board (the exposed end grain on each side) was basically useless- it was brittle and basically fell apart. So, I probably lost 4-6" from each 8-10' long board. I *suspect* that, had I sealed the ends with something like Anchor Seal, it would have dried more slowly and preserved the entire board (less trimming the end cleanly, of course) for use. Not a HUGE deal, but on a stack of 200bf, that's probably 10-12bf total basically just thrown away.

Second... we usually have a dehumidifier running in the basement, and this dehumidifier happened to be about 2' away from one end of my stack of wood. Well... I'd say that the 6-8 boards from the top of the pile, closest to the dehumidifier, experienced SIGNIFICANTLY more warping/cupping/twisting than anything else in the pile. And, it was just on the end of the board closest to the dehumidifier... not the whole board... it seemed pretty clear to me that putting the pile so close to the dehumidifier had a dramatic effect on the manner in which those few boards dried. Everything else in the pile stayed very flat, but those boards... essentially, the 3-4' from that end closest to the DH, I just had to cut those off and use them on their own, and in smaller sections- there was no way I would be able to use any of those boards whole. This was frustrating. I was able to work around it and still make good use out of all of the lumber, but I wish I hadn't screwed those boards up.

Moral of the story; seal the ends, and if you're running a dehumidifier, make sure it's nowhere near your pile of lumber!

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  • 2 months later...

Moving green lumber directly indoors, especially in the winter is not the best move. Wood needs to dry slowly or it will check/crack/split if there is too great a moisture differential between the interior and exterior of the board. 

Best to sticker green lumber outdoors, covered, with good air circulation until it reaches equilibrium (varies by locale). At least a year per inch of thickness. 

Then move indoors to acclimate. I normally move it into the shop an let it sit another year or more. Need to plan ahead! 

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