Wood drying technique

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Nov 26, 2007
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Eastern Pa
I read an article that described a method where you cut and stack your wood, then make a tent over it with 6mil poly and a light wood frame so the sun can warm it. The article claimed the moisture from the sun-warmed wood would condense on the poly and run to the ground. Has anyone tried this?
 
Haven't tried it. Interesting, guess the gain is from heat building up under the plastic? My thought would be that while the water would condense and run to the ground, the air around the wood would be pretty saturated during that process. While no cover would not raise temps, moisture would be free to leave and the air around the wood, would be drier. Much easier without a cover. Best way to tell is try it, one pile no cover, other pile with a tent.
 
Well, I'm going to try it. I have a lot of oak that I got for nothing that was cut into logs about six weeks ago. I'll cut and split at least one 4x4 pallet's worth, and build the setup as described. I'll report on how it works.
 
The Saran Wrap Company is gonna luv ya! :p
 
I would assume that the moisture release from the wood will stay in the air, as well as condense onto the inside of your "tent", thus evaporating at a much lower rate. This may negate (or even reverse) the speedier evaporation from the wood. I would think that air drying with a cover would be more efficient, as the relative humidity is much lower.
 
When dealing with green wood, I think it's best to leave it uncovered all summer and then put a tarp or some other covering over it before the snow falls. The idea is to drive the "bound" water out from within the wood cell walls, and I think that happens easier with lots of direct sunlight and dry air moving through the pile. Once the bound water leaves the wood, it can get wet and dry out again very quickly, but a tarp will ensure that you have dry wood when you need it, and staying dry protects the wood from rotting. The reason for not tarping a stack of green wood is that, IME, it slows down the process of driving out the bound moisture, which is really what "drying" is all about.

If you take a piece of dry wood, soak it in water and then let it sit in the sun for a day or two, it will be dry again. A piece of green wood, on the other hand, can sit in the sun for months before it dries out.
 
If you take a piece of dry wood, soak it in water and then let it sit in the sun for a day or two, it will be dry again. A piece of green wood, on the other hand, can sit in the sun for months before it dries out.

I would have agreed with you on this, but I did this with a piece of firewood that had been dry, but then got wet again. It took five months for it to dry out, based on its change in weight. The difference may be that I didn't just soak it for a day or so, it was out in the rain for weeks or months. I'll post what I found in another thread.
 
ThePhotoHound said:
I would assume that the moisture release from the wood will stay in the air, as well as condense onto the inside of your "tent", thus evaporating at a much lower rate. This may negate (or even reverse) the speedier evaporation from the wood. I would think that air drying with a cover would be more efficient, as the relative humidity is much lower.

I think the key is that the wood cannot be covered with the covering material in contact with the wood. The cover needs to be elevated from the top of the wood pile. I would say a minimum of one foot but I would shoot for two.
 
I'm sorry if I wasn't clear.
CTpelletburner has it right; keep the plastic above and around, but not in contact with the wood. Leave a couple of inches airspace above the ground, for some air flow.
The article said this setup was for drying wood in a hurry, and produced a lot of moidture on the plastic, which ran down to the ground, every day, and dried the wood out in 6 weeks.
 
I am with Eric on this one..this is my second year. the first year I stacked the piles and covered right away..this year I stacked and did not cover until Early October. I believe that the wood is better this year than last plus both were stacked about hte same time give or take a week
 
Sounds like a design for a solar drier. The design of the drier might work well if you put a good sized vent (1 square foot?) in the top & have a few inches of open space (maybe 6-12) around the bottom. With the sun shining this would set up a good convention flow...the sun would heat the air & wood inside, the hot air would rise and exit the vent, cooler dry air would be pulled in from the bottom & the cycle would continue. Without the vent in the top all you have is a humid greenhouse & I doubt it would work very well.
 
why mess with all of that?? split/stacck and let dry for at least 8 months and you will be fine.
 
Adirondackwoodburner said:
why mess with all of that?? split/stacck and let dry for at least 8 months and you will be fine.

DU-OOH, I would revise that, cut, split, stack and let it dry for 2 years. Cleaner burns, faster starts, less creosote.
 
2 years?? thats a bit extreme..wood will only get to a certain moinsture level and will not get any better due to climate conditions. I would think 12 months is plenty.
 
Here's a link to the study that I mentioned earlier: http://www.fs.fed.us/pnw/pubs/pnw_rn450.pdf


Seems pretty thorough - their conclusion was that a pile with a cover on the top to keep out the rain was the best approach.

I've got my piles running east-west with about 9 feet between them so that they get maximum sun and air circulation. There's a cover that just overhangs the sides.
 
yes, I use old metal roofing..works well
 
WarmGuy said:
If you take a piece of dry wood, soak it in water and then let it sit in the sun for a day or two, it will be dry again. A piece of green wood, on the other hand, can sit in the sun for months before it dries out.

I would have agreed with you on this, but I did this with a piece of firewood that had been dry, but then got wet again. It took five months for it to dry out, based on its change in weight. The difference may be that I didn't just soak it for a day or so, it was out in the rain for weeks or months. I'll post what I found in another thread.

Yes but weeks or months exposure to rain gives it very little time to dry out and I think he was referring to the normal occasional rain and not a climate where it rains every few days...
 
Essentially you would be building a solar kiln.

The best way is to eliminate ground moisture so that the whole area is enclosed.

Then add a fan for circulation.

With good southern exposure you could kiln dry a cord in a matter of weeks.

Here is a plan for one to dry lumber for furniture making.

http://www.woodscience.vt.edu/about/extension/vtsolar_kiln/

Fairly simple idea, just depends on how far you want to carry the construction.

J.P.
 
Interesting read nofossil, but the big argument we have here is covered vs uncovered. They did not leave a pile uncovered in that study. Oh well the debate goes on!
 
wxman said:
Interesting read nofossil, but the big argument we have here is covered vs uncovered. They did not leave a pile uncovered in that study. Oh well the debate goes on!

Must be a federal grant opportunity in here somewhere....
 
Adirondackwoodburner - 28 November 2007 01:54 PM
why mess with all of that?? split/stacck and let dry for at least 8 months and you will be fine.

author="Adirondackwoodburner" date="1196291486"]2 years?? thats a bit extreme..wood will only get to a certain moinsture level and will not get any better due to climate conditions. I would think 12 months is plenty.

OK.. I am not about to debate you, you burn the 8 month old baby and I will burn the two year old! :coolcheese:
 
????? Oh I understand, S Jersey........
 
Adirondackwoodburner said:
????? Oh I understand, S Jersey........

Some people are extremists... they love to burn their house down and give advice to others how to do it. We avoid that in S. Jersey!
 
I avoid S Jersey altogether.
 
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