Goose I think you have the right idea but you're not explaining it well. Humidity is the amount of moisture in the air expressed as a percent of the total amount of moisture the air can hold. For example, if the humidity is 50% then the air is capable of holding twice as much moisture than it's currently holding. If the humidity is 100% then the air can't hold any more moisture. The dew point is the temperature at which a body of air must be cooled in order for the humidity of the air to rise to 100%. Therefore, as long as the the temperature of the air is GREATER than the due point of the air, evaporation can occur.
Time to cover wood
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karl said:
Exactly, and what I've been saying all along - it is mostly just a question of which variable you hold as a constant... I look at it from a "solutions chemistry" standpoint, - how much solute (water vapor) can the solvent (air) carry, which is a function, in part, of temperature. The dew point is when the air/water vapor solution reaches "saturation". If the amount of vapor in the air is less than saturation, then further evaporation will occur. If it is oversaturated, you will get the excess falling out of solution (dew) The less saturated the air is, then the more readily the solute goes into solution (evaporates).
Gooserider
Hmmm, good idea! Sounds like yours was inexpensive enough and doing the job, great suggestion! Thanks!
We hadn't planned to cover our wood piles until October, but I wish we had done it a couple weeks ago. Unlike Bob the Builder, who is having hot dry weather, I am in WI, land of monsoon rains. We keep seeing local areas on the national news, flooding everywhere. Fortunately we live at one of the higher points in the county, so we just get soggy ground and small puddles all over. I have a lot of wood to split still, and it seems to me that really rain soaked wood isn't going to be as easy to split, and definitely messier to handle. Meant to split wood during the summer, but it was so unbearably hot for so long. Terrible heat, then monsoon rains, hmm. I think Wisconsin is turning into the south of India weatherwise?!?
karl said:
Karl, Your terminology is still a little off. Humidity is the true amount of moisture in the air. Like in the winter the humidity is lower then the summer even if the relative humidity in the winter is higher. Like when its snowing the humidity is near 100% but the moisture content of the air may be less then a hot sunny summer day. The term you should be using here is "relative humidity" the amount of moisture in the air relative the the amount the air can hold. Goose, man that is a twisted way of looking at it, I kinda get your point but there is no way I know of to quantify your statement. In other words you cant put numbers to it. For instance if the dewpoint is 60 deg, what humidity is lower than that? What are you measuring thats lower then the dew point?? If the relative humidity is 70% (a higher #) your still getting evaporation. Please, if you can, quantify your description.
You guys are making my head hurt with this dew point humidity stuff.
I'm trying something new this year, I don't get alot of sun in my wood storage area, so i'm hoping to get a little solar gain out some black tarps. My wood has been covered all summer so far. Usually don't cover til late fall.
I'm trying something new this year, I don't get alot of sun in my wood storage area, so i'm hoping to get a little solar gain out some black tarps. My wood has been covered all summer so far. Usually don't cover til late fall.
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does this mean i messed up or what? i'v had my covered since april 07 Just the top though, should i pull my tarps off or leave them? i thought wood dried from the ends anyway? didn't think covering top would harm anything. plus is was reading on this forum that wood will absorb rain and prvent it from drying???? this seems to be a little conflicting?
Wxman, we had the colder air can't hold as much moisture discussing awhile back, but you are correct. I should have said relative humidity.
Can you tell these guys i'm not crazy when I say you can water in a liquid state at a temperature well below freezing?
Can you tell these guys i'm not crazy when I say you can water in a liquid state at a temperature well below freezing?
Your not crazy! Guys he's not crazy! 
here's a link to some cool videos showing supercoold water in real life situations.
http://f0rked.com/articles/supercooling
here's a link to some cool videos showing supercoold water in real life situations.
http://f0rked.com/articles/supercooling
rich81 said:
You'll be fine. The cover or not to cover debate will go on for ever. There are many different factors into proper drying, but the basics are to keep it off the ground and stacked in a good sunny spot with good air circulation. I always thought the best thing to do was get 1 or 2 years ahead.
wxman said:
I don't normally try to quantify it - my point is mostly that unless there is so much moisture in the air at any given temperature that condensation is occurring, then some level of evaporation is occurring.
In psudo-code -
IF {{occurring != condensation}
THEN {occurring = evaporation}}
If I HAD to quantify it, I would define the dew point at any given temperature as the maximum percentage of the mixture of gasses we call "air" that can be composed of water vapor. The lower the temperature, the lower the allowed percentage of water vapor ("allowed" being defined by natural law / physics, not the Weatherman's version of the NFPA
). If the percentage of water vapor exceeds the allowed amount then you get condensation until the percentage drops to the allowed maximum. If the percentage is less than evaporation will occur from any available source of water vapor until the maximum is reached. The RATE of evaporation will depend on the difference between the allowed amount and the actual.Gooserider
If the ambient temperature is higher than the dew point water is evaporating. Period. Game. Set. Match.
But according to how you are storing your wood, the temp of the wood may not be the same as the ambient temperature. In fact if it is losing water then it will be lower than ambient because evaporation is cooling the wood. ;-)
All of this does not matter. When the poop hits the winter fan, it goes in the stove.
But according to how you are storing your wood, the temp of the wood may not be the same as the ambient temperature. In fact if it is losing water then it will be lower than ambient because evaporation is cooling the wood. ;-)
All of this does not matter. When the poop hits the winter fan, it goes in the stove.
Todd said:
I would even break it down further - the two key factors are to encourage evaporation and to prevent reabsorbtion of water - wood really isn't all that different from your laundry in this regard, just slower to dry. If you look at all the advice on how to dry wood, it all falls into one or the other of these two factors, sometimes both...
Getting the wood off the ground removes a major source of moisture re-absorbtion.
Air circulation replaces moister air that has already pulled some moisture out of the wood with fresh, presumably dryer air that can absorb more.
Putting it in a sunny spot encourages solar gain, which raises the temperature, again increases evaporation
OTOH, rain is a source of moisture to be reabsorbed, the question being how much of a moisture source it is.
Covering is mostly controversial because while it stops rain, it can also interfere with evaporation by restricting air circulation. This leads to endless debate as to whether you get a net gain from preventing reabsorbtion, or a net loss from reduced evaporation.
I put my wood in a woodshed right after splitting, which covers it, but may not give as much air circulation because I'm stacking 5 rows across in one shed, although it's open on both sides so air can flow through the stacks. The other shed is only two rows deep but the back is blocked by tarps, so it's really only open on the front, which restricts air circulation. My wood gets dry, but whether it does so faster than it would if not covered, I have no idea.
Gooserider
this is a subject that will go on forever. i've always kept the top of my wood stacks covered and the sides open. then i switched to using black plastic on top with about a foot on each side over the top the top three rows of splits, under that black plastic dried in a matter of 2 to 3 months depending on what type of wood was under the plastic. and the rest took the normal year or so. this year i kept all the covers off and other than the normal top three rows of splits being dryer than the rest it's drying the rest of the stack a little better. i find even after a heavy rain the wood is only damp for about three days and then it continues it's drying. all in all what works best for me at this time is leaving the splits uncovered until we get into the burning season. i wood like to try a experiment sometime and cover the whole stack of splits with black plastic with some slits cut in the sides and see how well it would do. and by the way in my experience the wood does dry through the winter if there is no snow covering it.
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