Drying time

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Bill

Minister of Fire
Mar 2, 2007
584
South Western Wisconsin
Has anyone compared the drying time of splits, relatively the same diameter, at various length's? Let's say 16", compared to 22" etc. It would seem to me the longer the length the longer the drying time, but I have never checked.
 
I don't think length is as relevant as diameter in drying, I have 16-18 inch splits and some that another cut that were over 22 inches and they both seem as dry as the other.

Shipper
 
Humm...I was thinking just the opposite. I've been splitting a bunch of oak from a scrounging trip...a lot of pieces are 24" diameter or bigger. It's been on the ground for 18-24 months, but it's been cut into 20" lengths. Stuff is dry as a bone. A couple of years ago, I cut down an elm tree (I know...what was I thinking!, but it was blocking access to a nice hedge tree) so I cut it down, but didn't have a chance to buck it into logs for a little over a year. Bark was falling off, twigs snapped right off but the trunk was still very wet. Sometimes even beads of moisture would form on the fresh saw cut.

We had a great study posted on covered vs. uncovered wood, but I don't think anyone has ever formally looked at it.
 
I read somewhere that it is both but the wood loses most of its moisture thru the ends so the longer would take more time to dry.
 
For a given volume ( piece ) , the greater the surface area the faster it can dry.

You cut a 22' pice shorter , you'vr increase the surface, you split it- same effect.

The more pices you make the faster it dries.
 
Wood looses most of it's moisture via capillary action out the ends of the pieces. Thus the shorter the round the less distance it has to travel to get to an end. Not sure how much of a difference it would make between 16 and 24", but stove length dries MUCH faster than four footers, or log length...

I always advise that if faced with a choice between cutting wood to stove length and splitting it as you go, that cutting should take priority.

Gooserider
 
I'm a new b but i've had some damp logs that i left in the furnace room and they dried in a few days. I tossed them in the furnace and they were just fine. By the way, what would/should be the moisture content of the logs & where can i get a moisture meter?
thanks
 
davejerry said:
I'm a new b but i've had some damp logs that i left in the furnace room and they dried in a few days. I tossed them in the furnace and they were just fine. By the way, what would/should be the moisture content of the logs & where can i get a moisture meter?
thanks

There are two different issues here - "dry" and "seasoned" - A log can be seasoned and not dry, or vice versa. A lot of this relates to "bound" vs. "free" water. Free water is the water that is in the log's capilary system and in between tissues, and is not chemically bonded to the actual cell structure of the plant - think sap. Bound water is water that is part of the actual cellular material and is only released slowly as the individual cells start to break down as part of the normal decomposition process. When bound water releases, it becomes free water. Free water evaporates, mostly from the ends of cut logs. "Dry" wood is wood that has lost most of it's free water, while "seasoned" wood has had most of it's bound water. The drying process is much faster than the seasoning process, and both need to get pretty well completed in order for the wood to be truly ready for burning.

There have been people that have tracked the moisture content of their wood, and found that it initially drops off fairly quickly when first cut, which represents the free water evaporating, and then goes into a much slower decline as the bound water gradually releases. If dry or seasoned wood gets wet again, the water is mostly taken in as free water, sort of like a sponge, and because it isn't bound, will dry fairly quickly, especially in a warm, low humidity environment.

Ideally firewood should be somewheres between 15 and 20% moisture - lower than that (as in most lumber cutoffs) and it tends to burn to fast / hot. Higher and you get less than optimal burning and heating from it because you are trying to drive out moisture at the same time you are burning it.

Moisture meters can be had at lots of places, E-bay and Harbor Freight seem to be among the more popular sources. They come in two-prong and four-prong versions, I've seen several people report that the two-prong versions are easier to use on the rough surfaces of firewood. (The four prong models are more accurate, but need a smooth surface (i.e. lumber) in order to get equal penetration on all prongs) The accuracy of the meter is not a big issue, as mostly they are to give a general idea of where you are at with the wood.

Gooserider
 
Thank you for getting back to me so soon. One other thing, if i may, I don't have the forced draft air fan/kit. Is this a must have or can i get by without it?
 
davejerry said:
Thank you for getting back to me so soon. One other thing, if i may, I don't have the forced draft air fan/kit. Is this a must have or can i get by without it?
Not sure what you are talking about here, and would be off topic for this thread in any case.

It might be better if you could start a new thread in the appropriate area - i.e. boiler room if it's a furnace, hearth room for cordwood stoves, etc. (Not a big deal if you get the forum area wrong, us moderator types can move threads if needed) We will also need a bit more context, like what kind of equipment you are looking at the fan being for, and whether the fan is something intended to pump air into the firebox for combustion, or if it's supposed to help push heated air around your home...

Gooserider
 
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