Replies

1. 
   johnhardy | Feb 10, 2005 09:18pm | #1

   I would guess that a professional kiln operator would charge about $.50 a board foot for drying. That'd make the cost of drying your material (2000 BF) about $1000. Seems to me that it'd be cheaper and easier to simply have it done professionally. And, this would give you a better end product (the operator knows how to do this properly, you might screw it up and destroy all the wood).

   John

1. 
   MrSQL | Feb 10, 2005 11:18pm | #3

   Acutally, one quote is for $150/1000 bd.ft. to dry it and $40/1000 bd ft to plane it.  I'll be generating a lot more wood in the future, so if making a kiln were cheap enough, it might be worth it; not so much from the bare bones cost, but the transportation costs there and back (it will cost me more to move the wood than it will cost to have it dried).  The wood is 1x6 red oak and 1x and 5/4 walnut and maple and has been air dried in a protected shed for about 6 -8 months. 

2. 
   frenchy | Feb 10, 2005 09:23pm | #2

   the lowest cost for drying wod is apiece of "tin" covering the wood. If you use a "shed"  you might slightly dry the wood a tiny bit faster but as I remember tobacco sheds are open to alllow air to flow thru them.

    If you were to "heat" the shed then great care must be used and the problems multiply.

     Several factors enter here such as the speed you'll need the wood to reach working range, average local tempurature, and type of wood.;

     It's fun to discuss such things so go ahead and ask your questions myself and several others will gladly help you and give advice.

      

1. 
   MrSQL | Feb 10, 2005 11:28pm | #4

   The tobacco sheds around here (central NC) use heat to produce "flue-cured" tobacco.

   The wood I have is mostly red oak (some walnut and maple) and has been cut into 1x6's (some 5/4).  It's been stacked and stickered in a well covered shed for 6-8 months. 

   I know that there is a real science to this and it's easy to ruin the wood.  Again, any drying advice will be helpful (e.g. what temp to raise the kiln to and for how long?   How much air?  what special controls are needed? 

   110 degrees for a week

   then keep at _____ degrees for ____ days or until _____

   finish at 140 degrees for 3 days  

1. 
   frenchy | Feb 11, 2005 05:25am | #7

   Roger,

    Walnut Maple and red oak are dramatically differant.  Walnut is pretty hard to ruin air drying,, keep it flat and straight and you've done all you can.. (I actually have dried a fair bit of black walnut without stickering it!) 

     Don't kiln dry the walnut if you can avoid it.  you'll find superior color and tone in the wood if you don't  .; 

        Red oak is more likely to decay so greater care needs to be taken.. the basic rule of one inch per year will work for air dried oak as well but you really need to buy a moisture meter.  You can make one from a kit, or buy an inexpensive one.; 

     Maple.. ah that's a rub!    The critical number is moisture removal to below the 17% rate.; That point is the lowest number that is possible  for mold to form.  I try to get maple below that number the first month.  then O slow up my rate of removal to deal with the strewsses I've induced..  

    the tempurature is less critical than the amount of water removed from the wood over time. too fast a removal rate and you risk honeycombing and other such drying stresses..

    What I would do is find out what your currant moisture levels are now and then from that point I'd check for case hardening, and other drying problems, I'd expect to find none in air dried wood.;  air movement is important simply because you do not want to have conditons that stress a few boards while failing to dry others properly.

     Once you get wood to less than 17% moisture  I aim for a 10% rate of removal I use a dehumidifier and measure the amount of water I haul from the room per day.; there are countless methods of achieving the same thing..

     Finally I wouldn't raise your tempurature at the end, rather I'd lower it and lets the stress of water removal relax,  that in the trade is called conditioning..

     By the way it's senseless to go for the lowest number possible.. If your ambiant level of humidity is 14 percent and you dry the wood out to 7% within a month after removal from the kiln the wood will measure that same 14%

1. 
   301 | Feb 11, 2005 09:51am | #8

   Hey fellas, he's down South with me and we have some serious humidity.   Everything will be different for him then it is for you Yankees, it may even be impossible for him to reliably air-dry in our climate.  I think he is on to a good idea.

   I have seen a local outfit that dries wood in a barn with a concrete floor.  They build fires under the floor with wood scraps and keep it burning for a long time, monitoring it closely.  It works as they do turn out good quality wood.

   We talk normal, you'all are the ones who talk funny and God talks like us.

1. 
   cherryjohn | Feb 11, 2005 03:51pm | #9

   I dunno....there was some mighty fine furniture made in his area before kiln drying came around that still exists to this day.  So unless you need the wood now and cant wait an year for it to dry then air drying gives a better end product, especially with walnut.

   And God is jus funnin' with ya'll.  He tries to passify all you boys south of the Mason Dixon Line.   I have it on good account that here lives on a mountain richt heya in NH.  Thats why we have no State income tax or sales tax!!  Wicked Decent Woodworks

   Rochester NH

   " If the women dont find you handsome, they should at least find you handy........yessa!"

2. 
   trialnut | Feb 11, 2005 06:41pm | #11

   Just read the King James Version and thou shalt knoweth how God really talketh, ya'lleth. ;>)The Professional Termite

3. 
   frenchy | Feb 11, 2005 07:24pm | #12

   el papa,

       I figured that out since he spoke about tobacco drying.. while there are some tobacco sheds near me in Wisconsin most tobacco grows in the south.

     Drying wood doesn't need heat and I'd be very careful about using it since it can induce a lot of stress.  As I said there is simply no point in over drying wood. Once it gets to the normal moisture level and all of the bond water (that's the water that is inside the cell of the wood from gowing)  is out of the wood then the wood is ready to use. A moisture meter tells you when you've achieved that.;.

     I wish you could understand that your location really isn't that differant than mine.;

     We get extremely high humidity in the summer here, we have well over 11,000 lakes in our state plus countless rivers etc.; Take a 90 degree summer day add that many lakes swamps and wetlands and you can see where our humidity comes from, in the spring and fall we get rainy seasons, enough to fill back up those lakes that may have dried up a tiny bit during the summer.;

    In the winter we get freeze and thaw except january when it's just bloody cold!   45 today and saturday and sunday we'll get a lot of rain..

     As for the mush mouth ya all speak about ............<G>:(ps, I figure Gods even smart enough to speak in your dilect since he speaks to me in mine)

   Edited 2/11/2005 11:26 am ET by frenchy

3. 
   cherryjohn | Feb 10, 2005 11:59pm | #5

   I guess my question is, since you dont seem to be in a rush to use this wood, why kiln dry it?  Walnut is one wood that looses something in its color when kiln dried as does cherry.  Since you are going to use the wood right there anyway( furniture and trim in your house) why not air dry it?

   Wicked Decent Woodworks

   Rochester NH

   " If the women dont find you handsome, they should at least find you handy........yessa!"

4. 
   pizza | Feb 11, 2005 12:11am | #6

   I was looking into kiln design on the internet a month ago and found many excellent articles with drawings too. Just do a search on Google.

5. 
   Wilson | Feb 11, 2005 05:14pm | #10

   Try Taunton press - Fine woodworking Wood and How to dry it 1986 ISBN 0-918804-54-x. It has all the scientific and practical information that you would ever want on wood drying