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I have what is supposed to be a simple question about drying green lumber. Before you tell me to check the archives, I tried and keep getting “no results” responses, so obviously I don’t klnow how to use the system. I appreciate the commenst that you will invariably send about how to use the archives, but skip it. All I ask is a simple answer.
I have some green lumber drying in the back yard. Stickers between every layers. Plastic tarp that almost touches the ground. Heavy weights on top. Does it matter if the plastic is clear or black? Why?
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Better to dry in open air than under plastic...like open air post and beam structure.
near the stream,
aj
you can also seal ends of boards.
*Mr. Ed,Outside under plastic is a bad idea. Put it up in the attic of your house or garage and wait about three years. The sticks are right on. Get a moisture meter and check it once in a while.However, I don't trust those things. The points only penetrate the first 1/16' or so. You can't tell how dry the center is.Good Luck,Ed. Williams
*At least roll up the plastic so it isnt any more than a roof to keep the rain off. The stickers are to encourage air flow between your boards and your current set up is discouraging it. Rule of thumb I've heard is 1 yr per inch. If it's in the sun and you start seeing alot of rapid end checking, its drying too fast and you'll need to wet it down and shade it.JonC
*Ed --It would be helpful to know the wood species. All woods are not alike.You may want to go over to the "Knots" discussion board for info there. We fine woodworkers tend to discuss issues like this on a fairly regular basis and the info you are seeking may be archived there.First thing is to get it off the ground -- 18" would be a good idea. Get your bunks level or you will induce warp. Depending on the species you should be stickering at 12" to 18" intervals (and therein placing your bunks). Use dry stickers or you will get mold or sticker stain. Make sure your stickers are vertically aligned (straight). Stickers should be about 3/4" thick by about 1.25" wide. If you are in an area that is very dry and hot, you may want to reduce the thickness of the stickers slightly.Do not place the pile in direct sunlight and orient the pile so the length is perpendicular to the prevailing winds.It is advisable to have a roof of sorts that will shed water, and top weighting is advisable as well. Mills are using slabs of reinforced concrete up to six inches thick as top weights.Rather than plastic on the sides, it is advisable to get shade cloth and if that is not available, then use burlap. You want something that is porous and will breath. If you seal the stack and do not get good air flow through the stack, all that wet wood will be a dining delight for mold, bacteria and fungi.Regularly monitor the stack for possible insect infestation. Termites, carpenter ants, powderpost beetle and hundreds of more insects can use the pile for food and/or habitation.You never get something of value for nothing. Consider the value of that lumber if you had to purchase it -- and use that as justification to make the necessary investment of materials to process it correctly. That also includes end-coating all the boards. Also recognize that air drying will never reduce the moisture content enough for interior products like furniture (that requires a MC of about 6-8%). Air drying will get you down to about 15% +/- depending on your locale.The USDA Forest Service has published many books and pamphlets on drying wood. The Forest Products Lab in Madison WI is a good starting place for reference citations as is the Lab in Princeton WVa regarding hardwoods. They can be access on line with a web search (sorry but I cannot locate their website address). If you give me some indication of your location I might be able to steer you to a Forest Products/Wood Utilization department at some university. YOu might also want to see if there is a forestry extension agent in your area. A good book for understand the wood drying process is the Dry Kiln Operators' Manual and that can be obtained from any US Government Printing Office. I think it is costing somewhere between $30 - $40. I also have two other references from the Forest Service -- Air Drying Lumber (Ag. Handbook # 402) and Drying Eastern Hardwood Lumber (Ag. Handbook #528). If you are dealing with some minor west coast hardwood species like tanoak or pepperwood or Goldenleaf chestnut -- contact me directly as I am lead author of a publication entitled "Hardwoods of the Pacific Northwest".If this doesn't answer your initial questions -- post on!!!
*Wow!...Beyond knowledge as possible on planet Earth...near the stream, and mildly impressed Stanley Steamer,ajStan...If I build a Wells Cargo trailer into a portable trim supply rack and kiln, how long would it take to dry pine and oak to be suitable for use in the Lake George region?...thanks in advance.
*Stanley,Man,You guys take this WAY too seriously.Ed. Williams
*OK, Stan (may I call you Stan?). I wanted to keep it simple, but you've opened a floodgate. I'm in south Texas. Sometimes it rains here (total for July & Aug 0.1"). The sun always shines. Most of the wood is cedar elm, some white oak. It's raised about 4" off the ground, stickered with strips 1/2" thk ripped off new cheap studs. Most of the boards are 6-7 ft long, and there are three rows of stickers, so they are about 24" apart. I used clear plastic because that's what I had, and I had read somewhere that the boards should not dry too quickly. I cut the plastic a little short of the ground so some air could circulate; it's definately not sealed, but it's not as porous as burlap or shade cloth. I think I need to get a sheet of plywood for the 'roof' because right now the plastic droops and conforms to the top layer of wood (the weights are on top of the plastic).A question about kiln vs air drying. I realize that the mc will never get as low when air dried. When I buy wood from the gettin' place, it's been sitting in their un-conditioned warehouse for a while, and when I get it home, it sits in my garage/shop waiting to be used. Doesn't it absorb moisture to roughly the same % as the open air? What keeps the kiln dried wood at the mc that it was when it left the kiln?
*stanley.... good to hear from you again... you been lurkin just waitin to pounce ?
*I have to disagree with the statement that air dried lumber will never get dry enough for inside projects. I took several hundred feet of Douglas Fir 1 x to a local kiln about 18 years ago so I could use it for flooring. It had been air drying for a couple years. So I take it in there and about two days later the phone rings and the guy at the kiln says "we can stick this in the kiln if you really want, but it ain't gonna get much drier". So I go in there and he puts a meter on it and sure enough it was 6-8%. I live in Western Washington, and the ambient moisture here in winter is beyond description.
*Ed, Adirondeck Jack, Jim B., et. al:Serious -- hell this is funIn the USDA publication "Storage of Lumber" (Ag. Handbook 531) they have a table of Estimated average wood EMC conditions for all states.For Texas they give Coastal and InlandCoastal - spring = 15.1%, summer = 14.2%, fall = 16.1%, winter = 15.5%Inland - spring = 12.0%, summer = 10.2%, fall = 12.5%, winter = 12.3%For coastal Washington the values are spring = 14.2, summer = 13.8, fall = 15.7, winter = 17.0. Unless you live in Neah Bay where a friend of mine spent a winter and said it was the only place in the world he has seen it rain horizontally for three days straight. For him a break in the weather was when it rained more vertically than horizontally.For NY, the following values are published as spring = 13.1, summer = 12.8, fall = 14.1, winter = 14.8.I think with 24" sticker spacing you will get considerable sag between the stickers.In Drying Eastern Hardwoods, the following times are published: (days to attain a MC of approximately 20%).Cedar elm (South region) 4/4 = 50 - 80 days; 8/4 = 190 - 230 days.White oak (South region) 4/4 = 60 - 120 days; 8/4 = 240 - 360 daysWhite oak (Mid- North) 4/4 = 70 - 200 days; 8/4 = no dataRed Oak (Mid-North) 4/4 = 60 - 165 days; 8/4 = no dataThese publications deal only with hardwoods but if you look at basswood which has a similar density to eastern white pine for 4/4, they publish a range of 40 - 120 days and have no data for 8/4 lumber but the central region gives a range of 170 - 220 days.The reason that kiln dried wood does not re-adsorb as much moisture (to a EMC level of wood air dried) has to do with the hysteresis isotherm sorption curves of wood; basically that energy is needed to break the chemical bond between wood and water for drying (you need energy input to get wood dry for interior uses) and that after the wood has been dried there is cross-linking of the cellulosic molecules that requires energy to break those bonds so as to provide a site for the vaporous water molecule to bond to. HOw's that for a run-on sentence????I never trust moisture meters -- they don't apply for wood above the fiber saturation point about 25% (that is when there is still free water in the lumens); and unless they are calibrated to the particular species in question will read differently. The only meters I trust are ones that I have compared with known moisture contents determined by oven drying. A funny meter improperly calibrated for the particular species being considered can be off by as much as 8 - 10%. I love to see guys use these things and go from walnut to oak to cedar measuring moisture content and actually believing the results they are obtaining. Di-electric constants are different for various species and these vary dependent on moisture content, wood density, acidity, grain orientation, etc., not to mention the penetration depth and the power of the battery.Texas A&M has a Forest Products Department and runs the Extension program for the state. In NY, contact SUNY at Syracuse.
*One of the truly great things about the internet is that we could be creating new standards. In the past, scientists worked in fairly isolated situations, devloped these hypothesies (sp?) and did their best to prove, and disprove them. Now, with the internet, we can pool our knowledge from real world trial and error, discuss what did or didn't happen, and I think new standards can emerge from these discussions. I really value all that government information and the scientific research behind it, but I trust my own experiences, and my ability to reason through problems at least as much. Keep posting what you believe, we all benefit from the exchange of thoughts.
*I believe........ that I would never want to argue anything with Stanley.Very impressive. But I am a Texas yahoo. I'm impressed with sliced bread and zippers.I nominate Stanley....... Honorary Valedictorian of our humble site.Three Cheers,Ed. Williams
*He sure sounds like he knows what he's doing.