by Eric Meier

Allowing lumber to passively sit at a given humidity level in order to obtain a desired EMC (air-drying) may be the simplest and least expensive method of seasoning wood, but it is also the very slowest. Drying times can vary significantly depending upon wood species, initial moisture level, lumber thickness, density, ambient conditions, and processing techniques.

Drying times and kilns

The traditional rule-of-thumb for air-drying lumber is to allow one year of drying time per inch of wood thickness; this adage obviously only takes a few of the aforementioned variables into account, but it’s at least a rough starting point in understanding the time investment required in order to properly air-dry lumber.

In situations where green wood is to be processed into usable boards, (especially in the case of thicker lumber), a kiln is frequently used to control the drying process. While there are various types of kilns used to dry lumber, the basic premise is usually the same: a large insulated chamber or room is used to balance and control humidity, temperature, and airflow to safely and efficiently bring wood down to an acceptable moisture content.

The main advantage of a kiln is that with the increased temperature and airflow—all while carefully maintaining and controlling the ambient humidity—the wood can be dried much more evenly, minimizing any sort of moisture gradient between the outer shell (which dries very quickly) and the inner core (which slowly equalizes moisture with the shell). Thus, a kiln is able to dry wood much more evenly, and it’s this uniformity in drying that allows it to also dry the wood quickly—simultaneously avoiding the drying defects usually associated with rapid, uneven drying.

Drying defects

But kiln drying may also introduce internal stresses into the wood—particularly if an improper kiln schedule is used, or if corrective measures are not employed—resulting in a condition known as case-hardening. This defect is caused when the outer shell begins to dry faster than the core: the shell tries to shrink, but is inhibited by the still-wet core. If the moisture difference between the core and the shell is too great, the shell can dry in a stretched condition. Later, as the core eventually begins to dry and shrink, the condition is reversed, and the stretched shell prohibits the core from completely shrinking. In extreme instances of case-hardening, the core can split and check in an irreversible condition called honeycombing.

This piece of Red Oak (Quercus rubra) exhibits honeycombing, which is among the worst of drying defects, both because it’s irreversible, and it usually can’t be detected by looking at the face of the lumber.

Kiln drying wood at elevated temperatures also has many other secondary effects as well, such as killing powderpost beetles (a destructive wood pest) in all stages of their development. However, it can also cause some woods—such as Black Walnut (Juglans nigra)—to lose the vibrancy of their heartwood colors, resulting in a more uniform and/or washed-out appearance.

For most woodworkers, running their own kiln to quickly dry lumber may be impractical or excessive. In most instances, simply storing project lumber at a targeted humidity level is the best option to ensure it will be at the correct EMC when building time comes. However, in some cases, such as when processing logs or other green wood into lumber, a more meticulous procedure will need to be followed.

Home air-drying tips

  • Process logs in a timely fashion. If a tree has just been cut down, or there has been recent storm damage, it’s best to process the logs into lumber as quickly as possible; doing so will help to open up the wood and aid in drying, which can prevent rot or stain from marring the wood. Bark on whole logs can act as a natural moisture-barrier, and if left unsawn, can contribute to fungal decay and deterioration in some species. A hallmark of poorly processed, do-it-yourself lumber is the presence of spalted or partially rotted wood.
  • Cut the wood slightly oversized. Remember that wood shrinks as it dries. This, along with the material that will inevitably be lost when the boards need to be jointed/planed smooth, mean that green wood should always be cut larger than the desired finished size. (And you usually don’t need to bother jointing/planing the wood prior to drying, since it will no doubt distort at least slightly during the drying process, and the edges should be dressed after the wood has dried to EMC—an exception to this is that two surfaces of a log should be jointed level to facilitate getting even and predictable cuts on the bandsaw.)
  • Seal the ends. In addition to processing logs in a timely manner to prevent stain and decay due to excessive moisture, the opposite is also to be avoided: allowing the wood to dry out too quickly will result in splits and endgrain checking. It is important to remember that moisture escapes from wood about 10 to 12 times faster on the ends than through other surfaces. Sealing the endgrain forces the moisture to exit in a slower, more uniform manner. If this is neglected, the ends will tend to shrink faster than the rest of the wood, creating tremendous stresses on the piece that’s ultimately only relieved with endgrain checks—a very common drying defect. (Although there are specially formulated endgrain sealers on the market, just about anything will do in a pinch: paraffin wax, polyurethane, shellac, or even latex paint can be used to seal the endgrain surface. The key is to build up a thick, obstructing film that will inhibit moisture from escaping at the ends of the board. In order to minimize the risk of checking, it is best practice to coat lumber ends within minutes—not hours or days—after coming off the saw.
  • Stack and sticker. Having lumber of uniform lengths and thicknesses greatly aids and simplifies the stacking process; once a log is sawn up into planks of satisfactory dimensions, it’s crucial to stack them in such a way that they will be exposed to air on all sides—stickers are typically used for such a task. Stickers are small pieces of wood (usually about 3/4” x 11/2”) that are used to add space between sawn planks, which increases ventilation and aids in a more uniform drying process. Sticker spacing varies depending on the species and thickness of the lumber being dried; a conservative spacing scheme would be every 12”, though usually 16” or 24” spacing can be safely used on thicker pieces.
  • Add weight. Once the stack of wood is stacked and stickered properly, it’s helpful to add weight to the stack. The lumber at the bottom of the stack is probably weighed down sufficiently by the wood on top of it, but boards near the top greatly benefit from added weight. Weighing the stack of wood down helps to prevent warping or distortion, which is especially important during the initial drying phase when going from green to an ambient EMC. Neatly and properly stacking, stickering, and weighing wood will go a long way towards ensuring that the drying process will result in flat, stable, and usable lumber.
This small stack of Buckthorn (Rhamnus cathartica) half-logs has just been cut, stacked, stickered, and sealed with a water-based wax emulsion coating.

This small stack of Buckthorn (Rhamnus cathartica) half-logs has just been cut, stacked, stickered, and sealed with a water-based wax emulsion coating.

  • Add heat once EMC is reached. It’s important not to rush the drying process too quickly, but once a wood pile has safely reached EMC, it may be necessary (especially during humid summer months) to bring the MC down even further for a specific project. This can be as simple as moving the lumber stack from a garage or shed into a heated basement indoors. In cases where shorter pieces are used, a drying cabinet can be used to gradually reduce the MC down to 12% mc, 6% mc, or any other level that an application may call for.

A drying cabinet can be nothing more than a simple wood cabinet with an incandescent lightbulb on a dimmer to finely control the light output—which in turn dictates both internal temperature and consequently relative humidity. Many thermometers (both traditional and digital) sold by big-box retailers also feature a hygrometer with a somewhat accurate readout of the relative humidity; the ability to know the rh of both the drying cabinet and the wood shop proves to be a helpful and prudent investment.

Warp and distortion

When a wood species has a high T/R ratio, it will tend to shrink in one dimension more than another while drying, causing distortion or warp. A good way to visualize the tendencies of wood during drying and shrinking is to picture the arc of the growth rings trying to flatten themselves out. (This of course is not actually the cause of the shrinkage, but it serves as a good memory tool to help visualize dimensional changes.)

This endgrain view of Plum exhibits cupping. The board was initially cut flat, with the top and bottom originally being parallel. Further machining will be necessary to ensure the board is flat and square.

This endgrain view of Plum exhibits cupping. The board was initially cut flat, with the top and bottom originally being parallel. Further machining will be necessary to ensure the board is flat and square.

The results of uneven shrinkage vary depending upon the particular shape and grain orientation of the board; flatsawn boards become cupped, riftsawn square stock becomes diamond-shaped, and circular dowels become ovoid.

Additionally, there are a number of warping issues that can occur which are not solely related to uneven shrinkage. In certain cases, a pre-existing flaw is present in the wood itself, which is only brought out and made apparent by the drying process. This can result in defects such as: bow, crook, twist, or a combination of two or more defects simultaneously.

Regardless of the specific names that can be applied to distorted lumber, most drying-related warping issues can at least be minimized using a few simple guidelines:

  • Use proper stacking techniques. As mentioned previously, by far the most important deterrent to warp is the adequate stacking, stickering, and weighing of a lumber stack.
  • Avoid juvenile wood. Juvenile wood is wood that is formed during a tree’s early years of growth, and can be thought of as an extension of the pith. There is no officially determined width of juvenile wood, (usually excluding the first few central growth rings is sufficient), but generally, the further the wood is cut from the pith, the better. Much like the pith itself, juvenile wood is very unstable, and has an elevated rate of longitudinal shrinkage; this increased shrinkage rate pulls against the mature wood and causes it to contract and deform either along the face of the board (bow), or along the side of the board (crook).
  • Avoid processing branches or leaning trees. Wood that has been growing at a slant doesn’t have uniform growth ring spacing and varies from the topside to the underside. This abnormal wood is called reaction wood, and it can cause a number of unpredictable warping problems during drying. In softwoods, reaction wood forms on the underside of a branch or trunk, and is called compression wood. Conversely, in hardwoods, just the opposite is true: its reaction wood forms on the topside and is called tension wood.
  • Avoid knots. Simply put, knots are sections in the trunk where limbs once grew. In addition to shrinking unevenly or possibly coming loose during drying, (leaving a knothole), knots can also create areas of concentrated abnormalities in the wood grain, and consequently impact its shrinkage properties. The presence of large knots can result in dramatic and exaggerated warp during drying.
  • Handle spiral or interlocked grain with care. Some wood species have what is called spiral or interlocked grain. Just as the name implies, the wood fibers grow in a twisted or interlocking manner. Not surprisingly, this can result in drying problems, most commonly twist—where one of the corners of a board is raised up out of the plane of the other three corners. Careful drying, along with proper stacking, stickering, and weighing can help alleviate difficulties caused by irregular or spiral grain.

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  • suegatmarois

    The article is clear and concise. I didn’t read this article soon enough. I didn’t seal the ends of my lumber but I will definitely weigh the lumber down.

  • Donna

    I tried beeswax on end grain, but it interfered with finishing and I had to cut off impregnated wood. I decided that sawing off the part of the end grain that has the fast drying cracks was better because I would have to saw off that part anyway if it had the end grain sealer in it. However, it is a question as to how much has to be sawn off to remove the sealer impregnated end, or remove the unsealed cracked end grain.

    • ejmeier

      I’m not sure how far the wax seeped into your wood, but in my experience, it’s maybe 1/4″ at the most. Just about anything will require you to trim at least a little bit off the ends. Beeswax seems like it would be incredibly expensive! You’d be better off just slopping leftover paint on the ends with a brush. (No, honestly, thick coats of paint will do a great job at sealing the endgrain.)

      Depending on the wood species, if you don’t seal the ends you could easily lose several inches off the ends, or possibly have it check along the entire length of the board. I’d guess that in all but a few select circumstances you’d end up with more usable wood through sealing.

      • Tom Zawila

        titebond white glue works really well and does not stain as easily. Wax will tend to fall off as the wood shrinks, (by experience). Anchor seal is ok but is not always available and can stain more readily. Good Luck!

  • PVA wood glue is also a good endgrain sealer. Apply 2 coats and it seems to be working fine on some wood I’m drying for turning. I left 1 small piece unsealed for comparison & this has cracked considerably.

  • _GA3FAR_

    I’m fairly new to this, but If I am to make a drying cabinet like the last paragraph suggests; how long would it take to dry the wood from 12% to 6%?

    • blackbeered

      forever

    • kedwa30

      The answer to ‘how long’ would still depend on the many other factors: How warm does it get inside the cabinet? What species or density of wood? How big is the piece of wood? What is the humidity outside the cabinet (thus how humid the air coming into the cabinet)?

      I have had success taking wood down to 6% in mere minutes by microwaving very small pieces of oak in the kitchen microwave a few pieces at a time (a lot of trial and error getting the timing/settings just right for my wattage of oven [of course the microwave heats the water on the inside and you then set the wood outside the oven to dry while you heat the next batch; test and repeat until you get it]).

      If your cabinet is air-tight, you will never lose any moisture, so if you utilize a cabinet originally designed for food storage, be sure to cut a hole in the top and bottom to allow air to pass through. Make slider doors over the holes to allow you to adjust or damp the amount of air flow. You could use a micro-controller with temp and humidity sensors to control the heat and the air flow. I think the core temperature of the piece being dried has a lot to do with how fast it dries. Get your cabinet temp up to 120F and it will dry quickly, in a matter of days. It’s like an easy bake oven.

    • Julia Xia

      a new technology called high frequency vacuum wood dryer,from 12% to 6%,for mid density wood,1~2days is ok,if you are interested,inform me sagahf2@163.com

    • Julia Xia

      with high frequency vacuum wood dryer,about 2 days.More detail you can email sagahf2@163.com

  • Rapscalion

    This article has answered many of my questions concerning lumber, but i still have a remaining question. What if i want to dry/cure a thin round or cross section from a large diameter tree for the purpose of making a decorative table or clock. Obviously this means the majority of surface area is end grain. Do i still seal it with something, and does that mean that i should cut my round 1/2” to 1” thicker than what the finished thickness will be after it goes through the planer in order to remove the sealer(after curing) for staining purposes?

    • ejmeier

      Endgrain cross sections are notorious for splitting or checking, and the bigger the diameter, the more likely it is to split.

      Certain species (Laburnum, Olive, and others) are known to be resistant to splitting. Regardless, I wouldn’t put a sealer on while it’s drying. If I were you, I’d put it inside a brown paper bag, and then put that inside another brown paper bag, stapled or taped shut. This should help regulate and slow the drying process. (BTW, you can’t/shouldn’t plane endgrain.)

      • jon

        ok….ive got green hackberry logs 50 inches thick and 12 feet long….so are you saying they wont check if i dont coat them? where can i get a brown paper bag that large?

        • ejmeier

          My previous reply was in the context of a (relatively) thin piece of wood — in this case, an round endgrain slice. The paper bag technique is used by turners who have already rough-turned their projects down to about 1/2″ to 1″ wall thickness.

          In your circumstance, you’d need to seal the logs. I’m not sure if you’re planning on using the logs whole, or if you’re going to cut them up into smaller pieces, but conventional drying wisdom says to slab/cut the log FIRST, and then dry it. Things will be much easier and faster this way.

    • kedwa30

      Something you could try, and I’m just throwing this out there, is gluing it to a sheet of plywood. In theory, this will hold it in place so that it will dry without warping. I would keep moist towels on the unglued side at least until the glue cured. If it’s too thick, it will check on the unglued side anyway, in which case you might try gluing plywood to both sides until it dries.

  • Don

    great article, as “suegatmarois” stated, clear and concise. thank you.

  • jon

    use polyurethane floor sealer, as soon as the wood is cut….hours, better than days after the saw leaves the wood….keep it out of the sun, and wait 2 years…..if you saw logs then get 3 slabs from a log, and good luck……some folks actually soak it in salt water and vinegar for 5 years, and they say when they let it dry, it never checks….kinda like logs in the great lakes, or ocean…

    • Chris

      I find if I leave my logs for the length of time you suggest I find they have been attacked by woodworm. I have also found turning green wood is a waste of time due to twisting and splitting. I get dispondant after turning a bowl for example a split appears either as I am putting the finishing touches or the following day.

      • ejmeier

        Not sure what your procedure is, but generally turning green wood is done in two phases: first a bowl is rough turned to approximate shape, leaving 1/2″ to 1″ wall thickness (more or less depending on overall size). Then the rough blanks are allowed to dry (I put mine in a closed brown paper grocery bag). After the initial drying and slight deformation occurs, the bowl is put back on the lathe for the final turning, sanding, and finishing. Turning a bowl from green to finished product in one shot is asking for disappointment!

  • Old guy in the woods

    One of the last items on my bucket list, is to build a small log cabin, from planted pines, on our property. They are about 8″ diameter. I am 71 so need a quicker solution. What happens if I cut the trees, strip the bark and build the 20′ x30′ cabin in the woods. I have in mind to have the top and bottom, of the logs cut off, leaving a sort-of oblong shape. I intend to have vertical all-thread rod tying the logs together on 4′-6′ centers, so I can tighten nuts on large washers as wood shrinks. Someone told me the frontier folks, cut the trees and built the cabin at the same time.

    • gregor

      you can build with wet logs they will shrink and check naturally don’t worry about it

    • gregor

      Timber frame homes are also built with wet lumber I worked in a timber frame home plant. we cut all the tennons mortises and dove tails and build all trusses from wet lumber.

      • Al

        Thx Gregor I’m going to start cutting trees. Need to anyway to make room for goats. LOL

    • rsolid

      It is done with wet lumber all the time in Alaska with trees cut processed and used days apart. What you do is set your doors , windows , any opening on a metal case. Leave room (about an inch) all around the metal casing so you rough cut openings will be two inches higher and wider than the window size. You hide the gap with 1×4 trim and when the wood shrinks , your doors will still open and your windows will work. I hope you complete your project and enjoy it soon !

      • Gordon Hirt

        An inch may be OK on the sides of doors and windows but we left a LOT above doors and windows. Green logs can shrink 6-8″ per tall floor depending on the log assembly style (T&G, swedish cope, etc)

    • Chick from the Sticks

      Built a cabin with green logs, pine from my property. Logs were 10″ diameter. Left a good amount of the brownish layer under the bark(I forget what it’s called). Trees were cut in early fall after the weather had cooled a bit and the cabin walls were up by snowfall in November! That was almost 14 years ago. No rot. Some checking for sure, but expected it and it only adds to the rustic charm :) Go for it Old Guy in the Woods!!!

  • Deluch

    Crazy question but does anyone know the drying time for western red cedar logs, could they be placed in a solar kiln to dry quicker (a big kiln for 10 – 15 logs @ 12-15 inch dia.)? I also hope to build a log home in the next 2 years and have started to research the process from tree to wall…any help would be great.

  • ejmeier

    Round endgrain slices, no matter how slowly they’re dried, have inherent stresses within them. The wood wants to shrink about twice as much tangentially (parallel to the growth rings) than radially (from the center of the disc outward). So being a whole circle without relieving any of the stress is asking for trouble and prevents the natural shrinkage from occurring. A pie-shaped wedge may open up in the endgrain disc, and the larger the diameter of the disc, the more likely and more dramatic will be the split.

  • tikotongos

    i am new in the topic and i would like to know why when i cut my 2′ thick and 5′ width iroko board in 1/2 thick stripes on the bandsaw, the stripes shrink alot. The board is 50′ long! Moisture is about 10%. For me the wood is now useless!!! Can somebody explain me this??? Did i do something wrong or i just didnt choose the correct lumber of iroko??

    • ejmeier

      I’m not clear on the dimensions of your lumber, using the single ‘ denotes feet, not inches. Inches are designed by a double “. I’m guessing you mean you have a board that is 50 inches long, and not 50 feet long.

      There’s a lot of reasons why you could be having trouble. What exactly do you mean by “shrinks alot”? If it really is shrinking, I’d guess the wood is not totally dry. But if it is warping or twisting somehow, then that’s another story.

  • Phillip

    I have some sawed cherry lumber that’s been in the barn for 10 years. 1×4’s to 1×8’s. Wanted to use them for flooring but a friend of mine said they’re not dry enough and would warp after planing.
    They’ve been through Mississippi summers and I’m wondering if he knows what he’s talking about. Anyone?

    • ejmeier

      How were the boards stored? More than likely, they’ve reached equilibrium moisture content. If you wanted to use them for flooring, I’d recommend storing them inside for a while before you install them. This will allow the wood to acclimate to the humidity level INSIDE your home rather than out in a barn.

      • Phillip

        Stacked and stickered. My dad had them sawed after Hurricane Katrina blew them over.
        Are you saying plane them then store them inside?

        • Jon

          Yes that will work. Ten years should be plenty of time for them to dry. I would invest in a moisture meter. I would not use the lumber until it has reached a 10% moisture content. This can be more or less depending on the relative humidity of an area. But after 10 years it will not be drying any further by air drying. I think it will be perfectly fine to use now. Generally wood is air dried for about 1 year per inch of thickness. Then planed and checked for moisture content. Cut an inch or two off the end of the board before checking the moisture content.

      • Phillip

        They were stacked and stickered. Good ventilation I assume.
        After they’re planed what would be some things I might encounter? Not a real big woodworker. I prefer metal, you can always add more!

  • terry

    Maybe this is a dumb question, but I plan on building an addition next year, so I have about 12 months between now and when I will be doing the framing. If I were to buy the lumber (2×6’s etc) from the yard now and stack it and sticker it and leave it under cover (in my barn) for that year, will it prevent some of the problems with warping you typically get from typical Home Depot (or wherever) lumber? I’m in Ontario, so humid summers and cold winters, which the stack would experience. I know lumber quality seems to be lower these days, so I was hoping to mitigate that through some prevention, if possible.

    • ejmeier

      Probably couldn’t hurt. Not 100% sure though: maybe the distortion is caused by knots/defects in the wood itself…

    • kedwa30

      I think the best thing you can do is paint every board with a clay mixture known as whitewash. There are different things that have come to be known as whitewash; I’m talking about a clay mixture.

  • Jesse Francis

    Exactly what is a “water based wax emulsion” and under what product name(s) may I find it? I can only find floor sealers and the like, nothing as thick or opaque as pictured above.

  • andrew

    so i have cedar in my woods that has been laying there almost 30 years (when they cleared the property to biuld the house) can i just get this and start making stuff with it?

    • ejmeier

      Are you talking about cedar lumber, or just a raw cedar log? 30 years is a long time… I would take a look at it first and see what kind of condition it’s in. If nothing else, you’d probably want to let it air dry and let the moisture level even out across the length and width of the board(s).

    • kedwa30

      Yes, there is some very pretty wood inside just waiting for you to clean it up. To some people, it’s only good for a fence post, but if you are making small parts, there is plenty of beautiful red/pink wood inside those old grey logs.

  • Lynn Hopkins

    We recently had a major storm and I’m now the proud owner of maple and oak (some white pine) logs. I will be having them cut into boards and will be drying them outside. I’ve been cautioned about powderpost beetles. What do I need to do to avoid damage from insects? I’m a newbie.

    • ejmeier

      To an extent, air-drying lumber can be a roll of the dice. While I can’t speak for others, I’ve had good results with no issues, and the only time I’ve had an infestation was with some ash I was drying.

      If you’re worried about powder post beetles, you could use a pesticide in lieu of kiln drying the lumber. A product such as Tim-bor can be brushed or sprayed onto wood surfaces to protect them. http://www.amazon.com/gp/product/B00282L6T2/&tag=thewoodat-20

  • Sam Ryan

    I am making a reclaimed pine rustic table top for a client. I bough the pine from a reclaimed timber yard and the wood was left outside so the planks were wet. They were 31 mm x 250 mm wide and 2 metre’s long. I have over the course of a week left the wood in my house to dry enough so it is damp and not wet. I have plained the wood to 25mm thick over 4 days to allow movement. My problem is that the wood is still slightly damp but a lot better. As I am making the table top for a client, they will want it back in a few week. My big question is how dry does the wood need to be and how long is a short but suitable time to dry enough to put a finish on it and give it to the client. I need help with this please.

    • kedwa30

      I see that this post is two months old at the time I’m posting this, so I’m wondering how things turned out for you.
      As you hopefully found out before now, the answer to the question of how dry wood should be depends on the humidity of the air in which it will stay, but generally under 7%. If you coat only one side and then put the table in a dry home, the uncoated underside will dry out before the coated top side and this can result in warping and cracking.
      If the wood feels damp, then I consider it too wet to coat, but it really depends on what you are coating it with. If you get the water content down to some percentage as measured by a probe and it feels dry to the touch, you can seal it on all sides and then it shouldn’t matter how much water is in the wood since it will be sealed in. You also want to avoid over drying or drying too fast. The way to determine water content is usually by jamming an electronic probe into the side of the board on an inconspicuous surface, but if you know how much your wood should weigh dry versus wet then you can determine water content by weighing it. I suppose that tip is more useful for people using very small pieces of wood who don’t want any surface marred by test probes.

    • Julia Xia

      do you know high frequency vacuum wood dryer?For your pine wood 25mm thickness,from MC 40% to 8%,drying time is about 4 days.More details you can email to sagahf2@163.com

  • Paul Viekman Sr.

    Does anyone know how much weight is sufficient to prevent twisting? I usually place 3 to 4 cement blocks (8x8x16″) over each set of stickes spaced at 24″, (stacked 24″ and 36″ wide) with a couple of extra at the ends if I have them, and have had good luck, but I am running low on blocks. I have a bit of Eastern White Cedar that I have just sawed out. I am thinking about a 5 gallon bucket of sand on each set of stickers. Any idea if that should be enough?

  • angry_professor

    I love wood. I do abstract and figurative carving and assemblages, build furniture etc. My neighbor had to have a large “peppermint” eucalyptus taken down. The few chunks I rescued include rounds to sections with some bark to large near cubes 20″ on a side. They are an amazing orange color, extremely dense, wet and heavy. I’d like to dry them slowly to minimize checking so they can be carved. Please, beyond painting the end grain (with the vertical grain exposed or not?) can anyone suggest the proper drying method? Thanks much.

    • Julia Xia

      high frequency vacuum drying is the best.HF only acts on the moisture of wood,where there is water,there is HF.So drying wood from inside to outside.The wood is uniform dry from surface to core.You will not have problems when carving.More details you can email to sagahf2@163.com

  • Fred III

    I was wondering, can I use interior paint to seal the ends of split logs? I have a large walnut tree that fell in a storm and after around a year took a firewood sized log, split it, let it sit for a few days and finally coated the ends with interior white paint. Just what I had in the house. There are some cracks already up to an inch in that appeared after painting. Is it cracking simply because I did not get it painted right after cutting? The cracks only appear to be in the sapwood. Also, there is a vein type line going all the way down the halves in the center. There are perpendicular cells all the way up it, and in between those, it is hollow. It is only about 3/16 at widest… Not to worried about it but was just wondering.

    • ejmeier

      I’ve found that walnut sapwood can be tricky (and most sapwood in general tends to be less stable than the heartwood). Also, sometimes coating the ends isn’t enough if the environment where they’re being kept is very dry or there is a lot of air movement.

  • Ickhyung Eom

    Thank you, Eric Meier.
    I know EMC concept and i have to dry some wood at 8% MC. but i don’t have data about EMC regarding several types of wood.
    If you have some data for example oak, cherry, maple, teak, merbau and so on, please email me eih0713@nate.com
    thank you!

    • Julia Xia

      I have sent you an email,please check

  • ejmeier

    I think the single biggest help would simply be to know what the MC the wood is currently at. Beyond this, as a general rule, I’d recommend starting outdoors and moving indoors after several months — it all depends on what the MC of the wood is at. Tarps aren’t ideal, but yeah, you should try to keep it somewhat protected from the elements — direct sunlight as much as rain.

  • Brad Schutz

    I am considering making a kiln out of a 20 or 40 foot metal shipping container. The air would circulate through two holes (front/back), with ability to treat air for temperature and humidity prior to entry. Could also add dehumidifier/humidifier internally with a bottom drain. My vision would be to recover newly downed trees, put them through a de-barking and a bandsaw to cut thick boards, paint ends, then stack in the container with spacers and weight on top to deter warping. First process would be to keep humidity above 25% and heat to 150 degrees for a week or so to kill off any bugs. Next is to drop humidity and keep boards at about 90 degrees until an internal MC is reached. Question: How does one check internal MC? I realize that the drying time would depend on the thickness of the boards and the type of wood and original MC, but lets suppose I start with loblolly pine, 2 x 6, initial MC at 20%, what would I be looking at for a drying time?

    • Julia Xia

      for pine wood,if you use high frequency vacuum wood dryer,from MC 20% to 8%,2′ thickness,drying time is 3 days.High frequency drying wood from inside to outside,only acts on water,more fast and uniform.Will bring you a perfect drying result with no bending,cracking,color changing.More you can email me sagahf2@163.com

  • Richard Karon

    Hello, I have begun to clear about a 1/2 acre of Eastern White Cedar in Southern Ontario. My plan is to mill the trees into 1″ thick boards to use as board and batten. My intention is to stack the trees over the winter before milling them in the spring (March/April). From what I have read of EWC it can be used within a month of being milled for outdoor applications such as board and batten due to its low shrinkage and warping. Is there any truth in that? Thank you.

  • Richard Karon

    Hello, I have begun to clear about a 1/2 acre of Eastern White Cedar in Southern Ontario. My plan is to mill the trees into 1″ thick boards to use as board and batten. My intention is to stack the trees over the winter before milling them in the spring (March/April). From what I have read of EWC it can be used within a month of being milled for outdoor applications such as board and batten due to its low shrinkage and warping. Is there any truth in that? Thank you. rk

    • Julia Xia

      if you use high frequency vacuum wood dryer,it will be fast.2-7 days

  • Stephanie

    My parents just topped their leaning cedar. I can’t find the real name for it- it looks like a tree out of Dr. Seuss. Tall, curvy and leaning. I did get a straight section that I wanted to slice into 1/2-1 inch thick pieces. It’s probably 8-10″ across. I was thinking about cutting on a diagonal to get a more oval shape. I want to paint a jumping fish one side with acrylic then seal.

    If I paint now and give as a gift, just sealing one side and leaving the other exposed to air will it be ok to finish drying out over time? Any concerns I should have about leaving the bark on? Any special sealer for that?

    Also, they have some other pieces that are very dark in the center so I didn’t take them. Is this from sap? if I slice off a fresh section and treat with knotting solution would that help?

    Thanks for helping a novice like me!

    • ejmeier

      It sounds like you are taking endgrain slices of the trunk, rather than cutting lumber down the length of the grain.

      I don’t have much experience with this, but the risk for cracking and splitting endgrain slices is much, much higher than regular boards, so proceed with caution.

      • Stephanie

        Thanks! You are correct, I’m taking slices from the trunk. The tree is a weeping cedar.

        • kedwa30

          It’s my understanding that the reason wood is dried is to see where it cracks so you can work around that. I’ve been working with Eastern Red Cedar, and it always cracks unless I split it, and then it warps. Its shrinkage is not as bad as the oak I’ve worked with, but IMHO, cracks are inevitable and you should split it if you are going to let it dry, or you should seal both sides so that it never dries.

        • ejmeier

          Even with both sides sealed, the wood will eventually dry, it just might take years instead of weeks.

          For whole round endgrain slices, the way the wood wants to shrink (about twice as much tangentially with the rings as compared to perpendicularly), there’s a lot of internal stresses built up within the wood that makes using this type of cut difficult. About the only rule of thumb I’ve heard that can help is to keep the overall diameter of the log to be dried as small as possible.

          Bruce Hoadley has a demostration in one of his books on this, where he takes a flat endgrain disc and saws a tiny slit from the edge to the center of the slice. As it dries, it opens up like a slice of pie and almost looks like Pac Man. In contrast, the wood that wasn’t sawed developed all sorts of checks and splits in the disc and was more or less unusable.

  • Julia Xia

    how about the thickness?If dry with HF vacuum wood dryer,from MC 40% to 8%,50 mm thickness,the drying time is about 4 days.More details you can send to sagahf2@163.com

  • Julia Xia

    with high frequency vacuum wood dryer,for your red cedar 2″ thickness,from MC 40% to 8%,drying time is about 3-4 days.The whole drying process id fully automatic.More details you can email to sagahf2@163.com

  • Barry Keith

    I want to make a dinning table out of Black Oak trees that were cut down. Finding a Kiln in my area is a little difficult. I saw a video on YouTube about a solar kiln with rolled plastic. It sounded like a great plan just wanting to know if anyone had tried this and how long that takes to dry the lumber.

  • DO-NOT-MESS_with_USa

    Other than cracking, what would I expect in over drying (mainly) cedar and other light weight woods?
    Will this cracking still occur in 1″x2″ and 1″x3″ boards?
    I’m looking to get this wood light as possible, color means nothing.
    THANKS
    (email me if there’s a post) moc.asu@mvf

    • ejmeier

      If done properly, not much would happen. Is there a particular reason that you want it to be as light as possible? If you are drying it in a kiln or some other controlled environment, as soon as you remove it and put it into the real world, the wood will regain moisture fairly rapidly (especially in the smaller sizes that you list) and regain its weight according to the relative humidity where the wood is stored.

  • Left Blank

    I just picked up some Bodark logs from a neighbor that I will want to use in future for making a jointers mallet head. As the above states, I use poly to coat the ends as this is all I have, no other waxes currently. Should I remove the bark in order to dry? Also, should I keep as large log for drying or should I chop up?

  • Koen Gabriels

    Hi, I cut down a young oak tree yesterday in my backyard, the trunk is about 3 inches at the bottom and tapering down to about 2 inches over the length I want to work with.
    I plan to try and cut a sort of decorated staff out of it to use for hiking. (the will be slimmed down quite a bit but I need the “big” diameter because in parts the final result should be that wide)

    This three was slanting and I am now wondering if it makes sense to get it in a kiln (I found a wood supplier locally that have kilns) or maybe it doesn’t need to dry for that long by just air drying it?

    I am completely new to this so sorry if I am asking dumb questions, the reason why I suspect I don’t need to dry it that long is because I read in the comments that using logs to build cabins can be processed while wet.
    Am I right in thinking this?
    The staff could be stored safely outside so it only “lives” outdoors :)

    Thanks for any help or suggestions

  • Kyle Watson

    I have oak that isn’t green so seems really dry. I have a baby die in 3 1/2 months and my wife pressured me to just lay it now on the bedroom floor. It’s 1″ thick oak. I haven’t polyurethane it yet, I’m waiting another two months to sand and poly it. How much shrinkage should I expect?

    • ejmeier

      Depending on how much money you have tied up in this project, I would strongly recommend just getting yourself a moisture meter and testing the MC of the wood. Oak has a lot of shrinkage, so a miscalculation here could be costly.

      PS – hopefully you have a baby “DUE” and not “die” =O

  • ejmeier

    To be honest, the larger diameter of trunk that is being dried, the more likely it is to crack or check. Also, the faster it dries, the more likely to check. If you are absolutely set on using large diameter endgrain discs, and it just has to survive for one single day (the wedding day), you may consider timing things so that it will look best for that day only. Long term, I see these types of projects as a ticking time bomb in terms of stability and risk for splitting.