Bought wet timber – how long to dry?
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28 July 2016 at 11:24 am #138881
I just found a business close to my house that saws up timber, and bought five pieces of poplar 20x130x1250mm for the equivalent of about $1 each. They are soaking wet though, having just been sawn from the log.
My question is how long before they are usable? It is 32*C here in Bulgaria, and dry as a bone. I have put them inside the house out of direct sunlight and separated them to maximise the surface area. Is there anything I should (or shouldn’t) do to prevent them warping, or is this just luck of the draw?
The same business also had an old well-seasoned walnut trunk that could be sawn to any specifications the customer wants. Being new to woodworking with hand tools, I don’t think I’m ready to start butchering walnut just yet, but it was interesting to see it all the same.
This raises another question. Is it better to saw the wet wood and then allow the planks to dry, or allow the whole trunk to dry and then saw it into planks? If I had to guess, I’d say the latter was preferable, but will take much longer.
Steve, the rule of thumb around here (U.S.) is 1 year per inch (25 mm) of board thickness.
(the following is from the wood database website: http://www.wood-database.com/wood-articles/drying-wood-at-home/
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.
28 July 2016 at 12:55 pm #138897Thank you. That is exactly the information I was looking for, although I was hoping the answer wouldn’t be to season it for a year!
I have noticed the ends of the boards are already beginning to split. Would putting some linseed oil on the endgrain help? I have linseed oil, but not any of the other substances mentioned. Finding specialist things in this country is not easy, especially with no grasp of the language (yet), so using what I have would be an advantage.
Since I’m only $5 in, I’m happy to treat this as a learning experience.
28 July 2016 at 1:10 pm #138898I don’t think linseed oil would do the job, but you can seal the ends of the board with ordinary latex paint.
30 August 2016 at 9:54 pm #139801As you seem to be a bit short on money, how about candle wax? Perhaps even plastic wrap is better than nothing. I am just guessing here…
I would not use linseed oil for its self-combustion properties. It might be safe inside the wood, but better don’t find out, if it is not. I think, most hard curing oils have the same problem. Mineral oils are safe, I think.
31 August 2016 at 3:02 am #139806I don’t think oil would work because you need a good moisture barrier. Paraffin (canning) wax or candle wax would work. I’ve used old paint as well.
10 September 2016 at 2:25 am #140033You may want to look for European standards.
In the US, we apparently dry wood to about half the moisture content (say under 10% rather 20%) as compared to Europe. This is apparently done because, as a whole, we have a drier environment.
It has been suggested to me that, because most of the world cures to European standards, the better US importers go though a 2nd cycle of air and kiln drying when their wood arrives.
Net of this, I’m wondering if you need the same number of years per inch to hit appropriate levels of dryness in your local.
Hope his is helpful.
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