Working with greenwood

 

Wood, especially interesting wood is expensive if bought already dry.

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Allowing cheap or free green wood to dry in ones own shed is the cheapest way of seasoning wood, but it is also the very slowest. Drying times can vary significantly depending upon wood species, initial moisture level, wood thickness, density, ambient conditions, and processing techniques. The time scales can extend into years. A rule-of-thumb for air-drying wood is to allow one year of drying time per inch of wood thickness and this gives one of the first techniques to speed up the process and avoid cracking.

 

Part turning a piece and then sealing it in a plastic bag with woodshavings allows the wood to dry relatively evenly and quickly.  Opening and turning the bag inside out occasionally releases some of the moisture.  I tend to weigh the wood at intervals and when the weight starts to be stable over a few weeks you know it is dry (or at least as dry as the environment it is stored in) so you can rechuck and finish. You may find that the shape will have distorted slightly – hence the need to leave the wall thick.

 

To track the drying I weigh the bag every week or two and when the weight reaches a plateau then you can be sure it is as dry as the environment you are working in. You will find that the wood warps of course - hence only part turning to allow the warping to be turned out.

 

Alternative turn down to the right thickness and let the warping add interesting dimensions to the piece but don't expect to be able to remount it and turn it again.

 

Kilns can be used and 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. Kiln drying can also help to get rid of pests but kiln drying may be out of the reach of hobby woodworkers and air drying might be the best solution.

 

Air-drying at home:

 

Process logs as quickly as possible; doing so will help to open up the wood and aid in drying.

Be aware that spalting is a fungus and the dust should be avoided - another benefit of kiln dried is that it destroys the fungus and stops any further rotting.

Seal the ends with wax or similarSealing the end grain slows down this moisture loss. If this is not done, the ends will shrink faster than the rest of the wood, creating stresses on the piece that’s ultimately only relieved with checks in the end grain —a very common defect.

 

Useful links

 

http://www.peterchild.co.uk/info1/green.htm

http://www.woodturningvideosplus.com/air -drying-wood.html"