Wood Drying

[Greg Newell]

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Ron,
         I would certainly be interested in any pictures you might care to=
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send along. Thanks in advance!

Greg Newell




At 04:49 PM 3/25/2003, you wrote:

>>Terry,
>>
>>Your most immediate danger is too rapid drying through the end grain.  THe
>>dimensioinal change from differential drying through the end can create
>>checking that will make large sections of wood unusable.  Don't waste a
>>second getting some form of moisture-impervious sealant into the end of
>>every piece.  Melted parafin wax works best, IMHO.
>
>Or, if you have any wood glue (out of date Titebond or rubbish PVA) lying=
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>about, that works very well also. When sourcing local logs, we specify=20
>that the log is end-sealed as soon as it is cut.
>
>Your idea of breaking the log down into 1/2" boards is a good one. Such=20
>boards will be ready to use in one year with just air drying (ie. for the=
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>panel, rib stock will take at least two years, unless you plan to make=20
>laminated ribs out of the 1/2" boards). When we break down a log for sound=
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>board material, after the large boards (2" thick) have been cut out, we=20
>break down all the small triangular flitchs into 1/2" wide boards, so as=20
>to obtain the maximum of useable spruce from the log (you will need a=20
>resaw with a tilting table for this purpose). The danger with drying is=20
>moisture gradients. Therefore, the thinner cut boards will tend to have=20
>less of a gradient problem, but they will be more prone to warpage. As=20
>soon as you have cut your boards, they should be stacked with spacing=20
>sticks (of say 25 mm by 25 mm section) between each layer of boards,=20
>spaced at about 300 mm (1') for boards 1" or thicker. I would recommend=20
>that the spacing sticks be set somewhat closer together for 1/2" boards to=
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>reduce warpage. The entire stack should be covered with some kind of=20
>roofing material and weighted on top (house bricks will do) to ensure that=
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>the upper boards in the stack are held down to prevent them from warping.=
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>Don't make the stack too high or the overall weight will cause the lower=20
>boards to sustain crush damage adjacent to the spacer sticks.
>
>I'll photograph the drying stack I have at the house and send you a jpeg.=
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>Looking at your location Terry (27 degress N, - I notice that you have=20
>another Sydney a few miles east), I would recommend that you commence the=
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>drying process during the winter months, since the summer heat will be=20
>very risky for freshly sawn boards. It is the initial drying phase during=
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>which degrade from moisture gradients is more likely to occur.=20
>Furthermore, quarter cut boards will tend to lose moisture faster through=
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>the edge of the board compared to the quartered face. This will occur with=
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>a quarter cut board since the medullary rays will be perpendicular to the=
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>edge and parallel to the board face. We seal the edges of quarter cut=20
>boards as soon as they come off the saw. This will greatly reduce the risk=
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>of stress damage at the edge of a quarter cut board during the drying=20
>process. I have noticed a tendency for belly wood to be more prone to=20
>compression set damage adjacent to the board joints. While there may be a=
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>multitude of reasons why this might be so, I have long suspected that the=
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>tendency for quarter cut boards to lose moisture faster through the edge,=
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>particularly during the initial drying phase, to be a factor here.
>
>By the way folks, our new sound board conditioning box is coming along=20
>nicely (the new box is big enough to accommodate a B=F6sendorfer Imperial=
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>board). If anyone is interested I'll be taking a photo of the assembly=20
>prior to fixing the last side of the box, so that you can view the layout=
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>of the air ducting. I'll put in on the web site and let you know when it is=
 up.
>
>Best,
>Ron O.
>
>--
>_______________________
>
>OVERS PIANOS - SYDNEY
>Grand Piano Manufacturers
>
>Web: http://overspianos.com.au
>mailto:info@overspianos.com.au
>_______________________
>
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Greg Newell
mailto:gnewell@ameritech.net=20

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