Boral
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drying wood
video posted by Fadel.
http://uk.youtube.com/watch?v=5TT4ukNKpCc&feature=related
At 4:34, it looks like he stores or dries his wood hanging from the ceiling. Can someone point the advantages besides hot air tends to rises up ?
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SamirCanada
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that way, it is not traped between other peices of wood.
I would think it accelerates the drying process by maximizing the exposure to air.
I will let the others weigh in.
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jdowning
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Thanks for the link Boral.
It is of great interest and informative to view the workshops of professional oud makers. I noted the 'solid' mold for the bowl and yet another useful
variation of a bending iron.
The soundboard woods hanging from the ceiling will already have been fully seasoned (dried to ambient room conditions) and 'ready to go' - this is
just a way to save workshop space not to dry wood.
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Boral
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thank you for your answer Jdowning.
I have read some articles about air-dry, moisture content, EMC, etc.
Perhaps this is a silly question but, if I understood well, wood, even if very well dry, will tend to reach equilibrium with the surrounding
environment. I wonder how luthiers did in the old days during the winter because where I live the RH is 60-70% inside the room now (Mediterranean
climate: wet winters and dry summers).
They didn’t have dehumidifiers at that time and only with very high temperatures one will bring back the wood MC to the same values of during the
summer.
Hope it is clear, sorry for my bad English.
Antonio
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jdowning
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You are correct Antonio. Fully dried wood - even after a century of drying - will continue to change in moisture content as the environment of a room
changes. In more humid conditions the wood will absorb moisture and swell. In dry conditions the wood will reject moisture and shrink. Instrument wood
that is quarter sawn shrinks/expands less than flat sawn wood so is more stable and less prone to cracking. Wood blanks when stored during the final
stages of drying to workshop environment conditions, should be end coated with wax (to prevent the blanks splitting due to rapid moisture loss from
the end grain), stacked and 'stickered' to allow air flow between the blanks.
Once the wood has been assembled into an instrument it is less free to expand or contract with humidity change so the humidity of the workshop during
the assembly stage is quite important - dependant upon the average ambient conditions in which the completed instrument will be used during its
lifetime. If an instrument is assembled when humidity is high it may shrink and crack when humidity is low. If an instrument is assembled when
humidity is low it may expand and buckle in high humidity conditions or, in less extreme cases, may temporarily lose some resonance but will not
crack. The latter is, therefore, preferable.
The best relative humidity for instrument assembly is between 40% R.H. and 55% R.H.
In North America, winter conditions can be very dry inside a heated building (20% R.H. in extreme cases) due to the low temperatures outside (down to
minus 40 C) that reduce (by freezing) the moisture content of the air whereas in summer the humidity can easily go to 80% R.H. The opposite would seem
to be the case in the climate of Portugal although I imagine that the environmental conditions year round would be less extreme than in North
America.
I do not have climate control in any of my buildings so would assemble instruments (or furniture etc.) during the winter (but not when it is minus 40
C outside!). In your part of the world, I would guess that a luthier who does not have climate control would choose to assemble instruments during the
summer.
Anyway, rightly or wrongly, this is only my opinion - others may have different comments to make.
By the way Antonio, your written English is excellent - nothing at all to be concerned about!
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Boral
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Thank you once again for your answer John.
Perhaps you are correct, they would assemble during summer.
I have a dehumidifier but in these days I cannot go lower than 60%.
I think I have to wait until the weather is hotter and drier.
BTW, what part of the oud do you think would be more sensible to shrinking?
Since the ribs are wet before bending, I think I could start building the bowl now. The soundboard I would leave to springtime.
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jdowning
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My experience is with building lutes but there is little difference between ouds and lutes from a construction point of view. Of the lutes that I
built in the moist, moderate climate of England (without climate control) and brought with me to the more extreme climate of Canada, I have never had
any problems with the bowls splitting but I did have the soundboard of one lute split due to dry conditions and which had to be replaced. I also had
the flat back of a vihuela split for the same reason so that also had to be replaced. The lute sounded much better after the repairs because the
soundboard had 'locked in' stresses (due to being braced originally in too humid an atmosphere) and which adversely affected the resonance of the
instrument.
So, flat soundboards or guitar/vihuela backs are the most critical sub assemblies once the braces etc have been glued in place (but less so before
that time) and the bowl is the least sensitive. Final assembly of the instrument, however, is best done under optimum conditions of relative humidity
- say around 50%.
A relative humidity of 60% is not too bad but what is the average relative humidity during the hot, dry summer months? However, if you have climate
control in your house where the instruments will be stored you should be able to maintain optimum conditions and avoid any potential problems.
Just my opinion, however.
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theodoropoulos
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i would like to ask something....
here in Greece i have heard of some old men that they were boiling pieces of wood in salted water in order to lose all they juices ....
have you heard something like this????
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jdowning
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Yes. The old Cremonese violin makers were supposed to have boiled their woods in a salt solution before drying the wood - a process that was supposed
to accelerate the aging process by degrading the hemicellulose content of the wood. A centuries old theory going back to at least the 16th C. - but
does it work?
Salting wood is also a standard modern technique where various salts are introduced into the cells structure of wood, under vacuum conditions or by
boiling. The intent usually being to preserve them against rotting or to fireproof the wood. Common salt (sodium chloride), however, attracts moisture
so if present in the wood cells will increase moisture retention for a given level of atmospheric humidity. This may be seen as an advantage in
tending to stabilise the wood against cracking if subject to rapid humidity changes.
Recent analysis of the wood of some famous early Italian violins (Stradivari and Guarneri) has indicated the presence of various kinds of salts within
the cell structure. The presence of the salt is being attributed by some - rightly or wrongly - to the acoustic success of those instruments. How the
salts got into the wood is subject to speculation - by soaking ('ponding' the wood in brackish water for several years or by soaking them in salt
solutions to preserve against decay or insect attack etc. etc.
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theodoropoulos
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we open now one of my research....cremonese violins..the analysis in stradivaris violin showed that there are kinds of minerals between the wood and
the lac.minerals such as Si (piritium) and others....alll those chemical ,in my opinion,worked as a filter in high frequencies which where odd and bad
for the ears....i don't know if they knew what they where doing or this was done by accident...
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jdowning
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I do not make violins but understand that ultraviolet photography has revealed that most of the Strad. and Guarneri violins have lost much of their
original varnish and have been recoated in the past 150 years with modern varnish. Apparently many violin makers today consider that their violins
sound better unvarnished - so while varnish may be necessary to protect the outer surfaces of a violin the varnish is unlikely to improve the sound.
So less varnish is better.
However, the topic of varnish as it may or may not influence the acoustic properties of a violin is off the topic of drying (seasoning) wood. The
salts found in violins, mentioned in my previous post, refers to salts found within the wood itself. One researcher, Joseph Nagyvary, speculates that
the early Italian violin makers used some form of treatment that happened to substantially alter the composition or structure of the wood and improved
the acoustic properties (but was probably originally intended to accelerate the seasoning process). He was able to analyse fragments of wood taken
from Stradivari instruments to find that the wood contained very high concentrations of salts. Unable to find a process that would replicate these
levels of salt concentrations in wood, he started using sunken timbers that had been immersed for centuries in a freshwater lake and were found to
have absorbed minerals that closely matched the content of those in the Stradivari samples.
Nagyvary's discovery about ponded timbers is not new as the ancient Celtic tribes of Ireland made their harps from bogwood - ancient timbers dug from
peat bogs whose composition had been dramatically altered by the minerals in the bog - the timbers having been immersed for centuries if not thousands
of years, becoming partially fossilised in the process. Bog wood requires slow and careful seasoning after being removed from a peat bog otherwise it
will split badly. I imagine that Nagyvary's timbers might also need to be carefully dried after being recovered from the lake bed.
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theodoropoulos
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i have heard many theories but in one scientific article there was an investigation about stradivari's varnish.It refered that he used a powder made
of stones such as quartz,coralls,plaster,emerald and many substances full of piritium...
this powder was so thin that is very invisible even today.it was the secret that gave this special sound in violins,as i mentioned it worked as a
filter in ultra high and odd frequencies generated by the bow.
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theodoropoulos
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let me ask you something.i just got a fine cocobolo wood which was cut 1 year ago.How long does it take to dry ?
dimensions 70cmx18cmx6cm
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Boral
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I have heard that one can count like: one inch- one year to dry.
Here in Portugal people say: 1 cm-one year.
Perhaps other more informed members can give you a more precise answer
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jdowning
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It depends more upon the species of wood rather than thickness - a wood with a relatively low specific gravity will dry much faster (without defects)
than a dense tropical hardwood. Either way make sure that the wood is coated with wax at the ends to minimise risk of checking and take your time -
very gradually introducing the timber into increasingly dryer environments.
I have successfully 'accelerated' the processing of end coated blocks of 'green' African Ebony by first cutting the wood into fingerboard blanks,
veneers etc. and then allowing the blanks to slowly dry in a well ventilated unheated outside building for a few years until required for use. If you
have enough material accumulated in stock there should be no need to rush. Otherwise, purchase ready cut and dried stock from luthier supply houses -
material that will only require a short period of acclimatisation to workshop conditions.
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theodoropoulos
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mr jdowning if i cut the ribs now ,how long must i wait to dry???is it correct to do it ,or they will twist by drying??
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jdowning
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Impossible to say as each chunk of wood is different. It would depend upon how the wood has been stored and under what environmental conditions, how
the grain runs and how you intend to cut the wood. If you have highly figured wood, significant longitudinal grain run out (spiral growth) and slab
cut the ribs you will be more likely to experience twisting and distortion on drying fully - but you might also find that problem if you cut a piece
of wood that has been kiln dried or air dried too quickly or contains 'tension wood' - due to build up of internal stresses that are released when the
wood is cut.
Nothing is guaranteed.
Even when cut into thin rib blanks it would still be best to leave the blanks to air dry further for several more years if you can afford the time -
leaving sufficient excess thickness to allow for shrinkage and so that any inevitable slight cupping or distortion occurring during drying can be
planed out.
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Oud.Proff
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Soundboard-drying
About drying the wood, one of the late Mohammad Fadel sons once told us that Osta Fadel used to do something really interesting to the soundboard
after he fixes the braces and does his "magic touches with the soundboard": he'd go to a nearby bakery (old type; similar to what's known as the
"Taboon") after the fire has been put off, and leaves the soundboard nearby it overnight, allowing it to dry real well and easy. The unparalleled
sound quality of his ouds, and durability/prolonged structural integrity of the soundboard were unique aspencts about Osta Fadel ouds indeed.
Sad thing though, I was recently told that the whole workshop itself of Osta Fadel is now a bakery ! 
That's a picture of "old" Osta Fadel playing one of his ouds in the workshop.
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Tom Moran
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Thanks for posting such a wonderful photo!
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theodoropoulos
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very interesting opinion but i believe that the wood's moisture must not be beneath 13% becasuse it will crack in the future....
we use here in Greece in Crete in soundboards cedar of Libanon ,which is found only in very old houses.They are over 200 years old ,so the are well
dried all these years
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