Facts and nots : was Recommend Rebuilder?

[Marcel Carey]

Thanks Terry,

I know that kiln drying can be controlled better than air drying for cut
lumber, but could a log eventually dry as a log (before it's made into
planks)?
Could that make a difference?

Marcel

> -----Message d'origine-----
> De : pianotech-bounces at ptg.org 
> [mailto:pianotech-bounces at ptg.org] De la part de Farrell
> Envoyé : 22 mars 2007 19:51
> À : Pianotech List
> Objet : Re: Facts and nots : was Recommend Rebuilder?
> 
> 
> ----- Original Message ----- 
> >I have questions. Is it possible that the pianos made before 
> the 50s  
> >were made using wood that was seasoned more?
> 
> If seasoning is defined as air-drying, then yes.
> 
> > Is it possible that the
> > fast drying of the spruce that is used today has changed the way it 
> > will swell and shrink with time?
> 
> Well, yes it is possible. And it is possible that improper 
> kiln drying will 
> be detrimental to spruce over time. However, one really needs 
> to understand 
> the basic process of wood drying. Air-drying of wood can be 
> very good - but 
> only under controlled circumstances. If the wood dries out 
> too quickly (easy 
> to do with air-drying - uncontrolled sun, uncontrolled humidity, 
> uncontrolled wind speed, uncontrolled temperature, etc.) it 
> is easy to 
> permanently damage the spruce.
> 
> PROPER kiln drying is by far the best, most controlled, way 
> to dry green 
> spruce. One can damage wood just as easily with kiln drying 
> as with air 
> drying. Maybe I should correct that. One has control over 
> kiln parameters, 
> so it is easier to monitor/control environmental wood drying 
> parameters. 
> With air-drying, one has little if any control.
> 
> And believe me, I know. I have had shipments of green wood 
> arrive at my shop 
> and have had a dry weather spell - the spruce starts cracking 
> within a day - 
> if you don't have the means to control RH and move air you 
> get in trouble 
> real fast.
> 
> Bottom line: Old methods of drying wood - fine many times, 
> sometimes maybe 
> not so good. New methods of drying wood (modern kiln): If 
> used properly, is 
> much better and more reliable than air drying. But again, 
> only if done 
> properly.
> 
> Terry Farrell