<div>What's with what I heard about Strat's? That he soaked the wood in brine, (no oxygen) then buried it in hot sand to bake out the water?</div> <div> </div> <div>Keith Roberts  </div> <div>On 6/6/07, Scott E. Thile <<a href="mailto:scott.thile@murraystate.edu">scott.thile@murraystate.edu</a>> wrote: <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Hello all, A friend is interested in some research he uncovered indicating the benefits of treating softwoods with heat or chemical means to increase sound transmission characteristics and stability. I think the thrust of the research focuses on using currently "inferior" woods in less expensive instruments, especially in light of shrinking supplies of top quality materials and an expanding demand to supply the Asian instrument makers. Some of this research seems to indicate treating already excellent materials could make them better still. Any of you designer/engineer/scientist types had any experience with this as it relates to pianos or done any research with it? My friend, John, relates the following: -------------- "There is a bunch of literature on this, and the indications are that the treatment would improve several characteristics of the wood.  The best option seems to be heating the wood in the 200 deg C range for a period of 1/2 to 4 hours using a method that prevents oxygen from getting to the wood. (in the presence of oxygen the wood degrades pretty quickly when heated). one method is to heat the wood with steam, this removes the air and protects the wood from oxygen.  another is to do it in a pure nitrogen gas atmosphere or in a vacuum.  and there are other methods involving heating in an oil bath, etc.  the result is that it seems to do what aging naturally does over a period of decades, although the heat treatment only takes a few hours. among other things, the wood is 1) darker, 2) stiffer and more brittle, 3) has a higher modulus of elasticity, i.e. higher sound velocity and therefore better acoustic qualities, 4) better stability in response to changing humidity and less tendency to crack with changing humidity, 5) and best of all the moisture content is about 1/2 of that of untreated wood at any particular humidity level.  the one downside is that the wood is not as strong, i.e. it is stiffer and more brittle and will fracture at a lower bending force.  but this weakening of the wood is tolerable and is a function of the amount of heat treatment applied. seems like this might be great option for a piano soundboard and would lead to greater tuning stability, as long as the board was strong enuf to handle the downbearing force." --------------- Here's a link to a presentation from some research at the University of Dresden: <a href="http://campus.murraystate.edu/staff/scott.thile/07_59.pdf"> http://campus.murraystate.edu/staff/scott.thile/07_59.pdf</a> My initial reaction is that the best pianos I've heard are relatively new, or have relatively new soundboards, but older string instruments often have advantages over new ones. The difference no doubt has to do with the amount of tension, downbearing, and other forces at play. I think new, properly seasoned strong wood (weight to strength ratio) has a big advantage in pianos versus lower tension instruments. And conversely, lighter, older and more brittle wood has an advantage in lower tension instruments. So I would think the benefits of this extreme heat treatment would be more noticeable in lower tension instruments than it is in pianos. I just removed a perfectly good soundboard out of the Steinway 'O' I'm rebuilding this summer. I could not detect anything wrong with it at all. I just wanted to replace it with a new board because it has reacted to 40 years of extreme humidity swings (it's not the original board--the piano is 65 years old). No cracks, good crown and me beating the thing out with a sledge hammer ;)). Even I had to cringe, but I'm convinced this is the best strategy here at MSU where we see 60% swings in humidity. Every rebuild gets a new board now! I LOVE the sound of the D I just finished rebuilding this January with a new Bolduc board--it's simply a fantastic board! No extreme heat treatment--just good wood that has been well constructed into a wonderful soundboard with more or less traditional techniques. Would it sound better if it had been extreme heat treated? Perhaps, but how would it age? Is the life span reduced as the tonality is increased with extreme heat treatment? My guess is it is. Perhaps like putting the thing in a time machine. Yes, it may sound better, but for how long? If the board needed to be "beefed up" in order to compensate for the reduced strength, does that negate the tonal effect? I bet it does.... The most compelling thing mentioned in the research is that the treated wood takes on less moisture. Perhaps reducing the expansion and contraction due to humidity swings, which would help with the situation we have here at MSU (and many other locations), and that would add as much life as the loss of strength would reduce, and if it also contributed to better tonality and more stability, well that really would be interesting. Sorry this is so long, but I thought it was interesting. Any of you bright boys in back rooms have a take on this? Scott Scott E. Thile, RPT Piano/Instrument Technician --------------------------- Dept. of Music, Murray State University 504 Fine Arts Building, Murray, KY 42071 Office Phone: 270-809-4396 <a href="http://campus.murraystate.edu/staff/scott.thile/index.html">http://campus.murraystate.edu/staff/scott.thile/index.html</a> </blockquote></div>