Thanks, Walt. This is exactly what I was hoping to learn. Best, Andy Baron
On Feb 9, 2007, at 10:48 AM, Walt wrote: > There has to be at least one piano tuning expert out there who > knows this > better than I do....But here it is in a nutshell.... > > It's not really the glycerin that is the problem, but water. Glycerin > certainly facilitates the problem, however. The glycerin when mixed > with > additional alcohol is able to penetrate into cracks, crevices and > wood pores > quite deeply. Glycerin on its own would not penetrate very well. > The alcohol > quickly evaporates, but leaves the glycerin in the pores. > > HERE IS THE PROBLEM: > Glycerin loves moisture and it draws water out of the air to bind > with it. > As the water is adsorbed, it fills spaces in the cellulose (wood > fiber) and > increases the hydrostatic (essentially of the water) pressure > within the > wood. This expansion pushes the wood fibers outwardly and causes > sections of > joined wood, for example, to more tightly fit together. That all > sounds well > and good IF the expansion that occurs in the wood was a permanent > change, > but it is not and herein is the difficulty. The ability of wood > (cellulose) > to wick liquids is greater than the glycerin's ability to stay in > place. So > the water is eventually forced to leave the wood. The expansion > also crushes > the cellulose structure of the wood which is not reversible. > Eventually, the > wood may dry out again and you will have to do your magic glycerin > treatment > again and again and again. But in time, the introduction of the > moisture > coupled with the repeated expansion and contraction (i.e. getting > wet and > then drying) will rot the wood, and not only that, it will rust any > metal, > like nails, tacks, and brads that it comes in contact with. Any > rust that is > formed will shed from metal when the wood dries out and cling to > the wood > fibers. The more this expansion and contraction takes place, the > more rust > is formed, the smaller the nails get, and the looser the joints > become. At a > point, the nails lose their ability to fasten. Everyone has seen a > rusty > nail or screw in hole that just falls out of a hole - same problem. > > A GOOD piano guy would know the danger of this around things like > tuning > pegs. > > Needless to say, I am an advocate of doing things the right way and > I don't > advocate the use of snake oil (I mean and glycerin) for > 'restoration'. If my > car leaks oil it doesn't need a chemical to expand worn gaskets, it > probably > needs new gaskets. The chemicals that expand gaskets in cars like > to stop > oil leaks are often used by people who just want to push their > problem off > to the next owner. A piano tuner who uses glycerin is ALWAYS more > interested > in lining his pockets with your money than he is with the long term > performance of your piano. > > Getting into an Orthophonic to seal the horn (or removing them if > necessary) > isn't easy, but we have marvelous things like silicone adhesives > which, once > they are applied, are apt to outlive the wood. > > Walt > > > > > -----Original Message----- > From: [email protected] [mailto:phono-l- > [email protected]] On > Behalf Of Andrew Baron > Sent: Friday, February 09, 2007 11:46 AM > To: Antique Phonograph List > Subject: Re: [Phono-L] orthophonic/credenza question > > When you have a few moments, could you enlighten me with some > additional information on what glycerine specifically does to the > wood, short and long term? > > Thanks in advance, > Andy Baron > > From: [email protected] > Subject: Re: [Phono-L] orthophonic/credenza question > Date: February 9, 2007 6:23:33 AM MST > To: [email protected] > Reply-To: [email protected] > >> But note that he advocates the use of glycerine to "rejuvenate" the >> wooden >> horn - and that glycerine is also used on pianos in the same way, >> but by only >> the worst, shoddiest tuners. It's a cheap, quick way to ruin wood. > > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.411 / Virus Database: 268.17.32/677 - Release Date: > 2/8/2007 > > > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org
