<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2600.0" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><0:)</DIV> <DIV>Joe Goss <A href="mailto:imatunr@srvinet.com">imatunr@srvinet.com</A> <A href="http://www.mothergoosetools.com">www.mothergoosetools.com</A></DI= V> <BLOCKQUOTE dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black">From: <A title=skolnik@attglobal.net = href="mailto:skolnik@attglobal.net">David Skolnik</A> </DIV> <DIV style="FONT: 10pt arial">To: <A = title=pianotech@ptg.org href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV> <DIV style="FONT: 10pt arial">Sent: Saturday, March 30, 2002 = 10:07 AM</DIV> <DIV style="FONT: 10pt arial">Subject: Re: Case separation or = delamination question</DIV> <DIV> </DIV>Hi Terry - At 08:52 AM 03/30/2002 -0500, you = wrote: <BLOCKQUOTE class=cite cite="" type="cite">This is a long post = about rim delamination.</BLOCKQUOTE> Actually, it only seems long, most = likely because I used the shorter line width that people seem to prefer, and = because I use too many commas. I also try to save space by not using smiley = faces, but I think them a lot.  Also my apology took up a few lines. <BLOCKQUOTE class=cite cite="" type="cite"> If I understand = you correctly, you are concerned that the rim delamination is causing = the tonal deficiencies.</BLOCKQUOTE> That WAS the = point of my original question. By the time of the post to which you responded I = was trying to confirm and clarify my understanding of what Del had said, which, = overall, left me feeling that this might not be as big an issue as I had first thought.  I offered as little information as I thought was = necessary to focus on that question, but, judging from a few of your subsequent = comments, that may not have been adequate. <BLOCKQUOTE class=cite cite="" type="cite">I'm no rim = professional, but I suspect all you need to do with this rim is to flip the piano over = and fill the little rascal gap with West System epoxy. </BLOCKQUOTE> I haven't the means to simply flip this 8' sucker = over. (Good thing it's only 85 notes)  Even if it hadn't just been = rebuilt, I would want to know that it was likely necessary before I undertook the = expense. <BLOCKQUOTE class=cite cite="" type="cite">Ok, so now you have = the rim taken care of. Time to consider the cause of the tonal deficiencies. You = have a flat board with a dead treble. You mention the piano was rebuilt. = New soundboard? Yes Who made the = soundboard? Not relevant, other than to say it was done by = experienced rebuilder        Original = 119 year old Steinway soundboard? Yikes! If that is the case, I would = consider focusing on the need for a new soundboard. (This kinda sounds like = the situation to me!)  No</BLOCKQUOTE> The question for me was whether there was any reason = to suspect that the delamination would likely have contributed to the apparent = lack of crown in a newly installed board. <BLOCKQUOTE class=cite cite="" type="cite">Fully evaluate crown = and downbearing over the entire soundboard to better understand your soundboard's condition.</BLOCKQUOTE>Terry, I'm = just curious.  How would you go about measuring the downbearing? (:-!) See, I can't seem to get a good = smiley (;-( David Skolnik <BLOCKQUOTE class=cite cite="" type="cite"> ----- Original = Message ----- From: "David Skolnik" <skolnik@attglobal.net> To: <pianotech@ptg.org> Sent: Saturday, March 30, 2002 1:09 AM Subject: Re: Case separation or delamination = question > Thanks Del & Zen for your replies. First, a bit of an apology. I = cross > posted to the CAUT list because I suspected that there are = some people who > are on there exclusively, remembering afterwards = that I, myself have > sometimes found it confusing when the same = thread subject is being carried > on simultaneously on both lists, = sometimes with cross posting, and at other > times on only one or the other.  I considered forwarding the CAUT responses > to = this list & visa versa, but suspect that will just make things worse, = > so, for now, if you're interested, there are some other = responses on the > other list as well. > > The piano in = question is an old Steinway C (?) 85 note from about > 1883.  = (There was either a recent posting or it was on someone's web site > = that I saw an excellent listing of old models and dates.  I can't find it = > at the moment).  The delamination between inner and outer rims = goes > completely around the perimeter.  The visible gapping = is generally from 1 > to 2mm.  I only had a flat steel = handled upright mute (.5mm or .020") to > use as a feeler gauge & = it tended to insert between 1 to 2 inches throughout. > > = The piano was recently rebuilt (within the last year and a half).  = There > have been significant tonal deficiencies, especially in the = 5th and 6th > 8ve.  From the 7th rib up there is no apparent crown.  I didn't notice the > delamination when the = piano first came back, but, in spite of a few months > out of the year of = rather low humidity (20%), I doubt that such a degree of > = separation would have happened in such a short time. > > The main = question for me is, what design parameters are impacted, and to > what = degree, when there exists a significant amount of inner rim -outer rim = > separation of a unified rim design. > > At 09:35 AM = 03/29/2002 -0800, Del wrote: (Edited) > > >Rim delaminations = are usually not a matter of great concern--at least not > >structurally--unless the delamination is evident for some considerable > >distance or the affected area is = expanding. > > >There is far less stress > >on piano rims than = is commonly thought. > > What are the sources of stress in = a single rim construction? The initial > bending creates the = classic tension/compression stress.  Spreading the arms > to fit = the pinblock relaxes some of that stress, but stresses the cured = > glue joints. Some stress is transferred from the strung plate. and = perhaps > some outward stress from the compression of the = soundboard.  Some of the > stress is internal, some imposed.  Would = the acoustical properties of the > rim change over time, as the = internal stress dissipates? > > >With the now much more = common style of rim construction in which the piano > >is basically = built on a separate inner rim with the outer rim being added > >down = the line somewhere, the most common problem involves getting the = joint > >between two rims just right. > > >Structurally = and acoustically there is no advantage to either style of rim > >construction as long as each process is done reasonably well. A = glue joint > >is a glue joint and it matters not whether the = entire rim is formed in one > >pressing or in two pressings that are = later glued together. Having worked > >with both I now have a = preference for the so-called two-piece rim > >construction. The = resulting rim is at least as strong and the piano is much > >easier to = build accurately. > > So, what purpose does the outer rim = serve, in a Steinway?  Would you > suspect any discernable = difference between a Steinway built in the > traditional manner and one constructed with a 2 part rim?  For that matter, > when = did Steinway begin unified rim construction? > > >In = most cases I wouldn't be overly concerned about the small areas of = veneer > >delaminating often found in otherwise serviceable pianos. Keep = an eye on the > >area involved but, unless the delaminating is = spreading, it's probably not > >going to cause any real = problems. > > >As part of the rebuilding/remanufacturing process the = rim should be examined > >for potential structural problems. = If, during this examination, any rim > >delaminating is found the gaps = are filled with epoxy. > > In an older instrument such as = the one I have described, I would assume > that most, if not all of the = original internal tension has relaxed.  Unless > the = outer rim contributes to rigidity of the soundboard mounting, affecting = > crown and energy reflection,  the only reasons I can see addressing = rim > separation would be either cosmetic, to prevent potential = transient > vibrations, or to keep it from getting worse.  Have I misunderstood or > misstated your position, or does this = correctly reflect your thoughts? > > Thanks - > > = David Skolnik > > > = </BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>