Wimblees wrote: > Del: > > Are you saying that how the ribs are attached to the soundboard is not > important, but rather that what is important is that they are attached firmly? > > This soundboard is horizontal, with the grain running from left to right. I > haven't looked at how the ribs are attached, but does this have any effect on > how long the piano stays in tune? > > A lot of suggestions were given for my out of tune piano, and I want to thank > everyone for contributing. I am confident it is not an atmospheric problem. If > it is a pin block seperation, or if the screws need to be tightened, I can > make those repairs. However, I am inclined to think that glue failure as Del > mentioned, is probably the cause. If that is indeed the problem, is there > anything that can be done to fix it? Or is it time to recommend a new piano? > > Willem Blees ------------------- Wim, I'm simply saying that the practice of not inletting the ribs into the soundboard liner (or rim, in the case of grand pianos) does not result in the loss of soundboard crown. In terms of crown, it matters not. Besides, it is unlikely that the loss of any reasonable amount of crown could account for the pitch dropping problems you described in your original post. In this case, it is apparent that the soundboard is made of laminated something or other. Who knows, it might even be made of wood. (We have to be careful to not use the term "plywood" here because "select laminated softwoods" has a much more expensive sound to it and we can charge a lot more for the piano that way. You know, just like an "ebonized" finish has a much richer sound than simply saying it is black.) Laminated soundboards, even badly designed ones such as this, are generally quite stable. Much more so than their "solid" counterparts. I can think of only two possible causes for the problem you've encountered here. First, it is possible that the plate has cracked -- nay, broken -- somewhere. A "hairline" crack wouldn't be enough. You're looking for some kind of complete separation somewhere. Second, the general disintegration of the back assembly, as noted earlier. The only way to tell for sure is to get in there and really examine things. Pull the action and bottom board and inspect the plate. Thoroughly. The parts you can't readily see, run your hands over. Make sure you've checked out every part of the plate. Then pull the piano out away from the wall and visually examine the back assembly. Look for loose glue joints. Grab the various braces and shake. Put some weight behind it. (Like me, Wim, you'll not have a problem with this.) Before you're finished, you may have to lay the piano back on a tilter and examine the bottom of the back assembly. This is a weak spot in many small, "modern" pianos. Even companies that lavished good structure along the top of the back assembly often skimped down at the bottom. Especially Wurlitzer. A few skimpy screws seated in the blocking between the back posts must doesn't make it. It's easy to say, at this point, that if you find things generally loose just trash the piano. But... Unless the whole thing disintegrating, you should be able to glue/screw/bolt/dowel things back together in a couple of hours. There's one caveat here: This piano was probably assembled during the days of RF back presses. The glue used would have been formulated to cure at high temperatures -- say 185º F or higher. The heat would have come from radio frequency waves pumped into an enclosed (shielded) chamber. For the most part, these presses work quite well. One worker can assemble, glue and press an entire back assembly in a matter of minutes. If something goes wrong with the process, however, it can affect every glue joint in the entire assembly. Funny thing about that glue. It can dry without curing. It may look cured and it may actually be holding the back assembly together. But the glue may have only a fraction of its design strength. So, check carefully. One word of caution here. If you've noticed these abnormal pitch drops, and if you continue tuning the piano until there is a major structural failure that could/should have been detected early on in the process, you could well be held responsible for not discovering it earlier and informing the owner of the needed repairs in time to prevent the ultimate failure. Were it me, I'd be crawling around under and behind this turkey real soon now. -- ddf
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