This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment John, I have found buffing to be more of an art than a science. When your = buffing ivory and bone you are doing two things, one is smoothing the = surface and removing fine scratches, the other is sealing the pores. = When your buffing plastic you are smoothing and removing fine scratches = and not necessarily sealing it because plastic is not porous. I have = found that a sewn canton flannel buff followed by an loose canton = flannel buff works well for me. Take into consideration that when you = are buffing you are simply putting the icing on the cake. What do I = mean? Buffing is to shine and seal (in the case of ivory and bone.) The = surface preparation should already be done. Buffing removes fine = scratches well, and will leave a perfectly flat surface. If one relies = on buffing to remove deep pits and scratches, this is where problems = arise. The surface will not be perfectly flat, and heat will be = generated. Heat will crack and burn ivory and bone, heat will melt and = deform plastic. The trick is surface preparation, keep the key moving, = and apply the proper pressure. Compound or rouge plays a role also. = Compound can contain abrasives, you want to be sure that you are using a = buffing compound and not a cutting compound. A cutting compound will = leave as many scratches and lines in the top as you are trying to = remove. I look at buffing keys as I look at refinishing a piano case. = Your surface preparation and repairs must be done first, spraying = lacquer on a piano sanded and left in 80 grit will not be as smooth and = look as good as a case sanded to 600 grit, grain-filled and sprayed. ----- Original Message -----=20 From: John Ross=20 To: Pianotech=20 Sent: Sunday, March 06, 2005 12:06 PM Subject: Re: Moulded Keytops, problems buffing Hi, Joe had mentioned problems buffing. I also have problems in this area. I had thought on a softer buffing wheel, but have been unable to find = a source. The selections available at my suppliers, are limited.=20 Any ideas? I had thought on slowing the wheel down. Would that help? John M. Ross jrpiano@win.eastlink.ca=20 From: MICHAEL MORVAN=20 To: Pianotech=20 Sent: Sunday, March 06, 2005 11:50 AM Subject: Re: Moulded Keytops Joe, I agree with you 100%, thank you, it is wonderful that you know = these things and are willing to share them. Molded keytops are all the = same dimension within one set. Keysticks unfortunately are not (except = for several sets of Yamaha keys I've covered that were within 0.004 of = each other). I've found that most sets of keys differ in length, width = and height. I have one set of keys I'm recovering now where the = keysticks vary in width up to 0.065. This makes recovering them tricky. = If you have a keystick wider than the top you will have to trim the = stick, if the top is wider you will have to trim the top. Molded tops = being the same width have the contours and radiuses "molded" into them, = so if you trim this you will, as you said then have to reshape them, the = radiuses and contour to match and yes, the dreaded buffing. I prefer to = apply what I call custom tops. This is similar to factory procedures in = which you apply a separate top and front. If done this way one can trim = the excess and shape the keys regardless of the inconsistencies in width = and yield good visual results. I've found that buffing plastic and ivory = both have there areas of concern, but I use different wheels and = techniques for both with good results. On the topic of keytop materials, = I'm pretty sure I have all of the material available within the states = and offer them. I have also acquired material from Aug. Laukhuff and = Otto Heuss from Germany as well as P&S organ supply from England. These = materials are of very high quality and texture but expense prevents = their wide use. I've noticed that piano manufacturers are trending = towards thicker and thicker tops, this means replacement tops will need = to be thicker. I actually have a stash of keytop material that is 0.105 = thick, but very rarely use them. I am not adverse to machining down the = keystick to accommodate a new top because I am doing it on milling = machines with tolerances to within a few thousandths of an inch, and it = must be done. If one measures a keystick at 0.970 and is putting on a = top that is 0.075 than you machine the key to 0.895 and you have = retained the original dimension. The original dimension must be = maintained or there will be a regulation nightmare. In some cases I find = that a keystick has been machined with little regard for tolerances, and = then a corrective measure must be applied. Three choices exist, have a = new keyboard made, use a thicker or thinner top (depending on which = direction the error is made), or build up the keys. Two of these choices = are very expensive. Keytop replacement is tricky and is a decision that = should be well thought out. The keyboard is a major focal point of the = piano, it is the interaction point with the piano and is the foundation = of all regulation. It is a challenge to balance appearance, playability = and economy. Joe, what do you mean by "stink in my shop?" are you = referring to a particular glue or the smell of machining off old plastic = and ivory? Mike ----- Original Message -----=20 From: Joe Garrett=20 To: pianotech=20 Sent: Sunday, March 06, 2005 1:03 AM Subject: Re: Moulded Keytops Michael Morvan said: "The quality of the keytop, quality of the = =3D piano, quality of the rebuild, preference of the customer, = knowledge and =3D preference of the technician and budget. Crappy "molded" keytops = are =3D nice if applied properly, and three thousand dollars worth of new = ivory =3D is "crappy" if not applied properly. Molded keytops have the = advantage =3D of being inexpensive, uniform in shape and appearance, and = relatively =3D easy to apply with minimal skill, tooling and yields fair results. = A =3D disadvantage is that many people feel that they are a cheap top = and as a =3D result do not use them." Michael, What you've said, I agree with. However, it's what you didn't say = about moulded keytops that concerns me. 1. Moulded keytops assumes that all key sets are the same = dimension, which they are not. Therefore, trimming is necessary. Here = lies the rub, as trimming of moulded keytop material is far more = difficult than other materials. Especially in making the key set look = consistant and have a smooth feel under the players hands. Secondly, if = you've ever had to (try) to buff out scratches of moulded key top = material, (and I'm sure you have, if you do keytops for a living.), it's = next to impossible, as the material is too soft and will "burn/gaul" = when even light pressure on a buffing wheel is applied. I'm not saying = it can't be done, but it's a royal pain in the patoot to do!<G> Lastly, = my aversion to moulded keytops is that it is too thick, especially for = many older pianos with tight tolerances of the piano furniture. This = requires milling the keystick down. I am totally averse to this practice = for many reasons. Some of the "moulded keytop material" from Europe is = better as some of it is what we call "Plexiglass". This material can be = sanded and buffed. It's still too thick for my eye.<G> I too do keytops, = but as only part of my overall service to my clients. I used to have = someone else do it, as I really don't like the stink in my shop. Out of = frustration with others I've taken to doing it....stink or not.<G> Regards, Joe Garrett, R.P.T. Captain, Tool Police Squares R I ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/8b/40/63/44/attachment.htm ---------------------- multipart/alternative attachment--
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