---------------------- multipart/related attachment --============_-1144388587==_ma============ >In a message dated 10/31/2003 10:28:57 AM=20 >Pacific Standard Time, collin.s@skynet.be writes: > >Thanks again, Joe. This helps a lot. I'm=20 >definetly not going to recap the bridge. I'm=20 >afraid I could have to be going for a new board.=20 >(Strange, I have never seen varnish on bridges=20 >here. In Bechstein pianos, even no graffite.) > >St=E9phane Collin. > > Varnish is to soft to be a bridge coating=20 >IMHO even if it went on first & graphite doesn't=20 >do much to protect a bridge topeither. I've been=20 >apllying several coats of shellac to NEW bridge=20 >tops. It seals it nicely and it's hard when=20 >dry. It also allows the beauty of the nicely=20 >quartered maple to come thru. I sand it smooth=20 >with fine paper then polish it with a rag. Now=20 >obviously this is done before the pins & strings=20 >go on. Right? > Dale Dale and St=E9phane, I agree with your approach Dale. Similarly, I=20 believe it is critically important that the=20 bridge is envelope-sealed and that the chosen=20 material should have a minimum of hysteresis=20 loss. We currently use a polyurethane sealer=20 which is quite a brittle material (we cover the=20 sound board & cutoff panel, bridges and the=20 action-bay in one spray session - with the pin=20 block removed). For some time we have chosen not=20 to apply a black slip coating on the bridge cap.=20 I believe a black coating can result in an=20 overheated and damaged bridge cap under stage=20 lighting. Furthermore, as Dale mentioned, a clear=20 coat allows the beauty of the quarter cut bridge=20 cap to show through. Regarding the hysteresis loss of bridge coatings=20 (or indeed of the bridge cap itself), I am not=20 much of a fan of the string being in contact with=20 the bridge cap at all. Therefore, the idea of a=20 bridge agraffe would seem to have (in principle)=20 considerable merit. The image below is a=20 grey-scale jpeg of the latest Stuart piano=20 agraffe. The use of a high hysteresis material (such as=20 silicon rubber) on the body of the agraffe would=20 seem to negate a major benefit of using the=20 device. Of course, if there is such a small=20 clearance between the agraffe body and the=20 strings that it causes string noise, one would=20 have little choice but to use a lossy material as=20 a 'cure' (apart from redesigning the agraffe=20 which would be a better solution). Silicon on=20 noisy agraffes 'kills' the tone nearly as=20 effectively as damping out the front duplex to=20 'cure' string noise. By the way Joe G., when the topic "Clamps" was=20 active last week, you asked what "RHS" referred=20 to. It is a standard Australian term in the steel=20 industry for Rectangular Hollow Section. RHS is=20 supplied in a variety of dimensions and wall=20 thicknesses, and is manufactured by rolling a=20 flat section into the required shape and seam=20 welding it. As supplied, its dimensional accuracy=20 is adequate for most construction applications.=20 In terms of strength per unit cost, RHS is=20 considerable cheaper than I beam or H section. Ron O. -- OVERS PIANOS - SYDNEY Grand Piano Manufacturers _____________________________ Web http://overspianos.com.au mailto:info@overspianos.com.au _____________________________ --============_-1144388587==_ma============ An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/93/cd/7b/c0/attachment.htm --============_-1144388587==_ma============-- ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: strtagr2.jpg Type: image/jpeg Size: 30989 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/90/13/41/2a/strtagr2.jpg ---------------------- multipart/related attachment--
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