----- Original Message ----- From: <ETomlinCF3@AOL.COM> To: <pianotech@ptg.org> Sent: Friday, August 13, 1999 3:08 PM Subject: V-Pro discussion .... The cast iron cools perfectly uniform as to place no air pockets > and no stress areas due to uneven cooling. Well, then. What were those void in the casting that I hit the last time I was drilling into a Yamaha vacuum cast plate? > A highly superior process. I > have heard that sometimes as many as more than 50% of other companies plates > have to be recast due to imperfections. Who is it that is claiming this? I doubt that OS Kelly recasts more than maybe 0.5% of the plates that they make. And most of those would be due to non-casting related problems. > How is the density different? > Richard, if they are both cast iron how can one be more dense? The iron in vacuum cast plates does seem to be less dense. I am not a metalurigist, but I have been told it is because the alloy has to be somewhat different. I do know that the cross-sections in these plates are generally a bit heavier. None of which makes them necessarily worse for piano plates. Not better, either. Just different. Until someone tries to make it into a misleading sales pitch. Del
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