At 07:57 PM 22/08/99 +0000, you wrote: > >> >>Thanks also for your response on the V-Pro discussion, I'm not sure I'm >>convinced.......I have been led to believe (and stand to be corrected that >>slower cooling means that the skin of the cast iron is softer compared to >>the sand cast stuff......comments? >> > >Hi Mark. > Thank's for the info on Renner and Maple, now I'm a little wiser. > >On V Pro vs sand cast. > >Point one V Pro is an iron alloy , and is not true grey cast iron, the ad datives are used so that the plate does not fall apart due to the rapid cooling. >Point two the sand is wet prior to the pour and the electrical heating tapes are turned on full bore at the start of the cast, the wet sand I think has a case hardening effect on the skin of the cast, but I will have to drag out my dusty old metallurgy books to confirm this. >Since this discussion has been going for a bit I think that may be a good idea. >The variables are, Hardness, ductility, compression strength. machining qualities ect. I am sceptical about the acoustic properties, one vs the other but the difference in mass has to enter into the equation. The V Pro plates definitely seem thicker, is it to get the same rigidity????? I don't know. so you have me thinking. > >Regards Roger > >P.S. What's the dates of your convention? Roger Jolly Baldwin Yamaha Piano Centre Saskatoon and Regina Saskatchewan, Canada. 306-665-0213 Fax 652-0505
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