Thanks Ron Overs Good advice all round. I'll sand blast monday & then oh so much fun Dale S. Erwin www.Erwinspiano.com Hello Daleand all, You've had alot of good advice from others. We finishour plates with automotive finishes, either acrylic lacquer withsingle pack primers, for the budget jobs, or 2K two pack withpolyurethane 2 pack high build undercoat, for the seriouswork. When a platehas been refinished previously, without proper preparation, like theplate image that Ron N was unfortunate enough to encounter, I believethe only way to guarantee a good outcome is to sandblast everythingoff. But this will remove all of the original factory filling as well,so you'll need to start from scratch. A good high-build undercoat isvery useful, but it is not a good idea to use it for all your filling.If the undercoat film is too thick it can lead to problems later on.Our approach is to use car body filler on the seriously dimpled andbadly shaped plate areas to get the larger imperfections sorted,sanding them to shape with very coarse paper (80 grit), Thepreparation is quite quick, and very much reduces the thickness ofprimer filler which will be required to achieve a quality and wellprofiled base for applying the colour and clear coats. We use apolyurethane two pack undercoat for our remanufactured and our newpianos, which is easy to sand, high build, and it stands up betterunder the 2K paints (we add the gold powder to 2K clear for applyingthe base colour) when compared to single pack acrylic lacquer allpurpose primers. We use the same method with our new pianos also. Webuy our polyurethane undercoat as a white, which the manufacturertints to a biscuit yellow for us. We find this gives a better base forcovering with the gold powder. With grey primer there is a risk ofgetting a result which looks great when you've first applied the goldpowder coat, but sometimes the grey can show through once the clearcoat is applied, where the colour application has been a littlethinner. The biscuit primer gives a much improved result. Many of theOEM 2K primers are already supplied with a biscuit colour, but theyare expensive. We are getting a similar result at less cost with thepolyurethane. Please don'tuse two packs for finishing unless you have a properly ventilatedarea. When I was in my twenties, had black hair, and used 2 packswithout proper ventilation on pianos, I got grey hair. When I stoppedfilling my lungs with isocyanate, the greyness went away. Its backagain today, but that's another story. Regards, RonO. -- OVERSPIANOS - SYDNEY Grand Piano Manufacturers _______________________ Webhttp://overspianos.com.au mailto:ron at overspianos.com.au _______________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20101120/dd0cef1a/attachment.htm>
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