Dear Wim and all, Probably the easiest way to understand the question is to recall that there are many kinds of plastics, and they don't all behave the same way. Here's more detail: Keytops are basically acrylic, which is a plastic formulation containing carbon, hydrogen, and oxygen. The oxygen molecule is very attractive to electrons (negative charges), and the resulting plastic has its electrical charges unevenly distributed, more electrons near the oxygen molecules. High-density polyethylene (recycling label #2) is used to make chemical storage bottles. HDPE is made up only of carbon and hydrogen and has its electrical charges evenly distributed over its whole area. Acetone, because it is made up of carbon, hydrogen, and oxygen, has uneven distribution of its electrical charges. It readily dissolves (mixes with) other unevenly charged compounds, such as acrylics (keytops) but is repelled by and does not mix with evenly charged compounds, such as HDPE (container bottles). That's the story. Best wishes, Dorrie Bell Ph.D., Physical-Organic Chemistry, Brandeis University Associate Member, PTG Original Message: ----------------- From: Wimblees@aol.com Date: Fri, 25 Apr 2003 12:08:10 EDT To: Pianotech@PTG.org, caut@ptg.org Subject: melting plastic SOT Melting Plastic, SOT, (Slightly Off Topic.) For hammer juice, I use acetone and keytops. I keep this solution in a plastic bottle. I'm no chemist, so how come the acetone dissolves the plastic keytops, but doesn't dissolve the plastic bottle in which it is kept? Wim PS. Before I get blasted for using this stuff in the first place. please be assured I use it very sparingly only on Steinway hammers when I voice. These Steinway hammers are first given a liberal dose of lacquer and lacquer thinner, as per factory specification. I don't use any kind of juice on other hammers. (I keep the lacquer mixture in a plastic bottle too, (a mustard bottle), and it doesn't dissolve either.) -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .
This PTG archive page provided courtesy of Moy Piano Service, LLC