>A mix of something sort of like model airplane dope (but not quite) is >poured over a wide pan of water, and it spreads out like an oil slick. >The mix floats on the water until it sets, at which point a frame >(submerged in the water) is pulled up under it Hey this brings back fond memories of my transmission electron microscope days when we did a procedure similar to this (we first poured a bit of the solution onto a glass slide, let it dry, then floated the film off the slide onto the surface of water) to provide an ultra-thin support for samples to sit on. The solution is called collodion. The solvent was amyl acetate (pentacetate--smells like banana extract), and the material that was dissolved in it was nitrocellulose--see http://www.collodion.org/q&a.html. It was very tough stuff; I remember because I occasionally had to make up a new solution using the solvent and strips of nitrocellulose, and the strips were extremely stiff. We always did it in a fume hood. Although we wanted our films to be extremely thin, I'd guess you could control the thickness of the film by varying the concentration of the collodion solution. David Berkeley CA USA RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
