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Dave Radlauer wrote: > Hi, I noted your posting on ARCSLIST: > > << We have a client with a number of boxes of grooved discs with fungus. > Any suggestions about techniques or labs that offer the service would be > appreciated. >> > > I presume these are grooved vinyl or shellac discs. But if any are actetate > (i.e. one-off recordable discs) These discs are not acetate. Except for some early 30s European discs that have gelatin coatings (and are water soluble), they are cellulose nitrate lacquer, not cellulose acetate. They are properly called lacquer discs, but if you must use a chemical name, they are nitrate discs, not acetate discs. This is because there IS an acetate based disc. These are the transparent Flexo discs that were used by Brunswick for 16-inch pressings around 1933, and the opaque clay colored, slightly greasy, very flexible discs used by World Broadcasting System in the early to mid 30s. (There is a similar opaque blue disc they pressed for another company that have s slight vinegar smell.) > there is another mechanism at work. You may > already know this but acetate discs over time sublimate acidic (acetic?) > byproducts which may appear as mold (whitish dust adhering to surface) but are > not. > > Two tips if this is the case: > 1) Under no circumstance use any cleaner containing alcohol. This is the second time in a couple of weeks that someone has discussed not using alcohol on lacquers while not mentioning that is is SHELLAC that must not be cleaned with any alcohol containing fluid. Where does this come from? While it might not be the most efficient cleaner, I've never seen any problem of using an LP cleaner (which often has a slight amount of alcohol) on lacquer discs-- while these cleaners can be deadly on shellac 78s. The only thing I can think of is a confusion of ethenol (the type of alcohol used in cleaners) and methanol which was noted in Chris Paton's Georgia State study as a problem. She did not mention if methanol was tried directly or in solution. Ethanol is usually less than 1% in record cleaners. > There are > other chemicals to be avoided as well, perhaps other listmates can specify. > 2) One specified chemical used to remove the surface material generated by > this process is Ammonium Carbonate -- approx a tablespoon of powder in a gallon > of distilled water. This is Kodak Lens Cleaner -- NOT to be confused with Kodak Photoflo. > Applicaton of this can be followed up with a very > gentle, neutral surfactant like photoflo or products available from many fine > vendors for gentle cleaning of disc surfaces. > > Best, > > Dave Radlauer > www.JAZZHOTBigstep.com >