Dave Kruger wrote: > Michael Daly wrote: > > > > [... alcohol effect on polycarbonate lenses] > Michael, most likely the "alcohol" you used was *denatured with* materials > which DO leach or affect the polycarbonate, as pure "grain" alcohol (we call > it Everclear around here -- gotta get it from a liquor store) has no > denaturants in it, only 5 % water. I used 70% isopropyl alcohol, 30% distilled water from a drugstore.(likely to have some small amount of unknown contaminants). In the old days, I used 35% isopropyl alcohol with the rest distilled water and a couple of drops of dishwashing liquid per litre. This was recommended by Celestron for my telescope optics. (Some folks I know use 100% isopropyl for cleaning optics.) This worked well for my glass eyeglass lenses, but proved to be a bad idea when I got my first pair of polycarbonate lenses a few years ago. Interestingly, GE says you can use isopropyl alcohol for cleaning fresh paint spills off of LEXAN (http://www.structuredproducts.ge.com/products/tech_data/cleaning.html). For regular cleaning, they recommend other materials. I haven't found specific info on the web to back up the claims made (that I have repeated) that alcohol damages polycarbonate. Nonetheless, I have two expensive Nikon eyeglass lenses with a definite pattern in them that got worse with time. The damage is consistent with leaching of surface material from the lens. Sigh... Mike. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sun Aug 15 1999 - 12:00:34 PDT
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