> i double checked kokatat's instructions, which say denatured alcohol, or > acetone, to clean. i'm curious - is acetone's negative effect on urethane > only while in direct contact, or does it set up some residual negative, > ongoing reaction? > Maybe what we have here is a case of theory and practice clashing head-on. Searching the internet for urethane and acetone will yield hits that indicate the incompatibility of ketones with urethanes, which demostrates the theory of acetone/urethane incompatibility. There was one link that explained how a urethane coating manufacturer uses MEK (Methyl Ethyl Ketone - acetone's next larger cousin) as a challenge agent for testing various urethane formulations. Another link for a manufacturer of O-rings presented a chart indicating acetone's incompatibility with many commonly used O-ring materials, including urethane. In practice, a quick swipe with an acetone-wetted cloth will should do not harm to a urethane-coated fabric, but extended contact is probably not a good idea. Another aspect of theory and practice is that urethane chemists can alter the urethane formulation in about a million different ways, allowing for the production of a urethane product that might be soft and flexible, or hard and tough enough to be cast or machined into a gear in some piece of machinery. Kokatat no doubt uses a good urethane formulation for their dry suits/tops, and feels that occasional use of acetone will do no harm. Do other paddlegear manufacturers use as good a urethane coating? Why take a chance? If there are alternate solvents that will do the job, why risk the use of a solvent that is known to adversely affect the class of material who's integrity is so important in protecting us from the cold and wet. Besides, acetone is a more volatile and nastier (healthwise, IIRC) solvent to use. My apologies for making it sound like acetone should never touch urethane. As with everything else, the gray areas are much larger than the black or white ones. Regards, Erik *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Fri Apr 06 2001 - 06:25:38 PDT
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