Using acetic-based silicones near electronics in a closed environment is a well known issue, as the solvents continue to out-gas over time it attacks sensitive components and wreaks havoc at the pin level on fine-pitch IC's.
Your circumstance, and most where one wishes to employ silicone for mechanical reasons, is fine. In fact the electronics-based (RTV) silicones molecular structure does not lend itself well to say, a live hinge. RTV easily rips/tears, where the elasticity of acetic based monomers (again - long chain molecules) have greater pliability and stretch... Quoting Harley Michaelis <[EMAIL PROTECTED]>: > Just yesterday, before the warning messages came in about the silicone with > acetic acid in the formula, I hinged some flaps in a new wing with Loctite > Permatex, a clear silicone. The tube says it skins over in 15-20 minutes and > cures in an hour, fully cured in 24. No servos or wiring were in. > > Today, it is all nicely set up. Wow, those hinges are strong and flexible! > I had sealed the vertical faces of the core along the hingeline with epoxy > and then painted them with Krylon. There is no lingering aroma of acetic > acid and no sign of any eating of the paint. > > Is there now still some insidious danger lurking I should be aware of? > > Incidentally, I used an extremely simple procedure to apply a bead of the > silicone that may be of interest. > > After applying regular, paper masking tape on the bottom of the wing over > the hingeline, I squeezed some of the silicone into a 12CC syringe that had > a #14 sized business end. The hole in the 4" needle is a bit under 1/16" in > diameter. I would have hated to be the horse or bull that had that stuck in > them. I used this years ago in measuring out fluid for developing film. So > the thick stuff would only have to flow a short distance in the needle, I > shortened it to 1" with the Dremel, beveling the end to about 45 degrees. > With all positioned so the flaps were down about 45 degrees, a neat, even > bead of the silicone was run along the inside. I think that was the easiest > hinging I've ever done. > > To keep the syringe useable, I squeezed out what was left over, shot acetone > through several times and ran a wire through the hole. I finished up with a > wad of paper towel and a Popsicle stick. > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > subscribe and unsubscribe messages must be sent in text only format with MIME > turned off. > Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
