Being said all the good thing about silicone, I believe few years ago, there is a dissociation of silicone (reverse polymerization) under some specific solvent/RH related condition (oil based, If I remember correctly). As long as someone fully understand the application, you will select a good coating for environmental protection. Otherwise, there is no "one coating fits all" stuff... May be some grad student should start a PhD thesis on that... jk >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis >Sent: Monday, September 08, 2003 10:31 AM >To: [log in to unmask] >Subject: Re: [TN] Silicone conformal coating > > >Of course silicone will repel liquid water, but we are talking >here of water in a gaseous phase and my experience is that it >passes small molecules, such as water, like a sieve. In the >former case, it is a question of the high surface tension of >water, but single molecules, ata a time, have no surface, >therefore no surface tension. > >Brian > >Misner, Bruce wrote: >> Brian, >> >> This diaphram experiment does not take into account the surface >> wettability of Silicone which is supposed to be one of its major >> protective features (according to Dow) which precludes surface >> droplets from forming. Comments? >> >> Thanks, >> Bruce Misner >> >> -----Original Message----- >> From: Steve Gregory [mailto:[log in to unmask]] >> Sent: Monday, September 08, 2003 8:54 AM >> To: [log in to unmask] >> Subject: Re: [TN] Silicone conformal coating >> >> In a message dated 09/05/2003 2:03:30 AM Central Daylight Time, >> [log in to unmask] writes: >> >> >>> I thought I had reported the details of this in >>> my book, but could not find them today. Must have been >somewhere >>> else. >> >> >> >> Hi Brian! >> >> It is in your book, on page 329, at the bottom of the >section where >> you talk about Silicone Elastomers. >> >> In your book you state that you made a diaphram of >silicone that was >> 5mm thick, and 100mm in diameter. On one side the air >was held at 40 >> degrees C., and 95% RH, the other side at 5% RH. There was 1g of >> water vapor per day allowed to pass through the silicone >diaphram. >> You stated that is 40 times worse than epoxies, and 20 >times worse >> than polyurethanes. >> >> Do you have any idea about arcylics? >> >> Regards, >> >> -Steve Gregory- >> --------------------------------------------------- >> Technet Mail List provided as a free service by IPC >using LISTSERV 1.8e >> To unsubscribe, send a message to [log in to unmask] with following >> text in the BODY (NOT the subject field): SIGNOFF Technet >> To temporarily halt or (re-start) delivery of Technet >send e-mail to >> [log in to unmask]: SET Technet NOMAIL or (MAIL) >> To receive ONE mailing per day of all the posts: send e-mail to >> [log in to unmask]: SET Technet Digest >> Search the archives of previous posts at: >> http://listserv.ipc.org/archives >> Please visit IPC web site >> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >> information, or contact Keach Sasamori at [log in to unmask] or >> 847-509-9700 ext.5315 >> ----------------------------------------------------- >> >> --------------------------------------------------- >> Technet Mail List provided as a free service by IPC using LISTSERV >> 1.8e To unsubscribe, send a message to [log in to unmask] with >following >> text in the BODY (NOT the subject field): SIGNOFF Technet To >> temporarily halt or (re-start) delivery of Technet send e-mail to >> [log in to unmask]: SET Technet NOMAIL or (MAIL) >> To receive ONE mailing per day of all the posts: send e-mail to >> [log in to unmask]: SET Technet Digest >> Search the archives of previous posts at: >> http://listserv.ipc.org/archives Please visit IPC web site >> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >> information, or contact Keach Sasamori at [log in to unmask] or >> 847-509-9700 ext.5315 >> ----------------------------------------------------- > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV >1.8e To unsubscribe, send a message to [log in to unmask] with >following text in the BODY (NOT the subject field): SIGNOFF >Technet To temporarily halt or (re-start) delivery of Technet >send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail >to [log in to unmask]: SET Technet Digest Search the archives of >previous posts at: http://listserv.ipc.org/archives Please >visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for >additional information, or contact Keach Sasamori at >[log in to unmask] or 847-509-9700 ext.5315 >----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------