Peter, I would add one more concern when choosing a coating and that is maximum expected temperature. The Tg of various coatings will determine which can be used for expected temperatures. David A. Douthit Manager LoCan LLC [log in to unmask] wrote: > Hi, Matt, > > The commonly used coatings are either Acrylics, like Humiseal 1B31 which we > use, Urethanes or Epoxies. All three have the same good resistance to > moisture and salt fog, but the difference between them is that Acrylics are > not very chemical resistant (which makes them great for rework), Urethanes > are more difficult to rework and need much more sggressive stripping agents > to remove them, and Epoxies are darned near impossible to shift. I remember > the days of PC54, which was the common coating for military PCBA's up til > the early 80's, and repairing boards nicely was a major pain. > > If it's purely Humidity and Salt Fog you're up against, use an acrylic > conformal coating. It's easily applied by brushing, dipping or spraying. > > Peter > > "Gray, Matthew D HS-SNS" <[log in to unmask]> 22/05/2003 09:54 PM > Sent by: TechNet <[log in to unmask]> > > Please respond to "TechNet E-Mail Forum."; Please respond to "Gray, Matthew > D HS-SNS" > > To: [log in to unmask] > cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) > Subject: [TN] Conformal Coating Application Method for BGA > > Hello - > > I am requesting feedback to material and processes that have provided > environmental performance protection for BGAs and other large array > packages. The performance environment of consideration is corrosion and > humidity. > > Can users provide particular details regarding application process spray > (inclusion of steps used for flood/fill/etc), dip, other, and material that > has provided a high amount of coverage and ability to protect electrical > connections and components in humidity and salt fog environments. Ideally, > these materials are below the parylene step. All feedback is appreciated. > > Regards - Matt > > --------------------------------------------------- > 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/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > ----------------------------------------------------- > > [This e-mail is confidential and may also be privileged. If you are not the > intended recipient, please delete it and notify us immediately; you should > not copy or use it for any purpose, nor disclose its contents to any other > person. Thank you.] > > --------------------------------------------------- > 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/html/forum.htm 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------