It is either, the coating too thick, and can be eliminated by spraying a thin coat and observe or what I really think it is, the potting is not fully cured and is out gassing creating bubbles. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken Sent: Tuesday, January 24, 2006 3:15 PM To: [log in to unmask] Subject: Re: [TN] Conformal Coat (Urethane) & bubbles Kelly, I have to ask, do you really care? What purpose does conformal coating on top of potting compound do? It doesn't appear that it violates any electrical spacing or opens up any base metal to the environment. If it were me I think I'd just leave it alone and live with the bubbles. Of course that just my .02's worth Kennyb -----Original Message----- From: Kelly Morris [mailto:[log in to unmask]] Sent: Tuesday, January 24, 2006 10:23 AM To: [log in to unmask] Subject: Re: [TN] Conforma Coat (Urethane) & bubbles >We've got a problem here, where we're hand spraying a urethane conformal >coat on over a rectangular inductor. >The inductor body is a plastic tube, with potting to fill. >The top is not always flat (sometimes concave). >The problem is that bubbles appear in the conformal coat on the potted >surface, sometimes right after bake and sometimes days after. > >Any ideas on what the root cause is and how to prevent the bubbles? > --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------