Don't use those circuits. That's the short answer. What is wrong with putting a simple pressure-sensitive adhesive backed insulator over those areas? I have also used Type UR Conformal Coat per IPC-CC-830 built up to 5 mils thickness in those areas as a temporary fix until the PB can be re-designed correctly. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting Sent: Wednesday, August 15, 2007 7:59 AM To: [log in to unmask] Subject: [TN] Solder mask as an insulator Let me start with, I know that we should not rely on the LPI solder mask as an insulator. So I need recommendations for a simple and cost effective solution. Problem parameters; 0.062 thick FR-4 with 2 oz copper and LPI mask. PTH components laying on traces that go under the parts. PTH parts are shorting to the traces. Our fab house is against adding a second layer of LPI mask. On face value a second layer sounds good and easy, but I know there are issues too long to list. Short of raising the components above the board, applying an insulator under the components or a new board layout is there a better way of preventing this shorting problem? Thanks in advance. Phil Nutting Design for Manufacturing Engineer Kaiser Systems, Inc. 126 Sohier Road Beverly, MA 01915 voice: 978-922-9300 x1310 fax: 978-922-8374 e-mail: [log in to unmask] www.kaisersystems.com --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 -----------------------------------------------------