Yes, by using a Co2 laser at low power settings. Most, if not all maskings can be removed from pads and traces with a laser. The mask will be ablated very easily, and will not harm the metal of the circuitry, as long as very low power / pulses are used. After laser ablation, process your boards (unpopulated) through a final clean / acid rinse to remove any remaining debris. Any small soldermask touchups can be re-applied by hand. If the laser process (Program & parameters) is setup correctly, you may not need any touchup at all. Major touchup could be reapplied using a new 'Rework' artwork / screening / LPI process. Not sure of any chemicals that can be used. Dave Simonik Sanmina-SCI Owego NY Division -----Original Message----- From: - Bogert [mailto:[log in to unmask]] Sent: Wednesday, September 15, 2004 5:45 AM To: [log in to unmask] Subject: LPI Solder Mask on Class 3 Product; Can it be removed? September 15, 2004 Does anyone know of a method to remove fully cured LPI solder mask (IPC-SM-840, Class 3 product) from an FR-4 PWB without damaging the PWB or otherwise creating possible condition for growing dendrites? If chemicals can be used, are they non-conductive? If solder mask needs to be touched up because of missing solder mask, --------------------------------------------------- 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 ----------------------------------------------------- how do folks do this? ____________________________________________________________________________ _ Scanned by Sanmina-SCI eShield ____________________________________________________________________________ _ --------------------------------------------------- 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 -----------------------------------------------------