Sorry, Cleaning process is vapor degreaser, then terpene. The residues are not white. As far as differences between first pass and second, there were none. Both passes are cleaned in exact manner. Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)212-0844 cell [log in to unmask] -----Original Message----- From: Blomberg, Rainer (FL51) [mailto:[log in to unmask]] Sent: Wednesday, March 09, 2005 3:16 PM To: TechNet E-Mail Forum; Jason Gregory Subject: RE: [TN] Cleaning residues off of PCB Try Axarel 2200 from Petroferm (http://www.petroferm.com/PTF-053/clean/clean_frm.html). This is what we use for tough flux removal cases after hand-soldering. You didn't mention what your cleaning solvent/process was. Are these residues white? If the first pass looked good, what was added afterward? Could these be evaporative residues from your cleaning solvent? > Rainer G. Blomberg > Honeywell -Space Systems Clearwater > Staff Production Engineer (727) 539-5534 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jason Gregory Sent: Wednesday, March 09, 2005 3:56 PM To: [log in to unmask] Subject: [TN] Cleaning residues off of PCB Hello all, We have some boards that I am requiring some advice on cleaning residues. The PCBs were soldered with SN96 (Sn96.5/Ag3.5). The first pass of the boards look great. However, the second pass looked very suspicious. We are seeing residue that looks like dried, puddled flux residue around most of the leads. The areas mostly affected are multi-leaded components and there is no evidence of this residue in open (non-populated) areas of the board. If we take something like a probe or tweezers and move them along the areas of concern, then it flakes off, but not real easily. I am afraid to do this in fear of damaging the laminate (these are expensive boards). We have tried re-fluxing them with aggressive RMA flux and re-reflowing them, but to no avail. I have just tried soaking them, for 15 minutes, in a 50/50 solution of distilled white vinegar and DI water, but again, to no avail. Does anyone have any suggestions as to something else to use that's aggressive, but not damaging to polyimide (or the solder joints)? TIA, Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)212-0844 cell [log in to unmask] --------------------------------------------------- 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 -----------------------------------------------------