Hi All You Sherlock Holmeses (sp?) out there, I have a strange mystery which intermittently appears, so put on your Sherlock Holmes' hat and grab Dr. Watson. When we wave flow solder one particular board, during our cleaning process (which can be moments afterwards), we might see tin and lead oxides covering/surrounding the pins. When we do see it, it's real bad. DeOxIt cleans it off well. Any better corrosion removal suggestions out there? My ultimate goal is to prevent it (well duh). We use Kester 186 and 186-18 RMA flux, it's a Kester 60/40 tin lead solder in an old Hollis wave flow soldering machine. We also use a latex solder mask, how that might cause corrosion I don't know but there it is. The only remaining culprit might be very old (from Hollis) tinning oil, aka dross inhibiting fluid. The solder is tested by Kester, Option C, and are well within MIL-STD-2000 & J-STD-001 specs for the 12 contaminants they check. The boards are fluxed by brushing it on with a camel hair brush and then baked in an oven - the wave only has bottom side preheat. (I'm working on reviving either the Hollis wave or the on-board foam fluxer, honest.) Since we are a low volume shop we might run the wave two or three days a week and the remaining days it is turned off. Is something wrong with the startup routine? The corrosion shows up around the pads of tin & gold plated connectors. It is one of those gremlins which appears and disappears without any apparent pattern, just when you think it is gone . . . bam! The last analysis also showed sulfur - don't know if that's an essential piece to the puzzle or not. We are checking to make sure the boards aren't corroded before soldering but right now that's an assumption. At least, a visual inspection doesn't show anything obvious. Anybody seen and defeated this Moriarty before? We've not a moment to lose! Hans ~~~~~~~~ Hans M. Hinners WR-ALC/LYPME Bldg. 640 Materials Engineer 380 Second Street, Suite 104 Manufacturing Eng. Sec. Robins AFB GA 31098-1638 912-926-1970 (Voice) 468 - 1970 (DSN) 912-926-7974 (Fax) [log in to unmask] ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################