Hi technos, and big thanks for the interest in my problem. Now, I tried to follow all the leads, I checked the solder mask, I ruled out the contamination, since the problem shows on each and every board, checked for oily residues, etc. To clarify, the problem pads show no sign of having been in contact with the solder, they are like before waving. So I still can't put the finger on the cause. However, by hand spraying the bottoms, or running the foam fluxer at max, we reduced the number of problems. We even get, from time to time, fully soldered boards. Maybe the boards have gone through some thermal cycling that made the intermetallics grow, or the pads are oxidized for some reason. Maybe a bad batch. I'm sure that a stronger flux would solder very well, but why this deviation from the regular process, since we are talking regular boards? So, the follow up question is: what should I do to avoid that the problem reappear while running a future job, eventually high volume? Thanks, Ioan --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------