Hi everybody, Can someone help me with the following: I am having problems with the solder quality after passing MST components by Forced Convection Ovens. The pads are gold platted and the solder is Delta Qualitek No Clean 63 37. The fillets are ok, the wetting is there but there are some yellow residues in top of the solder joints. What is the root cause?? Could it be Flux residues??? Or reaction between Solder paste and GOLD?? Or what?? Please help me out this is very important. Ruben E. Irizarry Operations Engineer ################################################################ TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################