Hi Suzanne - I have had white residue problems similar to yours but under different circumstances. We found white residue on the pads/solder fillets after a saponified water wash. The soldering process was RMA wave flux, no nitrogen, wave solder process. The white residue was NOT saponifier (we were using an Alpha product, basically a soap). We found (after an enormously long investigation) that the white residue was due to high water wash temperatures (greater than 150 F). We were getting some type of lead - wash temperature reaction, most likely related to the saponifier chemistry also, due to a run away heater. The problem was corrected by replacing the heaters and improving the temperature controls. You are using a different cleaning system than we did but you may want to check out the temperature issues. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: White residue/lead oxide Author: [log in to unmask] at ccmgw1 Date: 5/7/96 12:16 PM We have a white residue problem at another division that has been analyzed using FTIR and SEM EDAX that has shown it to be lead oxide. The white residue is located on pads/solder fillets. The following process is used: a. Yokota flow solder (preheat 220F topside, 495F solder pot (less than 3 seconds), conveyor speed 3.5 ft/min) b. Kester 197 foam fluxer (rma) c. Cleaner is Bioact EC7R in a Ney spray under immersion or ECD batch diswasher. Temperature of EC7R 90-95F, Rinse waters 130F. The white residue is observed after cleaning and is insoluble in alcohol water/EC7R. Any input on things to look for would be greatly appreciated. We are running tests at other divisions with different flux chemistries/board design/process parameters. [log in to unmask]