First, I can only assume that the "selective solder reflow" was an SMT assembly, not a flux and wave solder operation. If flux is added to the board and then subsequently washed off, all bets are off! Secondly, I question the need for "oxidation arrest paper" for OSP boards exposed to a selective solder reflow. From the inforamtion provided by Enthone, the supplier of ENTEK-106A, the first thermal cycle actually increases the chemical resistance of the OSP that covers unmasked copper. The reflowed solder joints have already removed the OSP and replaced it with Sn/Pb. The OSP coating can normally withstand up to 8 thermal cycles before it becomes too thin to protect the copper. Therefore, why add unnecessary storage costs to the process? If you are concerned with environmental intrusion while in storage, try packaging the boards in plastic bags (e.g. the bags in which the boards were shipped to you from the PCB fabricator) and place them back on the shelf. The additional covering also provides a scratch protector against normal handling damage prior to the second assembly process. Just some food for thought. Bill Fabry Plantronics, Inc. [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: [TECHNET] ASSY -OSP-Preserving Solderability Author: "TechNet Mail Forum." <[log in to unmask]> at INTERNET