We're having contamination problem which is impacting our conformal coating process. Here's the story: We use "Kapton" style tape to guard the edges of a circuit board while the board is processed in our wave solder machine. The board/tape reaches a peak temperature of 220C for three seconds. The temperature ramp keeps the board above 120C for approximately three minutes. After passing through the wave solder machine, the board is allowed to cool to room temperature. The tape is then removed. No visible residue is left on the board. However, when we attempt to conformal coat the board, the coating is repelled from areas where the tape was applied. No manner of cleaning (alcohol, water, acetone...) will remove the contamination and allow the conformal coat to bond to the board. Are you aware of what the source of contamination could be? We have managed to rule out flux. Boards have been taped and tested prior to heating and no residue was found. Four different brands of tape were tested with identically poor results. Ceramic edge stiffeners have been tried. The edge stiffeners clamp mechanically over the edges of the board. Some contamination was found when edge stiffeners were used, though not as much as with the tape. Boards run without protection show no contamination. I would appreciate any insight you could provide into the nature of ############################################################## 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 ##############################################################