Has anyone had any experience with Solder Stop (water soluble mask) affecting LPI adhesion around pad openings on Groundplanes. Typically adhesion issues almost always relate back to inadequate surface prep during the board manufacturing process. I had to "see it to believe it". We have reviewed every step of the process and cannot find any disconnects. We have only one Customer experiencing this problem. They have used the same Solder Stop for approx 5-6 yrs. At 1st it was believed that the peeling didn't occur until after Wave Solder. However, they had coated some bds and allowed them to set over the weekend and after washing them off found the peeling mask. We tape test all boards at our facility per IPC-TM-650 procedure. There has been no evidence of peeling at all. After visiting with the Customer it seems that the time the Solder Stop is on the bds (i.e. longer than 2 days) determines whether or not peeling will occur. The peeling is always on pad openings which are on Copper groundplanes. We have no evidence of any peeling on pads which are surrounded by FR4. The peeling is usually limited to an area concentric to the mask opening and extends 5- 30 mils into the surrounding mask. We have run tests at one of our other facilities consisting of running numerous bds across the wave solder at different preheat and solder pot temps (we even matched the temperatures the Customer with the issue is using) with no evidence of peel. The customer is adding approx 1 cup of water to 1 Gal of Solder Stop to aid in flow. It was requested not to refer to the Material's manufacturer until we have additional data. Any suggestions or help you can provide will be greatly appreciated. Thanks, Craig --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------