If there is a noticeable change in the appearance of the solder mask after wave soldering, this is a sure sign that something is wrong! Possibilities are: 1. The solder mask was not processed correctly in the first place. If your copper circuitry boards are hot air solder leveled, that usually indicates that the mask was processed okay, or nearly so (incorrectly processed masks will "blow apart" during the hot air leveling process). 2. If the mask is processed correctly, then the problem can lie in the assembly process itself. Possibilities would include: A. Excessive solder temp or excessive dwell time B. Excessive preheat C. Aggressive flux or incompatible flux D. Excessive exposure to the post clean process (especially alkaline cleaners) Under correct solder mask processing and correct assembly, there are any number of solder masks (LPI and dry films) that should work just fine. Regards, Larry Fisher Dexter Electronic Materials [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************