Plugging vias with LPI typically leaves an air pocket in the center of some of the vias, half way between the top and bottom surfaces. Given this condition, some of these vias will develop a hole in the LPI plug as they are being cured. The smaller the hole, the greater the chances of liquid entrapment, particularly when the board is warm and exposed to a cooler liquid. Depending on the nature of the entrapped liquid, a field failure caused by an intermittent via will most likely be in your future. Depending on your artwork requirements, LPI offers other advantages like finer resolution and lower cost. I would seriously consider switching to LPI if you can avoid depending on it to 100% plug your vias. Norm Dill ############################################################## 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. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################