I thought most people applied heat when vacuum drying - the greater the vacuum, the lower the boiling piont of the water. Thus the water in the pores become highly agitated and evaporates at a lower temperature, and with no oxidation of the leads/pads, and slower intermetallic formation. The pores gradually become evacuated, then the vacuum cabinet can be backfilled with dry nitrogen gas, filling the pores with dry gas rather than moist air. Hope that made sense. It can be overdoing it a bit though, depending on what level of technology you are working on. Besides, someone was telling me the other day that within the first two hours of being open to the environment, the board will probably have more than half its old level of moisture back again. If you take a batch out of bake in the early morning, and don't flow / reflow the last of them until afternoon, moisture based problems may still occur. Therefore improved moisture extraction should be coupled with improved procedures. Hope this helps, Regards, Richard Tilbrook ############################################################## 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 Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################