I don't think there is any value given for "allowable" moisture prior to reflow. Perhaps whoever said to bake 5 hrs at 120C to determine moisture content would be the one to determine a value. I have seen some boards that had many layers and ground planes that needed a much longer bake - with vacuum to get the moisture out so as not to degrade during assembly. Susan Mansilla Robisan Lab --------------------------------------------------------------------------------- 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 e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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 ---------------------------------------------------------------------------------