Isn't the 72 hours before bake a requirement for polyimide instead of FR4? Alain Savard, B.Sc. Chemical Process Analyst CAE Electronics Ltd. e-mail: [log in to unmask] -----Original Message----- From: Dewey Whittaker 1. Typically, for multi-layer (6-8 layers), FR4, SMT boards stored in an air conditioned environment at about 50+/- 10% RH, how many months would you allow to pass before you would recommend baking them prior to reflow? 2. What would be your bake cycle? Thanks, Charlie B. #################################### Without knowing any other variables and being conservative,72 hours is your window for the Aerospace Industry. Dewey -- Dewey Whittaker ############################################################## 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 ##############################################################