Steve, If you vacuum oven your boards (boiling off and evacuating any moisture), then open them into an environment, perhaps 22deg.C and 60%RH, won't the boards quickly absorb the moisture in that environment? If you then manufacture the boards, then ATE and inspect them, then conformal coat / dip them, you'll be sealing moisture in. I only ask because I am researching into moisture sensitive components, and one of the options is to put the components into a vacuum (oven / chamber). I am concerned that putting non-hermetically sealed electronics components (boards or devices) into a vacuum oven leads to little or no advantage, and only the acceleration of intermetallic formations between copper and tinned layer as a result. My question (finally) is would this be the case? Or would the rate of absorption be so slow that it wouldn't really matter? 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################