Hi Jim - A mild bake to dehumidify a board isn't unreasonable, but some of the times and temperatures you are mentioning are a mite to the extreme. Bake cycles such as these can promote a fair amount of surface oxide formation and worst of all, considerable intermetallic growth at the copper/tin interface. None of this is going to improve solderability, and it may have a very negative effect in the long term. Ideally, find the cause, eliminate it, then reduce or eliminate the bake and get on with life. There are several reasons why boards delaminate, water type moisture being one of them. The others include: solvent type moisture, which often tends to cross link with the resin; poor surface prep on the internal layer surfaces; improper storage or preconditioning of the prepreg layers; and incomplete cure of the laminate structure. I would expect the board fabricator to have tight control on his prepreg handling. I'd also expect to see a post laminate bake in his process, just after final cleaning and prior to solder mask (if used). May I suggest you invest in some DSC or TMA testing on samples of the boards in the "as received" condition? If the problem is moisture or resin cure state, this testing should help isolate it. The laminate manufacturer, via the board supplier, should be able to provide Tg data and standard DSC or TMA plots of his materials behavior to correlate with the test results. Encapsulated microsections of the delaminated area can tell a lot about its nature as well. At what elevation did the delamination occur (prepreg, laminate, metal surface, etc.)? Did it delaminate between two plies of glass mat or did it tear up a glass mat? The next area to take a close look at is how the boards are being handled and shipped. Reusable vapor barrier containers, bags, etc., can go a long ways toward avoiding the pickup of environmental moistures. This is particularly a problem in coastal areas and the southern states. Got to remember that board is honeycombed with micro-capillaries that will pick up moisture fairly rapidly if allowed. There can be a lot of available moisture in trucks, shipping docks, stock rooms, etc. Good luck - Kelly ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################