The "B" Stage always contains moisture and solvents and may be necesssary to achieve flow of the epoxy resin in the prepreg. Evacuating the prepreg often times produces thick dry laminations. The main thing that should be done is to keep the solvents and moisture dissolved and finely dispersed in the resin in the prepreg during lamination and prevent these from forming little bubbles that coalesce to form laminate voids. Suggest that you do a few lamination tests to try to eliminate the laminate voids. I assume you are not using a vacuum assist press and that you are using a kiss cycle before applyiing full pressure. (1) Use a 25 psi kiss pressure before going to full pressure instead of the 15 psi (2) If you are usng the kiss pressure and going to full pressure at somewhere around 110oC internal package temperature, try backing off and go use the temperature to apply full pressure at the tempetatures of 80, 90 and 100oC. Also try a one-step laminating process which is to apply full pressure immediately after placing the package onto the hot platen. (3) If you are using a vacuum assist press, I would also suggest that you do (2) above. Of course, look for voids after the tests above Several things that are missing from you failure report are: Type of press Heat rise rate Kiss or no kiss Type of prepreg, glass style, gel time, scale flow Kiss pressure Laminating pressure Area of panel where greatest laminate void density appears. All of these affect the prossibility of the formation of laminate voids. and would give the failure analyst a better chance. If you want give me a call at the number below. Phil Hinton [log in to unmask] 520-745-1013