In answer to your question regarding the overcured boards, you need to be concerned also with the adhesion of the solder mask and breakdown of the solder mask. Regarding the laminate, an increased cure should not affect any of the electrical properties you mentioned. Copper peel strength could be degraded, and flex strength of the laminate will be affected. The fire retarding properties will not be affected because the fire retarding properties come from inert ingredients added to the resin. There is a covalent bond between these ingredients which will not be broke by over-curing. David Mander Sun Coast Supply Longwood, FL 800-264-1250 [log in to unmask]