Dear kgchafin - name please? I am not qualified to comment upon electrical issues with vias but, on behalf of conformal coating users, it should be bourne in mind that coating methods including selective, will permit some material penetration through the via and of course, coat or plug the via. With selective coating, the idea is to minimise masking but if there are components on the opposite side that should not be coated, there is a high probability they will be contaminated as the coating comes thru the via. We therefore generally recommend that via's be blinded by whatever means thought best. Graham Naisbitt [log in to unmask] Concoat Ltd Alasan House, Albany Park Camberley GU15 2PL UK -----Original Message----- From: [log in to unmask] <[log in to unmask]> To: [log in to unmask] <[log in to unmask]>