Jim Mc Neal asked when "tented" vias are required with LPI soldremask. Here (Aerojet) our application is space / vacume environment. _When_ we require a soldermask (smt parts bonded to pwb _with_ vias under the part) we will tent the via. on all other applications our designs are pads-only (so we don't need _any_ soldermask) We tent so that we don't entrap air (or contaminants) in the pwb. HTH, Bill Gaines AeroJet (for $) 1100 Hollyvale, Azusa, Calif. 91702-0298 IEPS (for info) [log in to unmask] IHPVA (for speed & fun) P.O. Box 51255, IN, IN 46251-0255 SCCA (for trophys) Solo II (818-988-RACE)