Our experience with this issues has not been totally positive. Although one may successfully protect the actual bare board (assuming certain minimum thicknesses of soldermask), any exposed copper on components still are subject to corrosion. A second issue specifically on SMT boards is the height of the soldermask. If the mask is too high, it creates problems at assembly. If it is not thick enough over the corners of isolated circuits, it does not afford adequate protection. A third issue is handling vias under components. LPI does not tent well enough to protect the via. HASL prior to plugging, especially on mixed technology boards, creates assembly issues. Successfully 100% plugging vias with mask is an artform. I would not recommend soldermask as an alternative to conformal coating. ---------- From: [log in to unmask] To: [log in to unmask] Subject: [TN] ASSY: Soldermask vs conformal coat