That is 'correct'. Ahne. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer Sent: 5 May, 2014 05:15 To: [log in to unmask] Subject: Re: [TN] Solder Mask over Tin Lead Plating This was common practice in the days before SMT. The masks used at the time would ripple where the tracks were reflowed, but didn't crack. Still made it through the solder wave just fine, and no problem with hand soldering either. I sometimes still see this today with single sided wave soldered boards such as cheap consumer audio and power supplies. "Correct" is what works for your application. Inherently, there is no reliability issue with this construct. Wayne Thayer -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ramakrishnan Saravanan Sent: Sunday, May 04, 2014 4:18 AM To: [log in to unmask] Subject: [TN] Solder Mask over Tin Lead Plating Hi, We received few PCBs from an European PCB manufacturer for Aerospace Industry. I am surprised to see Solder Mask is applied over tin lead plated tracks. My understanding is if u do reflow , the solder under the mask will melt and affect the mask. The correct method is applying Soldermask over bare copper isn't?. Kindly advise. regards, R.Saravanan ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________