HumiTape from Humiseal works well for us + the adhesive is silicone free (Kapton tape isn't) which is a plus if you're using UR coatings...check out the HT600 ESD safe version. From their webpage: HumiSeal HT500 and HT600: High performance masking tapes will protect finger contacts, connectors, terminals, unsealed components, etc., from conformal coatings. Tape is a polyester film with rubber resin and pressure sensitive adhesive. It is silicone free and contains no chemical release coat. As a result there is no residue when tape is removed. Available by the roll in a variety of widths, and as dots, squares and rectangles in a variety of sizes as well as in custom shapes. HumiSeal HT600 is ESD safe to protect static sensitive components. Regards, Mike Sewell