To mask things, before cutting/engraving, I like to use vinyl lettering transfer tape. In particular I recommend RTape Conform 4075RLA Transfer Tape. It is categorized as high tack but it seems to be more of a medium tack, which means it holds fairly well but isn’t very difficult to remove. I buy 8.5" wide rolls from SignWarehouse. At 100 yds it lasts a good while.
12 x 300' Roll of Clear Transfer Tape for Vinyl, Made in America, Premium-Grade Vinyl Transfer Tape for Cricut Vinyl Crafts, Decals, and Letters : Arts, Crafts & Sewing
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PREMIUM TRANSFER TAPE: This 18 inch wide x 300 foot long (100 yards) roll of vinyl transfer tape paper is ideal for craft die cutters like Cricut
Transfer Tape for Vinyl, 18 inch x 300 feet, Paper with Layflat Adhesive. American-Made Application Tape for Craft Cutters and Sign Makers
Mirror Acrylic Sheet With 3M 300LSE Adhesive Transfer Tape Backing. Sheet is 12in X20in 1/8in Thick, Laser Safe
Transfer Tape for Vinyl, 18 inch x 300 feet, Paper with Layflat Adhesive. American-Made Application Tape for Craft Cutters and Sign Makers : Arts, Crafts & Sewing
My take on the laser printer toner transfer technique : r/3Dprinting
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