I use a tape I found at work. I don't know what they use it for here, I don't think it's for masking. It's a Teflon tape, not like plumber's tape. It's adhesive backed, not too strong or too weak. It's translucent so I can really see if it's stuck down good. And it's quite pliable. I lay it down on a piece of glass and cut off strips about 1/8" or so wide. It bends around inside and outside curves real well. And it's got a clean, sharp edge.