The sooner the better. This will allow the edge to relax somewhat before the paint has reached full hardness.
When you pull the tape, don't pull it at a 90 degree angle from the panel. This can cause the paint to peel. Pull the tape back over it's self, this cuts the paint with less chance of peeling it.
I just painted my engine with Omni single stage utethane over epoxy primer. The Technical Data Sheet for this particular paint says "Tape Time: 12-hours" (NOTE: different paints have different requirements - get & read the proper TDS for the paint you're using ). Also, tear the tape off slowly and at an angle away from the masking area so it doesn't lift the tape off, it peels it back. What the TDS DOESN'T say, are you supposed to remove the tape BEFORE 12-hours or AFTER 12-hours. I waited the 12-hours and removed it without a problem.
FYI: What Tape time means in the TDS is how long before you can tape on the newly applied paint, NOT how long to leave tape TagMan.
When I worked for a body shop a lifetime ago I was taught to make a "test panel", usually a junk fender or door prepped just like the repair; sanding, priming, paper, tape, paint. When you thought it was time to pull tape you tried the test panel first.
i will be painting , taping , painting again then peeling tape off. good to know when to tape after first coat and take off when done. thanks
I have some photos of a job I taped off on page 7 of this thread: https://www.jalopyjournal.com/forum...nt-that-fixtures-and-taping-technics.1008403/ I used solid color urethane enamel.