While I feel performing a test spot is ultra crucial, I don’t feel taping one off is. Let me explain:

For years I have been taping off a spot and judging how the test spot came out by the fine line where the tape covered vs didn’t cover. It gives a great indication of what your process will do. My problem with taping and running a buffer over that tape line is 2 things.
1) What I like to call adhesive migration. This is when some of the adhesive from the tape actually pulls out from underneath during the buffing process and begins to affect the pad/buffing liquid performance.
2) The buffing liquid builds up right on the edge and gives you that line when the tape is removed. I find myself having to rub/remove that area excessively, possibly creating towel induced marring thus working backwards.

So I have stopped taping my test spots. To judge how my test spot came out I simply make a mental line of where to buff to. Then I fold a 16x16 in half then I fold in half again the same way giving myself a 4x16 towel that I use to lay down on the paint as my border. Then I simply take my light of choice and compare to see how my test spot came out. It’s much easier and a bit safer I believe. While it may not look as dramatic I feel this is a better method.

While taping when polishing is necessary the less you have to do the better. Most areas we tape don’t get the harsh treatment from a buffer as a test spot does so the above issues may not be as noticeable or even a problem.

I hope this may help someone.

Thoughts?