Blue masking tape: How long to leave on?
That happened to me this summer as well.
I think I solved the problem by changing primers. I was painting over bare wood and used Zinsser's Bullseye 123 as the primer, followed by two top coats of a exterior flat pretinted brown. I had a heck of a time with the paint pulling off with the tape, and when the paint pulled off, it left bare exposed wood, not primer. That indicated to me that the problem was at the wood/primer interface, not the primer/paint interface.
Next time, I used a local paint company's (Northern Paint) exterior latex primer and two top coats of the same exterior flat pretinted brown, and NONE of the paint pulled off with the tape.
I think the problem is that Zinsser's Bullseye 123 is not only real sticky, but it sticks better to the painter's masking tape than it does to the bare wood (or other substrates, too). I was painting window frames on different sides of my building, and some of the difference could have been due to the different exposure to the Sun, too. Also, when using the Bullseye 123 we had good weather and we top coated only a few hours after priming. With the locally made primer, it rained a few hours after we primed, so we didn't top coat till the following Monday (cuz my nephew was doing the work). I really don't see how the rain or waiting period would have affected the problem, tho. I'm thinking the biggest hunk of the problem was from using a primer that stuck better to the tape and itself than it did the bare wood. The other primer didn't do that, so maybe it doesn't stick to itself or the masking tape as well.
I always pull the tape off as soon as we finish the second top coat. We did that in both cases here, too. I can see that this would help because perhaps the second coat hadn't even formed a film when we pulled the tape off, so the second coat at least didn't contribute to the problem. But, me thinks the problem is more with the primer than the paint anyhow, and so my best guess is that asking how long to leave the tape on is the wrong question. I think if you use a different primer, it won't matter how long you leave the tape on, you'll get equally better results.
Try a different primer.
Last edited by Nestor_Kelebay; 08-13-2008 at 12:05 AM.