I just bought a basic screenprinting kit, and the directions say to mask off the inner and outer edges of the screen using "water resistant masking tape". I have blue painters tape, but it doesn't specifically say that its water resistant. Is this okay to use? I'm using a totally water-based method. Secondly, should I replace the tape with every new run or just leave it on there as long as it lasts?
I use either cheap clear packing tape (99 cent Target brand) or brown packing tape, whichever is around.
Not sure exactly what your second question is, but... yes, if you are doing a run, then stopping to wash out, reclaim, etc., you should remove the tape. If you're waiting more than a few minutes to start another run, you should get the ink off and out, or else it will dry. This might actually be considered the same print run, depending.
Jer's right; Masking tape falls apart, and the bits get mixed in the ink. It sucks completely. It is also too rough for the squeegee to glide on. Use a thin slick 2" packing tape, some of this stuff comes apart (the glue) when you strip it, so find a good brand.
Personally, I tape in to about 1" of the image, or at least so the edges of the squeegee are running on tape. Then cleanup is a snap, just pull a thick flood before the last print, then a print and the ink will scrape clean and sit on tape. Strip the tape after scraping up the puddle, you will have hardly anything to clean.
If you are reclaiming the screen, definately remove the tape. If you are cleaning the ink out with the intention of printing agian, you might be able to leave the tape, just make sure you have cleaned the ink thoroughly from the image or you will be buying a new screen pretty quick because your old one is clogged with ink that won't come out.
Mark, if you can, wet the screen on the back for a few minutes before you pull the tape. this softens the grip and lets the glue stay with the tape.
If you can't wet it, try and not leave the tape on for any length of time, peel fresh. Also, I found if you peel it back (parallel to the tape) instead of pulling up, it doesn't leave a trail of slug slime.