I have a lot of water based ink left over from projects I did when I was silkscreening on paper.
Can I use this ink to silkscreen on tee shirts? Or do I have to buy different ink?
I feel silly.
You could use it to print on shirts. There is generally a difference between textile and paper water-based screenprinting ink, but nothing so substantial that you couldn't do it just to recover the ink. As far as water-based goes, it lacks the opacity of Plastisol inks—which are acrylic-based—and cures itself. So you've got to move a little faster with it. It'll work though, its worth a shot. But yes, there are water-based screen-printing inks that textile printers use all the time. A lot nicer to breathe.
I will say that i've had problems crossing plastisol emulsion with water-based inks and vice versa.
Am I right to assume that by water-based inks, you mean waterborne acrylic emulsion that is waterproof when dry, right? Not a soluble gum based paint like gouache or poster tempera?
If that is the case it should be compatible with most brands of artists acrylic paints and inks. You may need to add an elastic medium to prevent it from cracking on garments. Ceramcoat Textile Medium is good if you are producing a relatively small volume. It's available at craft stores. For larger volumes I'm sure a commercial silkscreen supply house can provide an equivalent. Of course adding clear acrylic medium of any kind will increase transparency of the inks, so this is generally only a viable solution on white shirts.
Do a wash test first.
Poster ink is thinner than textile ink. You'll get an image but it won't be very opaque (speaking from experience).
Its standard water based silkscreen ink.
Do I have to cure it? If so, how?
Maybe, just don't throw our t-shirts in with the whites the first couple times they are washed. :¬)
Once it's dry you can try tossing in the dryer to cure. Or, if you're a masochist, sit there with a towel and an iron to cure every shirt.
I put them in the oven to cure :)
Haley, Do you recommend glazing before they go in the oven? :-)