Catspit Productions offers a tested and approved water based textile ink for screen printing shirts and other garments. Water based inks are perfect for the soft hand feel that many consumers want today. It is true that you can print soft hand prints with plastisol inks, but that will tend to limit you to halftones or lighter colored garments. And there is only so soft a plastisol print can feel when there are considerable layers of multi colored ink built up. And the way plastisol ink tends to sit on top of the fabrics knit also makes it a challenge to print over seams, pockets, collars or stitching of any kind. It can produce unsightly build up on uneven surfaces. But water based inks are excellent for this purpose because of their tendency to be absorbed into the fabric.
Water based printing will demand a different set of screens and even your art can be designed accordingly. Artwork creation, especially for halftones, will be a whole new animal due to the way the ink is absorbed into the garment fabric. Obviously this in turn requires particular screens and mesh counts. Making very small and detailed artwork with tiny stencil openings can promote ink drying on press. Therefore artwork for water based work is done specifically for it. Distressed and textured prints or loose, hand sketched art, blends well with any irregularities in printing due to ink flow issues. Just as it is with standard plastisol screen printing, your artwork can make or break you.
Remember to use an emulsion that is designed for water based inks and solvents. A special additive can be used with some emulsions to protect the stencil from water based discharge inks. You can reclaim any screens used for water based printing the usual way but make sure to clean the screen of any ink immediately after use. If you do not, the water based ink can clog the mesh permanently. Also keep in mind these inks are much thinner than plastisol inks and will not need as much squeegee pressure when printing.
And one last note: if you plan on doing any large volume commercial printing with water based inks, you should seriously consider a decent size forced air belt dryer. The larger oven chamber will facilitate the curing process and ensure consistency throughout your print run. Just because water based inks are said to "air dry" they most often need to be heat set to properly cure in commercial applications.