Blockout Red 421 is an inexpensive, water-based solution used as a plastisol, UV and solvent-based ink barrier. This bright red blockout and touchup liquid has just the right viscosity to spread easily over every mesh count. Solvent-enhanced agents greatly reduce dry times, yet the formula is non-flammable. Blockout Red 421 is water-soluble therefore, it is not intended for use with water-based inks.
Bottom Line: Hey, not every stencil will be defect-free. Touch-up & go!
Using a water-resistant emulsion for water-based inks? Since Blockout Red 421 isn't made for WB ink, use your emulsion for touching up, but remember to expose it after drying to hold up during printing.