Effectively using water-based inks involves careful preparation, application, and post-processing to achieve optimal results, especially in screen printing. Here's a step-by-step guide:
1. Preparation and Materials
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Ink Selection: Choose the right water-based ink for your project. Options include:
- Standard Water-Based Inks: Suitable for light-colored fabrics.
- High Opacity Water-Based Inks: Ideal for dark fabrics, often requiring fewer layers than standard inks.
- Discharge Inks: Remove the existing dye from the fabric, replacing it with the ink color, resulting in a very soft feel.
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Fabric Selection: Water-based inks work best on natural fibers like cotton, linen, and rayon. Consider the fabric color and weave.
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Screen Preparation:
- Mesh Count: Use a higher mesh count (110-160 for standard inks, 160-230 for detailed designs) for better ink flow and detail. A lower viscosity of water-based inks necessitates finer mesh.
- Emulsion: Use a water-resistant emulsion designed for water-based inks to prevent breakdown during printing.
2. Printing Process
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Applying Adhesive: Use pallet adhesive to keep the fabric from moving during the process.
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Inking the Screen: Apply a bead of ink along one edge of the screen.
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Flooding the Screen: Before each print, flood the screen with ink. This means using the squeegee to evenly distribute the ink across the design without applying pressure. This keeps the mesh open and prevents the ink from drying in the screen.
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Printing: Apply firm, even pressure with the squeegee at a consistent angle to push the ink through the screen onto the fabric. Typically, one or two passes are sufficient.
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Multiple Colors: When printing multiple colors, allow each layer to partially dry before applying the next to prevent bleeding. Flashing (briefly heating) between layers can help.
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Hydration is Key: Water-based inks dry quickly. If the ink starts to thicken on the screen, lightly mist it with water using a spray bottle to rehydrate it. This prevents clogging.
3. Post-Processing
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Curing: Water-based inks must be properly cured to ensure washability and durability.
- Heat Press: Cure at the recommended temperature (usually around 320°F/160°C) for the recommended time (typically 60-90 seconds).
- Conveyor Dryer: Pass the printed fabric through a conveyor dryer at the recommended temperature and speed. The ink needs to reach its curing temperature throughout the entire layer.
- Flash Dryer: Can be used but requires careful monitoring to ensure even curing without scorching.
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Washing: After curing, wash the garment inside out in cold water to remove any remaining residue and test the durability of the print.
4. Special Considerations
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Underbase: For printing on dark fabrics, consider using a white underbase layer of water-based ink. This provides a bright surface for subsequent colors. Alternatively, use "supercover" inks specifically formulated for dark fabrics.
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Cleanup: Clean screens and equipment immediately after use with water and a mild detergent designed for screen printing. Dried water-based ink is much harder to remove.
By following these steps, you can effectively use water-based inks to create vibrant, durable prints on a variety of fabrics.
