How to Customize Active Shirts with Screen Printing?

▸Why Customize Your Active Shirts?

Personalizing active shirts lets you stand out during workouts or team events, turning generic tees into branded gear that withstands sweat and washes. Many gym-goers and small teams struggle with low-quality iron-ons that crack or fade—screen printing delivers vibrant, long-lasting results on polyester blends.

In this guide, you'll learn the full process from design to curing, tailored for intermediate DIYers comfortable with basic crafting. Expect professional hand-feel on activewear with the right inks. The process takes 4-6 hours total, including drying, and assumes you have some art software experience.

We'll cover polyester-specific tips to avoid bleeding or cracking, so your shirts perform as good as they look.

▸What You'll Need

• •Blank active shirts (polyester or poly-blend, e.g., 50/50 cotton-poly for best ink adhesion)
• •Screen printing frame (110-156 mesh count for activewear; 20x24" size recommended)
• •Photo emulsion and sensitizer (or pre-coated screen)
• •Transparency film for film positive
• •Scoop coater
• •Exposure unit or bright halogen lamp/UV light (DIY option: sunny day)
• •Squeegee (medium hardness)
• •Low-bleed plastisol ink (white or colors suited for poly)
• •Pretreatment spray (optional but recommended for poly shirts)
• •Tape (blockout and packing)
• •Printing station or DIY setup (platen, hinge clamps)
• •Heat press or conveyor dryer for curing
• •Design software (e.g., Adobe Illustrator or free Inkscape)
• •Degreaser and washout sink/tub
• •Gloves, apron, and cleanup supplies

Estimated Time: 4-6 hours (including drying and curing; 2-3 hours hands-on) Difficulty: intermediate

▸Step-by-Step Instructions

Step 1: Design Your Artwork

Start by creating a vector-based design optimized for screen printing. Use software like Adobe Illustrator to make bold, simple graphics with at least 50-100pt fonts—no fine details under 1pt, as they won't resolve well on mesh screens.

Convert colors to spot colors (one per screen). For active shirts, design for 1-4 colors max to keep it intermediate. Output as 100% opaque black positives on transparency film at high resolution (300 DPI). Success: Crisp film positive that blocks light completely where ink should print.

💡 Tips:

• •Add 10% halftone dots for gradients on poly fabrics.
• •Test print on paper first.

⚠️ Warnings:

• •Avoid gradients or photos without separation; they'll blur.

Step 2: Prepare and Degrease the Screen

Select a 110-156 mesh screen for active shirts—higher for detail, lower for heavy ink deposit. Clean the frame thoroughly with degreaser and rinse. Dry completely. This removes oils for even emulsion adhesion.

Tape off edges to prevent leaks. Success: Screen feels squeaky clean and water beads off.

💡 Tips:

• •Use a lint-free cloth to avoid fibers.

⚠️ Warnings:

• •Skip degreasing and emulsion won't stick evenly.

Step 3: Coat the Screen with Emulsion

Mix emulsion with sensitizer per instructions (usually 10:1). Use scoop coater to apply thin, even layer on both sides (substrate side thicker). Dry in dark for 1-2 hours or use fan. Aim for 15-20 microns thick.

Success: Uniform green coating that doesn't drip or streak.

💡 Tips:

• •Coat in low light; emulsion exposes fast.

⚠️ Warnings:

• •Too thick = hard washout; too thin = pinholes.

Step 4: Expose the Screen

Place film positive ink-side down on emulsion-coated screen, taped secure. Expose under UV light (10-15 mins for 1000W halogen, follow kit chart). Success: Styrene smell indicates proper exposure; unexposed areas wash out easily.

For active shirts, precise exposure prevents ink bleed.

💡 Tips:

• •Use exposure calculator app for accuracy.

⚠️ Warnings:

• •Underexpose and design washes away; overexpose and it won't.

Step 5: Wash Out and Dry the Screen

Rinse with cool water pressure washer or hose until design opens clearly (5-10 mins). Block out pinholes with tape/emulsion. Dry screen 30-60 mins. Success: Sharp stencil with open image area.

💡 Tips:

• •Use power washer for faster cleanout.

⚠️ Warnings:

• •Hot water ruins emulsion.

Step 6: Prepare Shirt and Station

Pre-treat poly shirts with spray if needed for adhesion. Stretch shirt taut on platen. Register screen with tape marks for multi-color. Success: Shirt flat, no wrinkles.

💡 Tips:

• •Use adhesive spray on platen for grip.

⚠️ Warnings:

• •Wrinkles cause uneven prints.

Step 7: Print the Design

Flood ink across screen, then pull squeegee at 45° angle with firm pressure. Lift screen straight up. Off-contact 1/16". For poly, use low-bleed ink. Success: Smooth, opaque print without smudges.

💡 Tips:

• •Practice pulls on scrap fabric.

⚠️ Warnings:

• •Too much pressure bleeds ink on poly.

Step 8: Cure and Finish

Flash cure between colors (160°F 10 sec). Final cure at 320°F for 60-90 sec in heat press. Cool, inspect. Wash test: Survives cold wash/hot dry. Success: Flexible print that doesn't crack.

💡 Tips:

• •Double flash for thick ink.

⚠️ Warnings:

• •Undercure = washout fails.

▸Pro Tips

• •Use low-bleed white underbase on dark poly shirts for pop.
• •Register multi-color with micro registration on frame.
• •Test ink cure temp on fabric swatch first.
• •Print 10+ shirts at once for efficiency.
• •Store screens flat in dark to reuse.
• •Add softener to ink for better hand on activewear.
• •Sun exposure works for small runs—consistent 10 AM light.

▸Common Mistakes to Avoid

• •Using regular plastisol on 100% poly—causes cracking; switch to low-bleed or discharge.
• •Poor registration—prints misalign; always use registration marks.
• •Skipping pretreatment on blends—ink ghosts; spray evenly.
• •Over-inking—smeared prints; flood lightly.
• •Rushing cure—fades after first wash; hit 320°F fully.

▸Troubleshooting

Problem: Pinholes in stencil

Solution: Block with emulsion tape; recoat next time with even layer.

Problem: Ink bleeding on poly

Solution: Use low-bleed ink + pretreatment; reduce flood amount.

Problem: Fuzzy edges

Solution: Higher mesh screen + sharper film positive; check exposure.

Problem: Print cracks after wash

Solution: Undercured—increase heat/press time; use flex additive.

Speedball 2-Color Poly Screen Print Fabrics Kit

Complete kit with poly-friendly inks, screens, and tools—ideal for active shirts without buying extras.

Best for: Single to dual-color custom gym tees.

Price Range: $59.99

Ryonet Low Bleed Plastisol Ink Starter Set

Prevents cracking on polyester activewear for durable prints.

Best for: Multi-color designs on moisture-wicking shirts.

Price Range: $29.99-$49.99

Gildan DryBlend 50/50 T-Shirt (Active Blank)

Perfect poly-blend base—inks adhere well, holds shape through washes.

Best for: Budget blanks for teams or personal use.

Price Range: $8-$12 each

Cricut EasyPress 2 Heat Press

Even heat for perfect curing without scorching active fabrics.

Best for: Final step for soft, flexible prints.

Price Range: $149.99

Speedball Photo Emulsion Kit

Reliable for sharp stencils on repeated use.

Best for: Custom screens for frequent printing.

Price Range: $19.99