What am I doing wrong?

My shirts will literally NOT BLEACH. Here's a step-by-step, perhaps someone can tell me where I went wrong:

• Bought 4-pack of cotton Hanes shirts and freezer paper
• Printed out, traced, and cut out a design on the freezer paper
• Ironed it on, plastic side down
• Got bleach from under the sink, diluted it 50/50 with spray bottle
• On gray shirt, sprayed and dabbed, sprayed and dabbed
• Color's not changing, but shirt is soaked in bleach
• Try different bleach from the laundry room, it says it whitens clothes (so I figure it's gotta work), don't dilute it
• Try spraying more, nothing happens, even though shirt is soaked in bleach and I left it for over twenty minutes. The cardboard in between the shirt front and back, however, is very bleached

So then I read somewhere that new shirts sometimes have coatings and need to be washed. Fair enough. I throw 'em in on hot and dry them on hot. Attempt #2!

• Make stencil, iron it on, etc.
• Use the same undiluted bleach from before on gray shirt
• Shirt is soaked, but it's been 30 minutes and it's the same color, but the cardboard below is bleached like crazy
• Wash and dry it to be sure...yep, same color

What on earth am I doing wrong? I really, really want to make a bleach shirt but this is ridiculous!

edited to add a detail.