I have been mulling over a project like this for months, with all of the age/number t-shirts I've seen in recent catalogs. I think it's a fun idea for the kids, and I think it's a really great birthday gift! Then I remembered this project I found while surfing almost a year ago, and decided it could be adapted. All you need is a t-shirt, stencil, bleach, and a few minutes.
This time of year is what I call birthday season, since my girls and lots of their friends celebrate birthdays at the same time. So, I'm making quite a few of these right now!
I found some great t-shirts for $3 each (Wal-Mart!), in several bright colors. For the number, I just used Microsoft Word, a fun, thick font, and printed it to fit the entire sheet of paper. (I printed on white cardstock to make it a little heavier.) After printing, I cut out the numbers, and just set them right where I wanted them. (The link above suggested a spray adhesive, but I didn't use one.) To spray the bleach, I just put the shirt in the bathtub, positioned the numbers, and sprayed slowly.
I do recommend doing exactly as the tutorial says: spray up and let the bleach fall down on the shirt, instead of pointing directly at the shirt. The first shirt I did was heavily bleached, and the second was lighter. They both looked cute.
I also recommend opening the bathroom window for this project!
My crafty 15-year-old took one look at this and I could see the wheels spinning in her brain! She suggested a simple tie-dye could be done with this method. My soon-to-be 11 year-old is anxiously waiting to see if she gets a shirt like this for her birthday!
And finally, as I was browsing Pinterest last night, I saw this done with a bleach pen! Same concept, new idea!
So, don't pay $35 for a number t-shirt, when you can possibly make one for less than $5!