When searching for tutorial inspiration for how to decorate onesies I found several that suggest using a pencil eraser dipped in fabric paint to make polka dots. While I like this creative solution, I took the idea a step further and figured out a way that I think is easier and produces cleaner results. All you need are scissors, cardboard (I used an old cereal box), and those sticker reinforcements used on hole punched paper that you can find at any office or school supply store (or aisle).
In addition, you’ll need fabric paint and either small paintbrushes, sponges, or foam brushes. I used thin paint brushes and it worked out fine.
I bought primary colors of fabric paint and then mixed them to make additional colors like orange and green.
Cut the cardboard to fit inside of the onesie, taking care to make it large enough to cover any area you want to paint. Don’t make it too large that it stretches out the fabric too much, though. Use binder clips or clothespins to secure the fabric to the cardboard so that nothing moves as you are painting. Place your stickers on the fabric. Be creative! I wanted an overall polka dot look but you can also make shapes, patterns, words, or initials.
Carefully paint over the stickers with the colors of your choosing. I decided on a rainbow color theme.
Paint inside of each circle and don’t worry if you paint on the sticker, too. Just don’t paint outside of the sticker by mistake unless you are trying to use the reinforcement to create negative space circles, which, of course would also be súper chévere!
I dried the paint with a hair dryer and then painted another coat on top of that. Two coats seemed good enough for this fabric and paint so after drying the paint again, I peeled off the stickers and you can see the result above.
Another way to decorate a onesie (or any piece of clothing) is by using a stencil with fabric paint or fabric markers. I created this sunglass stencil in Adobe Illustrator and then printed it. You can find any number of simple, silhouette designs online to use.
I traced the design onto a sheet of plastic with permanent marker and then cut it out with a utility knife. For the plastic, I used an old sleeve I found like those used to protect reports or papers. You can use transparency film or any heavy duty plastic you can find in school or office supplies. If you don’t want to reuse your stencil, butcher paper, thin cardboard, freezer paper, or just plain printer paper will suffice but it’s more difficult to get a clean edge and most likely they are single use only. Tape your stencil to the fabric with painter’s tape, washi tape, or electrical tape. These won’t damage or leave residue on your fabric.
Make sure you place the piece of cardboard inside and that it covers your design but doesn’t stretch out the cotton too much.
Again, use binder clips to secure your fabric to the cardboard so that nothing moves while you paint.
Paint the inside of your stencil, pushing down the edges of your design to touch the fabric as you go to ensure a clean edge.
I used the hair dryer again and took off the stencil. Here’s the result! When your fabric paint is completely dry (my bottle says to let it dry overnight) turn your onesie inside out and iron the opposite side of your design. While it might not be entirely necessary, I always did this with my silkscreen projects to set the paint and they didn’t fade after washing. Place a piece of scrap fabric between your ironing surface and your design just in case it bleeds.