How to Decorate Baby Onesies with Your Cap Press or Clam Shell Press

My favorite thing about spring? All the new life! It’s the season of newborns for plants and animals alike, so I thought it’s the perfect chance to share this “Just Hatched” cut file with all of you! It’s just in time for Easter, but could be used for a newborn any other day of the year. You can switch up the colors and type of heat transfer vinyl for the look you’re going for, but I’m using Lemon Sugar and Mermaid Blue Glitter HTV.

Step 1: Cut HTV

Glitter HTV is cut with the carrier side down. Sometimes HTV has a white back like Lemon Sugar. It’s typically seen on lighter colors, and is there to protect the integrity of the color and ensure it’s opacity. So even if I put this on a black onesie, the yellow color will look just as pretty as it did before it was applied!

Cutting Glitter heat transfer vinyl on Silhouette Cameo

When working with HTV, always mirror your cut file! Our suggested cut settings can be found on the Siser website.

Step 2: Weed HTV

After cutting, weed out the excess with a Siser® Weeder. This tool is sharp and efficient! Plus the grip is a savior during those long hours of weeding.

weeding Lemon Sugar Glitter heat transfer vinyl Weeding cavities from Mermaid Blue Glitter HTV








When all that remains on the clear carrier is the heat transfer vinyl you want to transfer on the onesie, then you can use this quick clean up trick- a lint roller grabs even the smallest of HTV scraps!

Quick clean up trick with a lint roller

Step 3: Heat Apply the HTV on the Onesie

A clean work area means you’re less likely to accidentally press an errant scrap. Speaking of pressing, did you know onesies can be pressed with a cap press or a clam shell press?

Apply HTV on onesies with a cap press or a clam shell press

The smaller platen of the cap press allows you to apply HTV without the use of a heat transfer pillow since all the seams and snaps naturally rest outside of the pressing area.

how to apply HTV on a onesie with a cap press

The onesie seams naturally rest off of the pressing platen.



When using a clam shell press, a heat transfer pillow is required to raise the application area above the bulky shoulder area and seams. Either way, we’re achieving a flat pressing surface in order to have even pressure during application. Without even pressure, areas of the HTV won’t stick to the fabric. Sometimes this is immediately noticeable, and other times you discover pressure problems after the wash!

Place a heat transfer pillow inside the onesie when using a clam press

A heat transfer pillow is required to raise the pressing area above the onesie seams.

The pressing process is the same although it appears differently! Glitter has best results when applied at 320°F for 10-15 seconds.

  • Press 1: Should always be a pre-press to remove any wrinkles or moisture in the fabric.

pre-press the blank onesie remove moisture and wrinkles


  • Press 2: In this case, layer 1 is Lemon Sugar Glitter with a heat transfer cover sheet on top. Since we’re layering two colors, I only pressed for 1-5 seconds before peeling the carrier hot.Peel the carrier hot from the first layer


  • Press 3: After aligning the Mermaid Blue text inside the cut outs, place a heat transfer cover sheet on top and press for 10 seconds. Then peel the carrier warm.

layer 2 is Mermaid Blue Gitter heat transfer vinyl Move the onesie off the heat press and peel the carrier warm









I followed the same 3 steps to decorate the white onesie, but instead of a cap press, the clam shell press and a heat transfer pillow were used. I got great results with both methods- Your choice depends on the equipment you have available and how you prefer to apply HTV!

Finished onesies for Easter or a newborn

Now it’s your turn to try! Download the Just Hatched cut files HERE and get crafting! Just remember, if you actually sell baby onesies, “onesie” is trademarked by gerber so you’ll need to call them “baby bodysuits” or something else creative.

If this post was useful to you, please pin the link below! You can see more Easter ideas on our Pinterest board: Easter HTV Ideas !

Decorate onesies with your Clam Shell Press or Cap Press. Get all of Siser's tips plus the FREE CUT FILE on the Siser Blog.