How to Install Plastic Snaps: common mistakes and how to fix them

A lot of the patterns here at Goober Pea Designs use snaps - such as:

Because of this, we often have questions about using snaps. Either from those who have never used them before, or those who are just starting out and are having troubles with them coming apart. So here is a post to help with snaps!

First of all, what snaps and tools do we recommend?

We recommend Kamsnaps plastic snaps, in size 20 for most projects. Size 16 are easier to open and would be recommended for things like onesies. But for the projects I've listed above, size 20 is best.  The hand press is the most affordable tool to get started with, but also the trickiest to master - however, the tips below will help you use it like a pro, with no more snaps coming apart!

Note: if you do not have much strength in your hands/wrists, I would recommend the table press instead - it is pricey but easier to use, and requires a lot less strength.

The NUMBER ONE most common mistake I have come across, is pressing too slowly.

It is so easy to get focused on pressing HARD, that you don't realize you are pressing HARD AND SLOW. To press the centers of your snaps enough for them to stay together, you must press HARD AND FAST, in one swift motion. It helps to brace the bottom of your pliers on a flat surface.

The first picture below shows two snaps, the left one was pressed slowly, and the right one was pressed fast. You can see the the right center is smushed much more, and the plastic has spread wider and will keep that snap together. The left one will likely come apart with use, as you can see in the second picture below.

Another common mistake is pressing slightly off-kilter (not keeping the press straight while pressing).

This results in the center being smushed to one side, as shown below (in the left snap). This snap is also likely to come apart.

If you are pressing HARD, FAST, AND STRAIGHT, and your snaps are still coming apart, it may be due to the thickness of your fabric.

  • If your fabric is too thin, use nail clippers to snip the top of the post (the pointy part of the cap) so the middle can smush down closer to your fabric.
  • If your fabric is too thick, you may need LONG PRONG snaps. The below example is a snap that came apart because the fabric is too thick (fleecey sweater knit and minky). Note: I have had success using regular snaps on thick materials with the TABLE PRESS, but the hand press is difficult to get a successful press without long prongs.

The above solutions should fix any situation where snaps are coming apart with use. However there is one more common issue I would like to mention.

With certain fabrics, sometimes the snaps will actually rip right through the fabric and come out, though the snap itself is still together.

This generally happens with thin fabrics that fray easily, and/or stretchy fabrics.

Here are some tips to avoid this:

  • Use a medium/heavy woven (not stretchy) interfacing behind your snap, on the wrong side of the fabric.
  • Put FRAY CHECK/FRAY STOP/ETC on your hole before installing the snap.
  • With very delicate fabrics, I recommend using size 16 snaps, which will wear less at the fabric since they require less pressure to open.

I hope you find these tips helpful - I love working with my snaps on all kinds of projects! Kamsnaps can be purchased from their website directly ( or one of the many retail stores that stock them. In Canada, I recommend Black Rabbit Fabric.