Patchwork Coaster Sewing Tutorial

Patchwork coasters are a fun sewing project you can make in afternoon. Since they use small pieces of fabric, they’re great for using up scraps. You probably already have everything you need to make them!

I’ve got a tutorial for you below.

One thing I love about making patchwork coasters is they give me the opportunity to play with quilting without taking on a large scale project, like making an actual quilt would be. Each coaster takes just 4 half square triangles. That’s small enough you can just play around with color and pattern for the fun of it.

And when you’re done, you’ve got a pretty coaster that you can use with your morning coffee or afternoon snack. These coasters also make great gifts!!

I had everything I needed to make this set of 4 coasters already in my sewing room. I used some charm squares left over from a previous project to make the patchwork. I used a larger scrap to cut all of the backing pieces. I even used scraps of batting and cut up an old towel for the interlining.

You can use either batting or an old towel – or do like I did, and use both. The cotton batting is a smoother surface, while an old towel is more absorbent. I actually ended up using one layer of each because I wanted the absorbency of the towel but didn’t want the blue color of the towel showing through the light fabrics in my patchwork. An extra layer of cotton batting solved that and also created a more substantial coaster in the process.

Finished dimensions are approximately 4.5” square.

How to Sew Patchwork Coasters

The fabric requirements below are to make a single coaster. If you want to make a set of 4 coasters, just multiply the fabric requirements by 4. If you use different prints for all of your patchwork fabric, you can mix and match your half square triangles to create a scrappier look for your coasters.

For a single coaster:

2 4” squares of quilting cotton

1 4.5” square of cotton batting or an old towel

1 6” square quilting cotton for the backing/binding

Fabric starch

Glue stick

All seam allowances ¼” unless otherwise noted. RST = right sides together.

Sew the Half Square Triangles

Accuracy is important when sewing half square triangles. If your seams are a little wonky or your seam allowance slightly off, you’ll end up wonky half square triangles.

Place 2 4” squares of fabric RST.

Sew around all 4 sides. Do NOT leave a hole to turn right side out.

Use an erasable fabric marking pen to mark diagonal lines from corner to corner.

Cut the piece along these lines to create 4 half square triangles.

Press the seams open, being careful not to stretch the fabrics.

Because of how these squares of fabric are sewn together, the outside edges are actually cut on the bias. This means that it’s super easy to stretch these squares out of shape.

Starch each of the half square triangles. This will help keep them from stretching and warping as you handle them.

Sew the Patchwork Design

Now for the fun part – assembling your half square triangles into a patchwork design!

Arrange 4 half square triangles into a pleasing pattern. I arranged mine so they created a pinwheel effect.

You could also arrange them so they create a diamond.

Or a checkerboard diamond.

When you’ve got a design that you like, sew the pieces together being careful to match corners.

First sew the two pieces in the top row together RST. Press seam allowance open.
Then sew the two pieces in the bottom row together RST. Press seam allowance open.
Finally, sew the top row to the bottom row RST. Press seam allowance open to create a 2×2 block.

Quilt the Patchwork Block

Layer the patchwork block on top of your batting and/or towel square.

I used both batting and an old towel to give more structure and absorbency to my coaster, but that’ totally optional. One layer will do just nicely if you want to keep things simple.

Glue baste in place to keep the layers from shifting. Go over the area with a hot iron to make sure the glue is good and dry before sewing.

Stitch some simple quilting lines across your patchwork piece. I just stitched in the ditch along all of the seams.