These are fun and surprisingly sturdy. I made some for Christmas last year for each of my family and I am pretty sure they loved them. The trick to getting nice, thick coasters is using thick fabric, like upholstery fabric and a thick double-sides fusing like this awesome product, Bosal Craf-Tex. This particular product actually makes coaster sized, pre-cut, packages, but the store I was at only had the placemat packages, which actually turned out to be far more economical. This product is washable and very malleable. These are the materials I used, plus an iron, which I forgot to include and the sewing machine, which was in the other room.
Also, I didn’t mention needle and thread or glue to finish gap.
Here is my tutorial.
1) Decide how many coasters you want to make. Multiply this number by two and cut out that number of fabric squares. I have a square tool that I purchased a while ago that is 4 1/2″. This tool also makes it easy to draw where I want to sew, leaving a 1/2″ seam. My fusible interfacing should be the same size as my inner square. Cut out one fusible interfacing for each coaster. The fusible interfacing ends up being around 3 1/2″, though you may need to trim it up later. You really don’t need fancy tools. I bought that plastic square thing because I was making A LOT of these for Christmas. If you don’t have one or want one, the solution is simple: make a square template of 4-5 inches from cardboard. then, using 1/2 inch seams as a default, make another square template one inch smaller around than your first template.
3) Sew around three edges completely.
4) on the fourth edge, sew from the outer edge in on both sides leaving about a one inch gap. Remember to double back on edges and on each side on the gap so that the fabric doesn’t come apart as you turn over or stuff with your fusible interface.
5) Trim edges, EXCEPT the edge with the gap. Leave that untrimmed to make stitching it up a little easier.
6) Turn coaster pretty side out and use some thing fine-tipped (but not too sharp) to poke out nice crisp corners. Turning the coasters right-side out is actually the most frustrating part of this project. Sometimes the gap I have left is just big enough for my finger, but I have worked the most stubborn fabrics through impossible small openings. Be patient and don’t ruin all your hard work by tearing it apart.
7) Once you are satisfied that your corners are poked out, you are ready to stuff. Now … you are probably wondering how to get your three inch+ square into a one inch gap. Just roll up the fusible interfacing and stick it in. Manipulate it to lay flat inside.
8) Once in position, with everything tucked inside, get your iron out and set to medium. Fold in the edges in the gap so that they sandwich the fusible interfacing, that way you get a crisp edge. I ironed directly on the outer fabric for several seconds on each side.
9) Almost done! Stitch up the gap. Use your favorite stitch, or even glue and clamp together.