I use appliqué on many of my costumes, usually for trims but sometimes a cosplay calls for more than that.
Finding the right fabrics are half the battle; generally I try to find a thicker or heavier fabric if I know I will need to appliqué on it. If that is not an option I interface the back of the area I will be appliqué-ing so I get the thickness needed. Using a thinner fabric to appliqué on will distort the fabric once the stitching is finished (I always secure the appliqué with a zigzag stitch).
Depending on the project, I’ve used non-stretch to 4-way stretch fabrics to appliqué onto the thicker fabric. Though sometimes I’ve needed to use a thinner interfacing for the appliqué fabric so that it keeps it’s shape after a zigzag stitch; again, to keep it from warping.
If the appliqué is a trim, usually I can just measure out how long and wide it needs to be, but if the design is more complex I always make a to-scale paper mock up. Once I know what I need to cut out I iron Pellon’s 805 Wonder Under (can be bought at Joann’s or Amazon) onto the back side of the fabric I want to appliqué onto the base fabric. Since the Wonder Under has a paper backing (which will be the fabric’s backing until peeled off) I trace the paper mock up onto it. Once it looks how I need it to look I cut it out and then peel off the paper backing.
Carefully I arrange the newly cut appliqué onto the fabric I want it ironed onto and experiment with my iron’s heat settings using scraps of the fabrics I want to use. Some fabrics melt and others don’t take well to direct contact with an iron. If I am using a more difficult fabric I use a cotton scrap as a buffer and place over where I want to iron. Once I’m sure my fabrics will be safe, I iron the two together. I usually go over some spots a few times to make sure they are all fused properly.
Once everything is ironed together I match proper colored threads and zigzag stitch around the entire section of the appliqué. The only times I use a straight stitch is when the edges of the appliqué are not raw (aka cut). So if I’m appliqué-ing a ribbon on, the edges are already nice and finished so a straight stitch is all I need to secure it.
Firstly, since the trim material was a 4-way stretch I could get away with cutting straight pieces (and not on a curve to follow the lapel’s actual shape). After doing the math and deciding how wide I wanted to the gold trim to be AFTER sewing it all together, I doubled that measurement so I could stitch in the middle and fold it over the straight stitch. As you can see in the first image, the gold is sewn on with the back side facing up. After sewn on, I cut the excess gold trim on the section closest to the edge of the blue fabric, just so it’s one less piece to sew through (can get pretty thick).
I had already ironed on the double sided interfacing and once the gold was sewn and trimmed (only the one part already mentioned, I iron the gold towards the edge, smoothing out any bumps. After it was ironed in place (sticking due to the interfacing), I straight stitched the gold down.
The top portion of the trim was done separately and then straight stitched onto the lapel. After which the front and back sides of the lapel were sewn together.