Embroidered Iron On or Sew On Patch The patch is approx. 1in tall. Length is determined by number of letters. Max. 14 letters incl. spaces. How to iron on patches: Fabrics like denim and cotton provide the best base for iron-on patches. Be careful with polyester or delicate fabrics, since applying the high heat necessary for ironing on patches can burn the fabric or cause it to get discolored. You need a stable and hard surface to iron on, since you have to apply high pressure to the patch. To iron on the patch turn your iron to cotton setting and turn off the steam function. I recommend you to place a peace of backing paper or a thin towel over the patch and fabric. Place the iron for 15-20 seconds with pressure on the patch, don't move the iron around! The iron is big enough to cover the whole patch. The glue needs to bond with the fabric so it is important that you have no movement. After 20 seconds lift the iron and wait another 5-10 seconds before you move item. At this point the patch should already stick to the fabric. Repeat the process from inside out. Important: Don't move the iron or fabric during the process. If you frequently wash or wash & dry the item, I recommend you to secure the patch with a couple of stitches around the border.