If the patch has sentimental meaning for you, you should sew it on. Keep in mind that sewing leaves permanent holes in your leather biker vest or jacket.Decide where you want your patch to go. At this point, I recommend laying the garment as flat as possible and attaching it with 3M adhesive spray. Put on the garment, get a photo taken, and then determine if that’s where you want it! If you decide to relocate it… Both glue marks can be removed with Goo Gone. Do you want to learn more? see here
Make sure there are no creases under the patch and that the garment is as smooth as possible. As you sew, the adhesive spray should hold the patch in place.Decide if you’ll stitch through the lining as well as the leather, or just the leather. To deal with leather only, carefully cut the lining’s bottom stitching and then re-sew. If you go through them, make sure the lining doesn’t pucker or distort the fit of the vest or jacket. A word of caution: When stitching patches on sleeves, this is particularly necessary. Extra material has been added to the lining to allow for elbow bending. The length of the sleeve will adjust if it is pulled up too far.
You must use nylon or polyester thread that is 100 percent nylon or polyester. The tanned leather will not respond with this form of thread (cotton thread tends to rot). For the best needle (for machine or hand sewing) for this project, call or go to your nearest fabric store. If you’re going to use a sewing machine, make sure it will go through all of the fabrics without damaging the needle.
If you’re hand-stitching, use a loop stitch that follows the patch’s edge. Start from the back and knot the end. Using a slip knot on the front and again on the underside once you’ve followed the edge all the way around.