None of the above made the point of getting all (and I do mean ALL) of the oil or fuel residue cleaned off around the area to be patched. Scrub thouroughly with denatured alchohol or thinner. It will also help to paint the surrounding area with SticsIt or a similar bonding agent. You can also use an alphatic resin glue to coat the surrounding (outside area of the patch) area. Use a very thin coat and let it dry befor ironing on the patch.