1. The heat of the burn will distort and pucker the leather immediately surrounding the hole. This damaged leather has to be cut away, enlarging the wound to release the torque lines caused by the heat. And, the leather in the surrounding area is prepared, typically with alcohol to remove any inhibitors to quality adhesion of the color coat.
2. A "plug" of leather is cut to the shape of the enlarged hole.
3. Sub-patch material is affixed with the sub-patch adhesive to the back side of the leather under the hole to give the repaired area some strength.
4. The leather plug is glued in place using non-flammable contact cement filling most of the hole.
5. The gap between the plug and the original leather is filled with a leather fill compound.
6. Once the fill is cured, a coat of color is then added with a hand held air brush. Getting the color to match is key to disguising the repair.
7. A grain pattern is then created on the leather to resemble the grain of the surrounding leather.
8. The color coat is re-applied. Steps 7 and 8 may be repeated multiple times as the area may be sanded gently, re-grained and recolored .
9. A top coat is then applied that covers the color coat. the top coat is a clear coat that protects the leather.
When done correctly, the end result looks like this.