Lift up both edges of the rip gently with a pair of tweezers to examine the leather. Cut off the frayed or jagged edges with a scalpel or X-Acto knife to create a flat and clean edge on both sides of the rip.
Moisten a clean cloth with rubbing alcohol and wipe around the rip in the arm of the leather sofa. The alcohol will remove any dirt or oily residue on the leather material. Dry the area for two to three minutes with a hair dryer.
Measure the length of the rip in the arm of the sofa with a tape measure. Add two inches to the total measured length.
Cut a piece of canvas sub-patch. It should extend one inch past each end of the rip and be at least three inches wide.
Grasp the canvas sub-patch with tweezers and insert it into the rip so it lays flat underneath. Use the tweezers to lift the edges of the rip and squeeze a thin layer of leather glue on the underside of both edges between the arm rip and canvas sub-patch.
Press the edges down onto the canvas sub-patch so they lay flat. Hold the edges down firmly for up to five minutes.
Squeeze a tiny amount of leather filler inside the leather rip on the arm of the sofa to create a very thin layer. Smooth the leather filler flat with a palette knife. Dry the filler with a hair dryer for two to five minutes.
Apply another thin layer of leather filler into the rip and dry with the hair dryer. Continue to insert leather filler into the rip until the area is almost full.
Fill the rip with the last layer of leather filler and smooth it even with the palette knife. Lightly press a grain pad onto the wet leather filler to replicate the texture the leather sofa may have. Allow the leather filler to dry for at least 30 minutes.
Apply the leather colorant over the dried filler with a sponge. Refer to the color guide and application directions included in the leather repair kit for complete instructions. Allow the leather colorant to dry for at least four hours before applying additional coats of color.
Apply additional coats of leather colorant, using the sponge, if desired.
Squeeze a small dot of leather protector and conditioner onto a clean cloth and apply it to the repaired area.