Painting Hair Cracks in Interior Plaster

Clean the crack and the surrounding area with an all-purpose cleaner. Rinse with a clean, damp cloth. Let the area dry completely.

Mix your plaster patch with water according to directions, if you purchased dry type. The consistency should be a little thinner than peanut butter. You will not need much; mix about a half cup of patching product.

Scoop some patch onto your putty knife. Apply it to the crack as if you were buttering toast. Apply it firmly so the material is worked into the crack. Don't spread it too thickly or too thinly. You should not be able to see the crack after you apply the patch mixture, but the area shouldn't be visibly raised.

Let the plaster patch dry completely, according to manufacturer's directions. Lightly sand the crack and surrounding area with the medium-grit sandpaper, wipe with a barely damp cloth to remove dust. Sand again with fine-grit sandpaper until the patched area is smooth and flush with the surrounding area, then wipe the area clean with a damp cloth, rinsing often, until all of the sanding dust is gone. Let it dry completely.

Paint the repaired area. If you have matching paint left over from painting the wall originally, use it to paint over the patched. Use a small paint roller to ensure even texture. Choose your paint roller based on the texture of the wall; the label will clearly state whether the roller is for smooth surfaces or textured surfaces. Let the first coat of paint dry thoroughly, then apply a second coat.

Take a trip to your local home improvement store and choose a variety of paint chips that appear close to the existing color of your wall if you don't have matching paint left over and do not want to repaint the whole wall. Compare the chips to the wall and choose the one that best matches.

Return to the home improvement store and purchase a small sample of the selected paint color and paint a small square on the wall to ensure the paint matches once dry.

Continue this routine until you find the right paint. Apply the paint to the wall as in Step 5.