Ever wonder how we fix hairline cracks in failing plaster? Here is the quick breakdown.First, we open the crack a bit so the repair material has something to grip. Where the crack ends, we score a short perpendicular line to help stop it from spreading any further. Then we vacuum it clean and seal the flaky edges with Peel Stop or an oil-based primer.Next, we pre-fill with joint compound, apply mesh tape for strength, and build it up with a few more layers of joint compound, going a little wider