Filling cracks in plaster walls is a common maintenance task to keep the walls looking smooth and prevent further damage. Here's a guide on using crack filler for plaster walls:

1. Materials and Tools:

• Crack Filler: Choose a high-quality, paintable crack filler specifically designed for plaster walls. Some options include acrylic-based or elastomeric crack fillers.
• Putty Knife or Spatula: Use a putty knife or spatula for applying the crack filler.
• Sandpaper: Fine-grit sandpaper will be needed for smoothing the filled area.
• Primer and Paint: If you're planning to paint over the repaired area, have matching primer and paint on hand.

2. Preparation:

• Clean the Crack: Remove any loose debris, dust, or old paint from the crack using a brush or vacuum.
• Enlarge the Crack (if necessary): For better adhesion, consider using a putty knife to slightly widen the crack, creating a V-shaped groove.

3. Application of Crack Filler:

• Prepare the Filler: If the crack filler comes in a tube, cut the nozzle at a 45-degree angle to the desired width.
• Apply the Filler: Use the putty knife or spatula to fill the crack with the plaster filler, ensuring it's slightly overfilled.
• Smooth the Surface: While the filler is still wet, use the putty knife to smooth the surface, blending it with the surrounding plaster.

4. Allow for Drying:

• Follow Manufacturer's Instructions: Allow the crack filler to dry according to the manufacturer's instructions. Drying times can vary based on the product and environmental conditions.
• Avoid Disturbance: Do not touch or disturb the filled crack until it's fully cured.

5. Sand and Paint:

• Sand the Surface: Once the filler is completely dry, use fine-grit sandpaper to smooth the filled area until it's flush with the surrounding plaster.
• Prime (if necessary): If you've exposed new plaster, consider applying a primer before painting to ensure even color.
• Paint: Paint over the repaired area with a matching paint color. Make sure the paint is compatible with the crack filler.

6. Regular Inspection:

• Monitor for New Cracks: Periodically inspect the plaster walls for new cracks. Address them promptly to prevent further issues.

Tips:

• Multiple Layers: For deep or wide cracks, you may need to apply the crack filler in multiple layers, allowing each layer to dry before applying the next.
• Flexible Fillers: Consider using elastomeric or flexible crack fillers for areas prone to slight movement to prevent future cracking.
• Clean Tools Immediately: Clean your tools promptly after using the crack filler to ensure they can be reused.

Always follow the specific instructions provided by the crack filler manufacturer for the best results. If you're dealing with extensive plaster damage or structural issues, consider consulting with a professional for a thorough assessment.