How do you use a mortar chisel?

A mortar chisel is primarily used for the precise and efficient removal of old, deteriorated mortar from the joints between bricks, blocks, or stones, preparing them for new mortar application in a process known as repointing.

Understanding Mortar Chisels

Mortar chisels are specialized tools designed to fit into narrow mortar joints. They can be used manually with a hammer or mallet, or as attachments for power tools like rotary hammers, which provide percussive force for quicker removal. Their precision is crucial to avoid damaging the surrounding masonry units.

Key Steps for Using a Mortar Chisel

Effective use of a mortar chisel involves a combination of technique, careful control, and adherence to safety. Here’s a detailed breakdown:

1. Safety First:

   • Always wear appropriate Personal Protective Equipment (PPE), including safety glasses (essential to protect against flying debris), work gloves, and a dust mask.
   • Clear the work area of any obstructions.

2. Chisel Selection:

   • Choose a mortar chisel with a blade width that is equal to or slightly narrower than the mortar joint you are working on. This ensures maximum efficiency and minimizes the risk of damaging the brick face.
   • If using a power tool attachment (e.g., with a rotary hammer, as referenced in the video title), ensure the chisel is compatible with your tool.

3. Positioning and Scoring the Joint:

   • Position the chisel's cutting edge precisely along the mortar joint.
   • Crucially, as highlighted in the reference, you must "gently score along your cut line you don't want to damage the brick." This initial light scoring creates a guide and helps prevent the chisel from slipping and marring the bricks.
   • This gentle scoring technique is vital for both horizontal and, as specifically mentioned, when you "score vertical joints."

4. Applying Force for Mortar Removal:

   • Manual Use: If using a hand chisel, strike the head of the chisel firmly but controllably with a brick hammer or mallet. Adjust the force based on the mortar's hardness.
   • Power Tool Use: When using a mortar chisel attachment with a rotary hammer, let the tool's percussive action do the work. Guide the chisel steadily along the joint, maintaining consistent pressure and angle.

5. Working in Corner Spaces:

   • The reference specifically advises learning "how to work in corner spaces." These areas require extra care and often a different angle of approach. Angle your chisel to get into the corner without hitting the adjacent masonry units. You might need to use a narrower chisel for these tight spots.

6. Progressive Removal:

   • Work systematically along the joint, removing mortar in small, manageable sections. Avoid trying to pry out large chunks, as this can put undue stress on the bricks and cause damage.
   • Angle the chisel slightly downwards to prevent it from wedging under the brick and prying it loose.

7. Damage Prevention and Adjustment:

   • Continuously monitor your work. The reference provides a critical warning: "If you do find your damaging" the brick, stop immediately. Reassess your technique. This might mean:
     • Reducing the force applied.
     • Adjusting the angle of the chisel.
     • Using a different size or type of chisel.
     • Taking smaller, more controlled passes.

8. Cleaning the Joint:

   • Once the mortar is removed to the desired depth (typically about 1/2 to 3/4 inch for repointing), use a whisk brush or a shop vacuum to remove all loose debris and dust from the joint. This ensures proper adhesion for the new mortar.

Tips for Successful Mortar Chisel Use

By following these guidelines and paying close attention to the delicate balance between effective mortar removal and brick preservation, you can successfully use a mortar chisel for your masonry projects.