How to Tuckpoint Mortar Joints and Bricks
Carefully remove existing worn mortar to 15-20mm from the brick face usually with a grinder and dust vacuum, cleaning the joint out with compressed air and or water.
Colour match and mix replacement mortar injected directly into the joint thru a caulking gun. A proprietary acrylic chemical when added to water in the mix allows the mortar to flow without smearing the brick or stone face, ie no messy pushing off a trowel.
The mortar is tooled flat almost flush and not more than 1mm above the brick or stone face filling damaged and or irregular edges providing a flat surface as done by the original tuck pointer. Lightly draw the positions of the tuckpoint vertical and horizontal lines as they were originally placed, sometimes on the brick or stone face to retain the pattern.