HRM™ Historic Restoration Mortar from Bonstone is a two-component, lime-based, latex modified mortar for the restoration of historic masonry structures. Basic uses include surface repairs to historic stone and masonry structures and skim coating vertical stone. It is designed for durable aesthetic repairs, and formulated to be easy to mix and apply to the surface. It was also designed as a slurry or knife-grade application.
Limitations are use on oil, grease and coating free substrates, according to Bonstone.