Hardeners are the catalyst component in two-part adhesive systems — they initiate the chemical reaction that cures the adhesive from liquid to solid. The mix ratio of hardener to base adhesive controls cure time, final bond strength, and flexibility of the cured adhesive. Getting the ratio right is critical to a reliable bond. 

Pro Tool Haus carries replacement hardeners for common stone fabrication adhesive systems, including polyester hardener (MEKP), epoxy hardeners in standard mix ratios, and hardener systems for specific branded adhesive products. Always match hardener to its specific adhesive base — cross-using hardeners from different product lines produces unpredictable and potentially dangerous results. 

For complete adhesive systems see Adhesives. For color-matched adhesive work see Color Match and Color Pigment.