Leave a weight on top of the bristle side of the hairbrush to allow a good seal while the glue dries. Ensure the weight is light enough that it does not bend the bristles out of shape.

Leave the weight on as long as it takes for the glue to dry.

Allow the glue to dry completely before using your brush again. Drying times can vary between glue products. While hot glue dries relatively quickly, it can still take 24-48 hours to fully cure.