How to Repair Mortar in a Brick Wall

Mist the brick again. Then, following the directions on the bag, stir water into the dry mix until it reaches the consistency of peanut butter and clings to an upended trowel. Wait until a film of water forms on the mix, about 15 minutes. Stir the water back in. The mortar is now ready to use and remains workable for 8 hours. If it gets too dry in that time, you can "retemper" it occasionally by adding water.