Setting-type joint compound is harder to apply smoothly and to sand, so it is not the best option for beginners. It is preferred by pros because it dries quickly.
Remove the dust from the crack by brushing it out with a paint brush or using a hand vacuum cleaner.
Drying can take from 20 minutes for each coat of setting-type joint compound to 24 hours for a thick first coat of pre-mixed compound. [4] X Research source If the cut is deeper than 1⁄4 inch (0. 64 cm), you may need to press a strip of mesh or paper tape into the first layer of compound before it dries to better seal the crack. [5] X Research source Thinner coats are ideal as they’re easier to sand down to match the wall once dry. [6] X Research source
80-grit (medium-grit) sandpaper can eliminate larger bumps whereas a finer 120-grit can be used for finishing touches. [7] X Research source One option is to sand in between coats to avoid having to sand as much at the end. [8] X Research source
The exception to this is if you used a paint and primer in one. Then you only need a coat or two of the paint directly on the affected area.
Sealing the patch with a heavy-duty water-based polyurethane with a brush can prevent stains and other marks. [13] X Research source
Dampening the crack before applying the compound will remove any loose particles and help the compound stick better.
For setting-type joint compound to dry thoroughly, the room should be between 55 and 70 °F (13 and 21 °C).
Use a feathering technique when applying the compound. With the knife at a 70-degree angle, start at the center and pull the knife to the outside edges of each coat, increasing pressure the further away from the middle you get. [19] X Research source
It’s smart to wait at least 24 hours prior to painting to ensure the compound is completely dry. . [20] X Research source
