Patching and Plastering - Plaster repair question

Can you use drywall mud to repair a crack or hole in plaster?

Yes, use a setting type drywall compound, it comes in bags and you mix it with water. It comes in variable set up times (from 5 min. to 45 min.). You need to work fast as it will harden in your pan. Mix only what you can use in say a 10 min. timeframe. Regular joint compound will shrink and crack if applied too thick. Setting type can be put on relatively thick without problems. Tape and sand same you would normal compound. If you need to add a textured look to match your plaster wall, time your swirls and scratches to the setting time of the compound. Blend with a moist sponge (not wet) and feather as needed. It usually takes several coats and a lot of fiddling to match an old texture pattern.

If you are fixing a larger hole, you will need to get some sort of backer board in behind the hole to give the patch some strength.

I also prefer to use a setting compound but regular joint compound will work. If the plaster is dusty you need to prime it prior to repairing. I like to scratch out the crack which allows the mud to have more points of contact = better repair :D

You can add to setting compounds to vary the setting time.

Citric acid, lemon juices, or full cream milk, will delay the setting time of a setting plaster.

Salt will speed up the setting time.

You can mix up a batch of plaster, take out enough to fill the hole, mix it with salt and it will set very quickly, while that in the bucket stays wet ready for the next coat.

A complete repair can be done with one mix this way giving it up to 4 coats.

Cheers


Rod Dyson