Drywall Mudding Habits That Keep the Coats Smooth

The Problem

First-time drywall finishers tend to fight the mud: it drags, it ridges, it squeezes off the edges of the knife, and every coat ends with a long sanding session that fills the room with dust. Most of that fight comes from a handful of working habits, not from lack of skill.

The Techniques

Knock down high spots instead of sanding between coats

Don't sand between coats. Run your knife over the dried coat and scrape down the ridges and high spots. The next coat covers what's left.

Thin the mud with water

Factory consistency is too thick to flow smooth off the knife. Add a little water and mix before you start scooping.

Don't overload the knife

Take a modest scoop and knock the corners off it against the pan or bucket edge. A squared-off blob of mud squeezes out past the edges of the blade as you draw it.

Keep every coat thin

You're building up the taper between boards over several coats, not filling it in one pass. A thin coat also dries in time to get another coat on the same day. Inside corners take the longest to dry, so go thinnest of all there.

Use the knife's flex to find your edges

The blade flexes. On a butt joint, lay on an even coat, then flex the knife and scrape off along one edge — now you can see exactly where the buildup ends. Do the top edge, then the bottom, then fill between them.

Keep the lid on the bucket

Open mud dries out, and debris falls in. Both end up as drag marks in your next coat.

Keep the knife clean

Keep a bucket of water nearby and rinse the blade as you work. Mud that dries and crusts on the knife drags lines through every pass after that.

Don't chase flaws in a wet coat

A clump or trash spot in a fresh streak isn't a problem. Drag it out flat and let the next coat bury it. Each coat only needs to be even, not pretty — the last one is the one that counts.

Safety note: A metal taping knife bridging the two terminals of a live switch or outlet will short with a pop. Kill the breaker before coating around electrical boxes with uncovered devices.