How should a painter apply the second coat of joint compound on new gypsum panels?

• A. Apply with a 300 mm (12 in.) knife, feathering beyond.
• B. Apply with a 200 mm (8 in.) knife, feathering slightly beyond the first coat.
• C. Apply with a 50 mm (2 in.) knife, feathering.
• D. Use a trowel for the second coat.

Answer: (B)

The technique being tested is choosing the right knife size and feathering approach for the second coat to build out the joint and start blending it with the first coat on gypsum panels. The second coat should be applied with a knife wide enough to cover the seam and begin a smooth transition, but not so wide that you lose control. An eight-inch knife hits that sweet spot: it provides enough width to fill and level the joint, while still allowing you to feather the edges gently beyond the first coat.

Feathering slightly beyond the edge of the first coat is important because it creates a gradual transition rather than a hard line. That subtle extension helps the final surface look even after sanding and priming.

Using a much larger knife, like a twelve-inch one, can remove too much of the first coat and make it harder to control the feather. A small two-inch knife would be too narrow to smooth the seam effectively. A trowel isn’t appropriate for drywall joint compound on gypsum panels, as it doesn’t give you the right balance of control and finishing quality for this step.

So, the eight-inch knife with slight feathering beyond the first coat is the best approach for the second coat.