Should I Sand Between Coats Of Polyurethane?

When It Makes Sense

• Good fit: You are refinishing a hardwood floor, table, or cabinetry where a perfectly smooth, high‑gloss finish is expected, and you have the time and tools to sand lightly between each coat.
• Good fit: You are using an oil‑based polyurethane that tends to raise the wood grain or trap dust, and you want each subsequent layer to bond securely for maximum durability.

When You Should Avoid It

• Warning sign: The project is a low‑budget, quick‑turnaround job (e.g., a temporary shelf) where a slight imperfection is acceptable and the added labor isn’t justified.
• Warning sign: You are applying a modern water‑based polyurethane that self‑levels and dries clear; excessive sanding can actually create more visible scratches and require extra polishing.

Pros and Cons

Pros

• Improves adhesion between coats, reducing the risk of peeling or chipping over time.
• Creates a smoother surface by removing dust particles, bubbles, or raised grain, leading to a more professional finish.

Cons

• Adds extra time, effort, and material (grit, tack cloth) to the project.
• If over‑sanded or done with too coarse a grit, it can damage the wet or partially cured layer, necessitating additional coats to correct.

Decision Checklist

• Do I need a flawless, high‑durability finish for a high‑traffic or visible surface?
• Am I using an oil‑based polyurethane or a water‑based formula that benefits from mechanical adhesion?
• Do I have the proper sanding tools, grit progression, and a clean environment to avoid re‑contaminating the surface?

Alternatives to Consider

If sanding seems cumbersome, you can opt for a high‑quality water‑based polyurethane that self‑levels, apply a thin “wipe‑on” finishing coat between full coats, or use a sanding sealer as the first layer to smooth the wood before any polyurethane is applied. Each alternative reduces sanding steps while still delivering a decent finish.

Final Recommendation

For projects where appearance and longevity are paramount—such as fine furniture, flooring, or cabinetry—sand between coats of polyurethane, using 320‑ to 400‑grit sandpaper and a clean tack cloth. For quick, low‑budget, or water‑based applications, you can generally skip sanding and rely on the product’s self‑leveling properties. Always work in a well‑ventilated area, wear appropriate protection, and if you’re unsure about the technique, consult a finishing professional.