A finish that protects surfaces from moisture and debris, polyurethane also seals surfaces that contain scratches and other imperfections. The material is similar to paint and available from a variety of manufacturers. Polyurethane is easily applied with a paint brush or roller and dries quickly. Applying the material with a roller eliminates brush strokes and lines and prevents over-applying the material. Polyurethane is available at hardware, home improvement and paint supply stores as well as online.

...
Yes, you can use a paint roller to apply polyurethane.

Applying Polyurethane

Step 1

Pour 2 cups of mineral spirits in a paint pan. Wear latex gloves and a nose mask to keep the chemical off of your hands and out of your lungs. Pour the polyurethane in another paint pan. Arrange the pans next to each other near the surface or area you want to coat with polyurethane.

Step 2

Place the roller in the pan of mineral spirits and dampen the roller's surface completely. Shake off any excess. The roller should be damp — not dripping in mineral spirits. The mineral spirits aids in applying the polyurethane.

Step 3

Place the paint roller immediately in the pan of polyurethane and dampen the roller's surface completely.

Step 4

Roll the polyurethane on the surface or area you want to cover. Roll on the material quickly and cover the surface or area until the roller no longer contains any polyurethane.

Step 5

Repeat steps 2 through 4 if you need to reapply polyurethane to the roller to finish applying the first coat. Let the polyurethane dry according to the recommended time on the material's container.

Step 6

Sand the surface or area you are applying polyurethane to with a piece of 280- or higher grit (fine) sandpaper to roughen up the polyurethane for accepting a second or additional coat of the material. Dampen a soft cloth or rag with mineral spirits, wring out excess and wipe the surface or area to remove any loose sand dust.

Step 7

Place the paint roller in the pan of mineral spirits and dampen the roller's surface completely after applying the first coat. Shake off any excess. Place the roller in a freezer bag and let the pan air dry.

Step 8

Repeat steps 2 through 7 to apply additional coats of polyurethane to the surface or area you want to cover.

Clean Up

Step 1

Wash the paint roller under hot running water to remove any polyurethane and mineral spirits from the roller.

Step 2

Use a flathead screwdriver to pop out the dried matter from the pan containing mineral spirits. Wash the pan under hot running water or dispose of the pan in your home's outdoor trash can.

Step 3

Pour any excess polyurethane into a plastic or metal container and close its lid tightly. Dispose of the container in your home's outdoor trash can. Do not pour the excess polyurethane back into its original container — this will make the polyurethane in the original container too thin.

Step 4

Wash the pan that contained polyurethane under hot running water or dispose of the pan in your home's outdoor trash can.

Step 5

Dry the paint roller and pans, if you kept them, with a soft cloth or rag. Store the items in your garage or other space for reuse.