How to Paint on Masonite

Masonite is a proprietary pressed-wood product, made by Masonite International Corp., that is made from wood chips that have been reconstituted under pressure with resin. It comes in exterior and interior grades and is commonly used as siding. Painting masonite requires a fair amount of preparatory work because the surface is porous.

Things You'll Need

• Oil-based primer
• Paint (semi-gloss enamel)
• 3-inch to 4-inch bristle brush
• 220 grit sandpaper
• Sanding block
• Track cloth

Instructions

1. Install the masonite before painting and then go over the surface, looking for holes and blemishes. Fill these in with wood filler and let dry.

2. Wrap sandpaper around sanding block and sand the masonite, leveling the spots you filled with wood filler and smoothing out the entire board. Exterior-grade masonite may come with a factory-applied primer coat, but that is intended to protect the boards during transit only. Exterior-grade masonite still needs to be sanded.

3. Wipe the boards clean with the tack cloth. You want to eliminate as much dust and wood residue as you can.

4. Apply the primer coat, using long strokes to prevent the paint from pooling. When finished, let dry.

5. Sand again and go over the masonite with the tack cloth, again to remove dust and wood particles.

6. Apply two coats of paint, letting the first coat dry thoroughly before applying the second one. Masonite is vulnerable to moisture damage and needs to be completely sealed with paint to keep moisture from being absorbed.

Tips & Warnings

• If you don't let the first coat of paint dry thoroughly before applying the second, the paint could prematurely peel from the primer.

References

• Masonite
• Siding Key
• Dave's Painting