A canvas mounted on masonite stays flat and tight.
Painters usually prefer canvas as a painting surface. Because canvas is a fabric, it does not hold a shape unless you mount it. Most artists stretch canvas on a frame of stretcher bars, but this can be difficult since the canvas must be stretched tightly and evenly across the frame.
A popular alternative to stretcher bars is to mount the canvas on masonite (also known as hardboard), because masonite will hold its shape for quite some time. Some painters like to paint directly on hardboard, but this affects the paint flow and gives the finished work a different texture.
Instructions
1. Place the masonite flat on the ground or on a table, smooth side up. Dip the brush in gesso, and spread the gesso evenly across the masonite. Start with one short vertical stroke in the center crossed by a horizontal stroke. Work outward, alternating vertical and horizontal strokes until you reach the edges of the masonite. Cover the entire board with one to two layers of gesso. Pay close attention to the edges and corners to make sure they're covered.
2. Place the canvas on the board while the gesso is wet. Smooth out any bumps and wrinkles with your hand or a flat, blunt object. Lay heavy books (or other weighty and flat objects) on top. Place wax paper between the books and the board to prevent gesso from getting on the books. Leave the board for a few hours until it dries; lightly press your finger to the surface to see if the gesso is still wet.
3. Use a razor blade to cut away the excess fabric. Hold the side of the blade against the masonite's edge to keep your hand steady and cut straight. Be careful around the corners.
Another option is to paint gesso along the edges of the masonite's back and fold the canvas over, so that excess fabric adheres to the back.
