Building the Frame
Preparing a canvas for paint begins with building a frame from stretcher strips. Stretcher strips are normally made in a tongue and groove pattern at the corners, allowing for easier assembly. The tongue and groove should snap together into ninety degree angles at each corner. For extra hold on the corners, dab a moderate amount of white or wood glue onto the tongued portion of the stretcher strips prior to snapping them together. Wipe away any excess glue that is pushed out. To ensure that the corners are a true ninety degrees, place the frame in a doorway, with one edge on the floor and another against the door-frame. Tap the side of the stretcher strip frame, gently, with a hammer. Rotate and repeat for each side of the stretcher strip frame. If glue was used, allow the stretcher strip frame to dry for 24 hours.
Streching the Canvas
The next stage in the process of preparing a canvas for paint is the stretching of the canvas. Lay the canvas out onto a flat surface, on the floor or a on a large table depending on the size of the canvas, and place the stretcher strip frame on top of the canvas. There should be two to three inches of canvas around the outer edge of the stretcher strip frame. Choose a side of the frame and apply downward pressure to the center of the strip with the lower part of your palms. Grasp the canvas with the thumbs and forefingers of both hands and pull it tightly over the back of the frame. Use one hand to hold the canvas and maintain downward pressure on the frame. Use a hand-held staple gun to place two staples, approximately one centimeter apart, on the side of the frame in the center of the strip. This will be Side 1. Go to the opposite side of the frame and repeat this process. This will be Side 2. Do the same on the remaining two ends. Returning to Side 1, to the right of the original staples, grasp the canvas as before and pull it over the back of the frame and slightly toward the closest corner. Hold the canvas and apply two staples to the side of the frame approximately one centimeter apart. Go to Side 2 of the frame and repeat the process. Repeat for the remaining ends. Return to Side 1 and, to the left of the original staples, pull the canvas over the back of the frame and slightly toward the nearest corner. Place two staples, approximately one centimeter apart, on the side of the frame. Repeat the process for Side 2 and the remaining ends. Continue this process of pulling and stapling, alternating between left and right until there are staples holding the canvas the entire length of the frame on all four sides. Once the stapling is finished, trim the canvas so that it is flush with the back of the frame. The canvas should be tight, like a drum, over the frame. If not, the canvas will have to be discarded and the process started over from the beginning.
Gesso the Canvas
The final stage in preparing canvas for paint is Gessoing the canvas. Gesso is a substance, similar to primer, that protects the canvas and the stretcher strip frame from the paint. Using a two-inch, house-paint brush, apply a thin, even coat of Gesso over the surface of the canvas and allow to dry. Depending on the temperature and humidity, the drying process can take 30 minutes to several hours. It can be tested by gently touching the surface of the canvas. Once dry, apply a second thin, even coat Gesso to the canvas and allow to dry. Once the second coat has dried, use 220 grit sandpaper and very gently, hand sand to smooth the surface. Any lingering dust may be removed by gently blowing across the canvas. The canvas has now been prepared for paint.
