Stretching your own canvas costs less than buying one ready-made, and you get to pick the exact size and fabric. Colin Mitchell of Opus Art Supplies walks through the whole job: slot the stretcher bars together, cut and tear the canvas, staple from the center out, and fold neat corners. It takes about half an hour once you have the tools. The result should sound like a drum when you tap it.
How to stretch a canvas: tools and materials
- Stretcher bars. Four bars that slot together, with a beveled edge that faces the canvas so the paint surface never touches the wood.
- Raw canvas. Cotton duck or linen, unprimed or primed.
- Canvas pliers. Wide jaws grip the fabric and lever it tight over the bar.
- A staple gun and short staples, about 3/8 inch.
- Corner gussets for larger frames, to keep corners square.
- Scissors.
How much canvas to cut
Add enough fabric on every side to wrap around the bar and reach well onto the back, plus a little to grip with the pliers. For standard 3/4 inch bars, about 2 inches per side is plenty. For deep 1.5 inch bars, allow 3 to 4 inches. Too little canvas means the pliers have nothing to grab. Too much leaves bulky corners.
Getting even tension
The first four staples set the tension for the whole canvas. One in the center of each side, opposite sides in turn. Check that the weave runs straight and parallel to each bar. Then keep working outward from the centers, always a staple on one side and then the side opposite. As you go, a faint diamond pattern appears in the fabric. That means the tension is even. Ripples or a sag near one corner mean that side needs more pull.
Primed vs unprimed canvas
| Canvas | Pros | Watch out for |
|---|
| Unprimed | Cheaper, you choose the primer | Must be sealed and primed after stretching |
| Primed | Ready to paint once stretched | Stiffer, can crack at the corners if folded too sharply |
Sealing and priming
Raw canvas soaks up paint and can discolor over time from the oils in wood or paint. Colin seals his bars and canvas with Golden GAC 100, one or two coats, then adds gesso. Unprimed canvas also tightens a little as the first wet coat dries, which pulls out any small slack.
Common mistakes
- Stapling all of one side first. The fabric skews and wrinkles.
- Corner folds facing out. They snag and can pull loose.
- Overtightening a primed canvas. It can split at the bar edge.
- Canvas loosens months later. Tap the small wooden keys into the inside corners, if your bars have slots for them, to spread the frame a little.
Ready to paint
Before the first brushstroke, follow how to prime a canvas. Then try blending acrylic paint or a simple sunset as a first painting. For raised effects, see how to use texture paste.
