Stretching a canvas ...
… is easy. You take four planks of wood, make a rectangle and pull the canvas over it. (Or pay framing stores a lot of money to do it for you…).
Before you get frustrated starting from scratch get ready made heavy duty stretcher bars (best & cheapest:Utrecht Art Supplies). Their ends fit together so precisely that you don´t need glue or nails. Asembly time for the perfect rectangle: 60 seconds.
Ideally use stretching pliers (see photos) for the next step. Grab the canvas and pull against yourself. In the beginning stretch just enough to make it semi tight. Be willing to take out staples and re-stretch, so don´t push the staples in all the way.
For the second round, start in the middle again and this time, go tighter with the staples on the longer stretcher bar. Leave 3 inches between each stape. Then do the other long side. Now you can really pull with those pliers.
Only when you are done with all four sides, approach the tricky task of making the corners look nice & tight. My method is to fold them on the short stretcher bar side and put as much of the canvas that will fold onto the back of the stretcher bar as is possible.
Voilá. This should take 15 to 30 minutes, depending on your learning curve. Use your index finger in the middle of the canvas to feel the tightness. If it almost feel like a drum then you´ve done a great job. My estimate: you´ll need to practice on ten canvases before you start to do a decent job, and after the 20th canvas you can do it in your sleep.
Material cost for a 70 x 44 canvas with Utrecht stretcher bars: 35$. Staples are cheap, obviously. The staple gun will pay for itself soon if you compare it to any framing store. And, best of all, it is fun and gives you that wonderful sense of having accomplished something with your own hands.--Tomas Loewy