This is an expanded section on stretching canvas, canvas preparation, and using canvas stretcher bars. I have a few photo's to show you what kinds of problems you are likely to encounter, (on 90% of store bought canvas's), and how to correct the issue. I also have found an excellent video, both in the act of stretching canvas but in applying gesso afterward.
So lets get right to the point!
If you need a really enlarged picture, just click the picture to see it super-sized!
Now, do you see that staple the screwdriver is pointing at? It can cause you some real problems if you plan to stretch this canvas to make it tighter to paint on.
Why? Well look at the next 2 photo's. You can see the depth that the typical staple goes into these canvas's. Once they go beyond the first layer of wood, and catch the tenon, it will inhibit any movement of a part that needs to move!
You'll be hammering the keys till the cows come home, and your canvas will still not stretch! So what do you do? Don't get your nickers in a twist and read on.
Simply lift the offending staple. Not all the way, but about half way out in order for it to release the underlying tenon and allow the mortise and tenon joint to float (or move).
This photo (below) shows just the canvas stretcher bars without the canvas. The joint is butted together tightly.
This photo (below) shows the canvas stretcher bars with keys inserted and the bars separated (exaggerated).
This last photo shows the small amount of separation in a normally stretched canvas. It doesn't take much to really tighten the canvas like a drum!
Always work from opposite corners, and then tap down your lifted staples to lock your stretched canvas in place, and keep the corners from crinkling due the lack of staple support.
Now it's time to watch the video and then go out to play!
