For a long time, I kind of dreaded stretching my own canvases. It is a great way to save money, but on larger canvases, it can be a pain. Part of the problem was I had a crummy pair of pliers. When I purchased a nice pair of pliers though, I didn't find them to be that much better. I have found a much better tool, with a small modification, for stretching canvas than the pliers that are sold in art stores.
Above are three kinds of pliers that I have tried. I have tried several others, including the very nice Dick Blick pliers, but these are those that I currently have.
1 - Canvas stretching pliers sold in art stores
2 - Duckbill Vise Grips for crimping sheet metal
3 - Another pair of sheet metal crimpers but these don't lock like the Vise Grips
The problem with the traditional canvas pliers (#1) is they can get tiring on large canvases and they slip if you don't keep pretty good pressure on them. The pliers on the right (#3) are nice because they have such large clamping surfaces, but still require you to apply pressure and keep one hand on them the whole time. The great advantage of the Vise Grips (#2), is that they lock, and once you have pulled the canvas, the weight of the pliers let's you let go if you need to, to tack or staple.
When you buy the Vise-Grips, they will have a square edge to them that is too sharp when stretching canvas. The corners and edges will tear the fabric, so you need to round the edges over with a grinder or Dremel with a grinder attachment. It doesn't take long and it isn't a precision adjustment, just enough to take the edges and corners off.
When stretching, invert the pliers so that the larger rounded part is on the bottom. This will let you use it to rock against the stretcher bar and help you get the canvas as tight as you need it. You can actually easily over tighten, especially with unprimed linen.
I hope that you find this useful. It has made stretching my own canvas very simple. Here is a link to the pliers I purchased on Amazon: VISE-GRIP Locking Sheet Metal Tool
Thanks for reading my post today!