If you look down the length of this bar, it is warped. (See the slight curving to the left?) A painting stretched on this bar will not sit flush against the frame. Sometimes you even see warped bars in the stores, so it is always good to hold them up and check. Also, there was another problem:
See how where the two edges meet, it is not level? The canvas will form a pucker here that no amount of stretching will be able to smooth out.
Well, those are problems of having to use mail order and not being able to see what you are getting, but now I live in an urban area and can just go out to the art supply store. Yea!!! So, I went to the Dick Blick store.
This was the sign at the entrance to the Dick Blick store. Food for thought.
Well, they had 19," but no 15" bars. However, the extremely nice clerk gave me a list of all the art supply stores in the area! So I went to a small store in Berkeley, Artists and Craftsmans, where they had some very nice, good quality bars, just what I needed!
See the difference? This is straight!
This is level, at least on the outer rim, where the canvas will be touching.
Okay, so I assembled the stretchers by tapping the edges together, carefully, with a hammer. Now it's important that the stretcher be square. So, here I am pressing it against a door frame to square it up.
This, of course, presumes that your door frame is square. If you live in an older house that has settled, it may not be. When I was in my previous house, I had to measure corner to corner, to square it up. Otherwise all my paintings would have been parallelograms!
Measure across each corner diagonally, they should be equal. Sorry about being so long-winded. And there's more!! But I'll save it for the next post.