Round Strainer Frames
3/4″ strainers are made from a single layer of Baltic birch plywood and are available up to 36″. (Note that 1/4″ [6mm] staples or an air nailer must be used on the birch to ensure the staples pull in tightly).
Larger frames are made to be 1-1/2″ by adding an additional layer of fir plywood laminated to the back. This both adds greater stability and is also easier to staple into than the birch. (Staples longer than 1/4″ [6mm] may be used on the fir.)
When using shaped frames, we recommend that unprimed cotton or linen canvas be stretched first and then primed. The unprimed canvas is more flexible and can be pulled tight around curved edges without creating folds in the canvas. The photo above shows a round canvas stretched on a 60” diameter frame. The visible edge is free of any folds but the folds are quite pronounced on the back side of the frame. The thicker the frame, the more difficult it is to avoid folds in the canvas along the edges. For this reason, we try to keep most shaped frames to 1-1/2” or less in thickness.