To comfortably stretch a canvas over a strainer frame having 2 cm thick bars, a canvas margin of about 4 to 5 cm will be needed for sufficient gripping.  The canvas is firmly gripped with with a pair of canvas pliers, pulled, held in position,  and then stapled in place, as shown in the image here. If the stretcher bar is thicker, add this extra thickness to the above, recommended thickness. The margins of the canvas should have at least this width of all four sides of its sides. This goes for all canvases, whether gallery-wrapped or not. This margin width will allow for the wrapping of the canvas around and over the four sides of the stretcher frame bars. All for canvas margins must be pulled tightly and stapled evenly all ...