How to Stretch Artists' Canvas
After determining the required canvas size, for example, 24" x 36",
select the corresponding sizes of stretcher strips and make up a frame
by fitting together the mitered ends.
Check the squareness of the frame by measuring across the diagonal corners
fo that both measurements are equal. If bracing is desired for a larger
size, attach snugly with provision for later expansion.
Spread the canvas on a clean flat surface, primed side down. Position
the frame for best material yield, allowing from 1 1/2" to2" excess
for gripping and stretching, depending on the type of stretcher frame.
Cut out canvas segment.
Fold one side of the canvas over a short end of the frame, and tack
at the center of the strip, allowing for 1 1/2" - 2" excess.
Reverse to the opposite side, using canvas pliers to grip the canvas
in the left hand (for a right-handed person) with the frame resting
in an upright position, primed surface facing you.
With a tight grip on the pliers, pull firmly until a straight crease
is formed running from the pliers to the tacked end. With your right
thumb, insert the tack while maintaining plier tension at the top of
the crease, and tap in. A magnetic-head tack hammer will allow you to
pick up the tack with one hand and insert it faster, using the other
side of the hammer to tap in. When using a staple gun instead of tacks-and-hammer,
the left hand pliers function is unchanged, and the stapling method
Move to an adjacent side and follow the same procedure, pulling firmly
and tacking canvas to the frame at the center, creating first a triangle
crease and then a diamond crease in the canvas with the fourth tack,
at the opposite long side. Then temporarily tack canvas at each corner
on short side only. Work out from center of long side.
Move the pliers about 2 inches to one side, pull tightly, and tack to
the frame. Repeat for several more inches in both directions from the
center, then reverse to the opposite side and continue the process.
Pull out tacks from the corners of short side and tack or staple from
the center to the edges. Repeat the same procedure on one adjacent side
and then its opposite. Depending upon the size of the canvas, and entire
side can be tacked at one time, or for larger sizes, the canvas should
be rotated several times before it is completely stretched. A linen
primed canvs, particularly an oil-primed linen, will normally require
more closely spaced tacks as there is limited stretch to the fabric.
Leaving about 2 inches untacked at both ends of the inner sides, tuck
in the corners as illustrated and tack through the folded canvas into
the frame with exerting finger tension.
Fold the excess canvas to the back of the frame and tape or tack, to
allow for removal and remounting in the future. If the canvas is trimmed
flush with the back of the frame it will be difficult to remount properly
without reducing the size of the frame.
11. Avoid using pegs to take out wrinkles as this may throw the frame out of square, damage the canvas, or enlarge the stretcher frame so that it may not fit a standard picture frame. Restretch the wrinkled portion instead. The use of pegs should be confined to its proper purpose of mounting raw canvas for priming on the stretcher frame, after the initial sizing has dried.
12. On acrylic primed canvas only, small indentations and ripples may be flattened out by dampening only the affected area with a damp sponge and allowing it to shrink back to its original shape. However, always use care not to saturate the canvas, and allow it to dry completely in a well ventilated area. Large wrinkles should be removed by restretching the affected area, or the entire canvas if necessary.
It is relatively easier to stretch raw canvas than primed, but considerable skill is required to prime the canvas with a quality ground. It is also easier to stretch primed cotton and Polyflax canvas than primed linen canvas, as the linen fibers do not have much stretch. Oil primed (and in particular; double primed) canvas requires the most care in stretching, as there is practically no stretch, and it is not at all unusual to have to remove some tacks at wrinkled areas, Restretch and re-tack, before getting the canvas perfect.
Please note: DO NOT wet back of oil primed canvases.
Thanks to Tara Materials for the above information.
Copyrighted 1994 Fredrix Artist Canvas, Inc.