How to Stretch
a Canvas
What you need (if possible get this stuff from Utrecht
or Jerry’s and let them know you’re in this class):
- Stretchers
(not to be confused with strainers)—make sure they fit together snugly and
that opposite sides are of equal length, ensuring a proper rectangle
- Canvas*—make
sure you have at least 3 or 4 inches or so of extra canvas beyond the edge
of the stretchers.
- Scissors**
- Staple gun
**
- ¼ to 3/8 inch staples (my staple guns take JT-21
staples)
- Tape measure**
- Acrylic gesso (if you are using unprimed canvas)
- Sand paper
or sanding sponge*
- Canvas pliers (optional, but recommended)**
- house painting brush 2 inch (or so) **
- skinny flat screw driver and/or needle nosed
pliers; (for prying out errant
staples)*
- Stretcher keys
- Tack hammer**
*A heavy canvas drop cloth from
a paint store often does very well in lieu of “art” canvas—much cheaper, too!
** You may possibly share these
items with others
At the very least, you should
bring in your own canvas, stretchers, gesso, and JT21 size staples (they fit my
staple guns). You can borrow just about
everything else.
Directions
To start out, unfold or
unroll and lay out your canvas on a flat, clean surface face down. It should be cut large enough to comfortably
fit over the stretchers to the back inside edge. Fit the stretchers together to make the
desired rectangle (be sure that your rectangle has exactly square [90 degree] angles—don’t
stretch a trapezoid!).
After making sure that the
weave of the canvas is parallel to the stretchers, carefully fold the canvas
around to the back each stretcher and put a single staple in the center of each,
making a cross. The canvas should be “finger
taut” between the staples.
After making sure the
stretchers are still square (measure the diagonals), start from the staple in
the middle of each stretcher and staple down one side of the stretcher to the
corner while pulling the canvas finger tight (pull it tight enough to ensure
that the weave is still parallel to the stretcher). Do this on only one side of the center
staple. By working from the center to
one corner you will end up completing half of the stretcher. Do all four sides but make sure that you always
do the same side of the staple each time. When this is completed the staples will
resemble a pinwheel or swastika shape.
Now that the canvas is
halfway stretched, the tightness of the canvas becomes more important. As you work your way down the other side of
each stretcher, you will realize that you are now pulling against the part of
the opposite stretcher that is already stapled.
It is at this point that you can start to pull the canvas as tight and
evenly as possible (canvas pliers will become a welcome time saver and knuckle
protector). Work your way down the
unfinished side from the middle staple, ensuring that there are no wrinkles
between staples. Always work from the middle to the corners. Excess canvas can be dealt with at the
corners. Also do your best to keep the
weave of the canvas parallel to the stretchers.
Once you have finished all
four sides of the stretchers and after having made sure that everything is
still square, evenly taut (no wrinkles or dead areas), and passes the quarter
test, it is time to finish the corners.
The key to good corners is neatness and cleanness. There are several ways to do them cleanly,
and you may need to devise your own way, but I find that if you just make sure
that the visible fold goes down along the corner of the stretcher, the rest
will take care of itself—as long as it’s neat
and clean! There is no point in
doing a nice painting if your support is shotty, you know? Take pride in your handiwork.
Once the canvas is stretched
evenly with the corners finished cleanly, the canvas is still not ready to be painted
. . . it needs to be sized/primed.
Acrylic “gesso” is the simplest and most common way of sizing a
canvas. Brush the first coat on
liberally with a house painting brush, and sand it lightly after it dries
completely. Put at least one more
liberal coat of gesso on after this one, sanding between each coat, but do not
sand the top coat. It’s usual to make
the brush strokes parallel to the weave of the canvas, with each subsequent
coat being perpendicular to the previous one.
Also, be sure to gesso the side of the stretcher as well, both to
protect the weave and for a cleaner look.
Give the top coat of gesso at least an overnight to fully cure, and the
canvas is ready to use.
Eventually, no matter how
taut your canvas is when you stretched it; due to atmospheric conditions it
will relax and start to wrinkle or get wavy.
To make the canvas taut again, with a tack hammer lightly tap some
stretcher keys (little plastic or wooden wedges designed for the purpose) into
the slots on each inside corner of the stretchers. Working around the stretcher, give a few taps
to each key so that they slowly tighten up together. This will force all the corners to expand
enough to take up any slack that the relaxed canvas offers, resulting in
retightened canvas. Be careful not to
tighten any corner more than the others, as this will cause the canvas to go
out of square. Good luck and happy
painting!
This semester we will make 7
paintings (not including the color and approach exercises). Except for the first still-life, you are to
make them all on non-commercially produced supports, and at least one is to be
done on a stretched canvas. If you are
interested in planning ahead and buying supplies for all seven at once, here
are the size ranges you will need:
- (self-portrait): 16x20-24x30
- (landscape): 8x10-11x14
- (in class Abstract) minimum 18x24
- (at home Abstract) no size restrictions
- (in-class figure) 11x14-16x20
- (final project): no size restrictions
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