Stretching Canvas

Stretching Canvas

Stretching one's own canvas can be very rewarding but involves a considerable amount of work and attention to detail. I have found it to be worth the trouble from a couple of standpoints, the first being the economic consideration. It is basically about a third of the cost to stretch your own canvas as compared to a commercial canvas of the same dimensions and comparable quality. The other consideration is, one knows exactly what went into making your own canvases. One might not be so certain about what kinds of materials have gone into something commercially prepared.

I buy cotton duck drop clothes from a national paint retailer. The last time I purchased a nine foot by twelve foot drop cloth I think the price was somewhere around fifty or sixty dollars. Not too bad for 108 square feet of 100% 12 pound cotton duck. I have to pay a little more for the ones that are made without any seams and they are not always available. The seamed drop clothes have two seams running the twelve foot dimension but most of my paintings will fit into those parameters. If I know I am going to be doing a really large painting I spring for the no seam items if I can find them.

The next step is to construct and put together the stretcher bars. This involves a table saw. I rip 2” x 4” 8 foot pieces of reasonably clear pine length wise through the table saw with the blade tilted at about 66 degrees off the bed of the saw. This gives me an angled cut which runs the length of the center of the two by four and I now have two pieces of stretcher bar material that have angled sides on the surfaces of the cut I just made and three other sides which are ninety degrees from their adjacent side. If you took a very simplistic symbol for a house, a little square with the triangle roof, and made a vertical cut right down the middle starting at the top of the roof and moving down to the middle of the base, you would have two pieces that looked like stretcher bar material from the end of the bars.

I then cut those bars to the dimensions of the canvas I want to create in a miter saw at 45 degree angles. They are cut in opposite directions on either side of a given stretcher bar with the tall side of the bar on the long side of those forty five degree cuts. An electric chop saw works great. For quite a few years I used an old antique miter saw that a buddy of mine gave me when he got an electric for Christmas. That was very labor intensive. I now have an electric miter chop saw and find it worth the investment. After making sure I have four stretchers, two of each dimension I apply wood glue to the end surfaces of two bars that I want to join. Clamping the two bars to a squared piece of 4” x 4” with adjustable carpenter clamps with each of the forty five degree surfaces butted up together I then use a power drill to attach the bars at a ninety degree angle with 2¼” sheet rock screws with the high side of the stretcher bars on the outside of the ninety degree angle. I find drilling pilot holes really helps to make sure the screws go where they are supposed to go. Now the joint is secured with wood glue and sheet rock screws. After affixing all four stretcher bars together in this fashion I have a squared rectangle which looks sort of like a crude picture frame. If on a table with the angled cuts facing up the outside edges of the frame constitute the highest ridges of the stretcher and fall away toward the middle of the stretcher at about 24 degrees.

The next step is to cut a piece of canvas which overlaps the stretcher by 4 inches on all sides. This will give me plenty of canvas to grab onto when I am actually stretching the canvas and stapling it onto the stretcher bars. I staple one overlapping side of the canvas to the back of the stretcher with an industrial staple gun which will accommodate ½ inch staples. This keeps the staples off the sides of the painting. I then go to the opposite end of the stretcher and pull the canvas around the back of that side of the stretcher bar with a pair of canvas stretching pliers and give it a good yank to make sure the canvas is stretched as much as possible and then staple that as well with about three staples an inch or so apart in the center of each stretcher. I then go to the adjacent sides and do the same procedure and then back to the original sides and add two more staples to each side of the already existing staples. I go around the canvas in this fashion until the canvas is completely stretched. At the corners of the stretcher bars I fold the canvas under itself as if I were making up a hospital bed and then staple all that down on the back of the stretchers to make everything secure. This particular way of stretching is called “Gallery Wrap”

It is now time to prepare the canvas with some kind of sizing which will protect the cotton from the acids in the oil paint. The traditional method for creating this layer of protection was to apply a coating of hot animal hide glue (usually rabbit) to the canvas which is prepared in a double boiler in quantities estimated to coat whatever canvas is going to be covered in a given session. When the glue cools it congeals and can not be used a second time. A more contemporary approach is to coat the canvas with latex based gesso. This seems to be quite effective. It is water based, can be applied right out of the container and dries in about a day. Since it was introduced into the art market about 65 years ago and has not really had the opportunity to stand the test of time we really don't know whether it will hold up over the course of several hundred years or not but canvases prepared this way seem to have held up pretty well thus far.

After the gesso has dried, a layer of primer paint, usually white oil paint (either titanium white or flake white which is lead based) is applied to the surface of the canvas and allowed to dry over the course of about a week. If a very smooth surface is required, this coating can then be sanded and another coat applied and allowed to dry for another week. Several coats may be applied in this fashion and sometimes the preparation of the canvas can take longer than the time it takes to actually execute the painting. It is an arduous process but one that pays off in the long run. Stretching and preparing one's own canvas is part of the process which involves a sense of pride in craftsmanship.