Introduction: Old-School Stretch and Prime
Welcome to my studio. This tutorial demonstrates standard technique for stretching a canvas around a frame for the purpose of painting. It is similar in most ways to other sets of instructions you will see, but there are a few details that are not often used that I think are important. Most artists these days use staples to secure the canvas to the frame, but I want to encourage you to use tacks instead. In my opinion, tacks are not only a more reliable and secure method, but they also give the back of the painting a much nicer old-fashioned/hand-crafted look that you cannot get from a staple gun. Even though you cannot see them when the painting is on the wall, I am convinced that it makes the artist paint better knowing that there is just a little extra care involved in the process. The recipient of the art will also appreciate it. It really makes a difference. Its a spiritual thing as well as practical, and if that's not enough to move you...its just cooler. Second, we will be using rabbit-skin glue to prime the canvas instead of gesso. I prefer it to gesso because it is easier to apply, and has a more pleasing/earthy tone instead of stark white. I almost always put a thin layer of acrylic paint over the primer to tone the canvas anyway, but it still looks better than gesso. To me, rabbit skin glue also provides a better tooth for the paint. I would also encourage you to make your own frames, but that's for another discussion.
For the stretching part of this process, you will need: a frame (make it a size your are comfortable with, but as big as possible), canvas (I like 12lb, but some people like thinner 7lb or thick 15lb...its up to you), tacks (5/8"), scissors, a tack hammer with a magnetic end, a screwdriver (for popping-out tacks that fail to cooperate), and calipers. If you have a friend around to hand you the tacks and hold stuff, that's nice too.
Place your frame on top of the canvas with the front-side down. Make sure that there is enough canvas on all sides to wrap all the way around the back before you cut.
Secure the canvas in place with a single tack in the middle of each bar. Do not hammer the tack all the way in, as you are going to remove it in the next step.
Stand the frame up against a solid wall, and remove the top tack. Pull the canvas down with the calipers and then hammer it back in. Be sure to take advantage of the magnetic end of the hammer, as you only have two hands (I assume). You can hammer them all the way in as you go now. You should not pull hard on the canvas this time around. Just pull hard enough to stretch it smoothly against the frame. Next, put in a couple more tacks in a line toward the corner, but do not get too close to the end, or it will not be possible to fold the canvas properly later. As you pull with the calipers, keep your eye on the grain of the canvas. It should be in a nice straight line along the edge of the frame. If it is not, there will be a warping appearance to the canvas. Smooth the canvas along the top of the frame before every pull with the calipers.
Turn the frame 180 degrees and do the same thing to the opposite side. Make sure you move outward in the same direction (to the right here). Then do the other sides the same way. It should look like this at this point with half of each side secured, and each half side with tacks alternating with half sides without tacks. It is important to do it this way, so you get a nice, even stretch.
Now go through the same process on the other half of each side (going to the left now). Make sure you work opposite sides, and not in a circle. You will need to pull harder on the calipers this time around, but keep your eye on the grain of the canvas as before. You will need a lighter touch if you prefer a thinner canvas to avoid any warping of the grain. Please note that there are only five tacks on each side, and plenty of room to work the corners.
Folding the corners may take a little practice. Put a tack higher-up on the side to secure the edge. Lift the canvas up on the top side, and make an indentation with your finger. Then, pull the top down smoothly along the top, and put in a few tacks to hold it. Make sure when you fold the top down that no canvas hangs over the edge of the frame or it will not look good. You may need to re-fold the top a few times to get it right. Often, you just need to make your indentation a little bit further from the corner to fix it.
Here is the finished (unprimed) product. As you can see in the photo, I did not cut the canvas straight, but I made sure the grains of the canvas all line-up along the edge, so it is all square on the front side.
Applying the rabbit-skin glue is next. I doubt its made purely from rabbits anymore. Its just gelatin with some other stuff in it. I prefer Gamblin, but there are other brands out there that I'm sure are fine to use too. You need a hot plate (or stove) an old pot that you will never use for food again, a utility brush, and a spoon.
Bring the water to a rolling boil, and then turn off the heat. Add the rabbit skin glue a little at a time and stir it in. Do not dump too much in at once, or it will clump, and you will never get it all mixed up properly. Keep adding the powder until it starts floating on the top. That means there is enough dissolved in the water already. The mixture should be cloudy, and a little thicker than water. Over time, you will find a thickness that you like to work with.
Start applying the glue in the corners first, and then along the edges. Finish with the middle. Be careful...the mixture is very hot. I like to use rabbit skin glue instead of gesso because it is a hot liquid, and sinks into the fibers of the canvas immediately, and does not need any touch-ups. In fact, you should apply it to the canvas quickly and evenly without going over the same spot too much. The glue begins to cool and dry right away, and you will ruin the texture if you over work it. Let it dry overnight before painting on it. You will also find that rabbit skin glue stretches the canvas tighter than gesso does. Some people like to smooth it out with a fine sandpaper after it dries. I am not among them. I like to leave the extra tooth. What goes on top of the primer is up to you...happy painting!!!