How to Stretch an Art Canvas

"Nearing Utah", Oil on Panel, 6x6 inches

Jerry Lebo, 2007

I did a post a couple of weeks ago titled, "How to Make an Inexpensive Frame for your Paintings" which turned out to be popular. It was noted by The Artist's Magazine's blog, so a lot of people tuned in to that post. It seems that everyone appreciates a good DIY post, so to make it easier in the future, I have put a listing of my DIY posts on the right-hand side of my blog under the title "Do It Yourself".

Given all the DIY euphoria, I decided to do a post about how to stretch an art canvas. Yeah, I know what you're thinking--doesn't everyone already know how to do that? Well, I think you'd be surprised how many people don't. I remember teaching people how to stretch canvas when I was at the Washington Studio School and Holton-Arms School (where I was the visiting artist back in the 1990s and my friend Lee Newman still teaches). It is the type of thing everyone assumes every else knows, so no one takes the time to teach it. In my experience, even people who are painting regularly don't necessarily know how to stretch a canvas. I see a lot of people going into the art store and buying ready made canvases. I guess it is like frame-making and panels, why do it yourself when you can buy it at the store ready made?

In my mind, there are good reasons to learn how to stretch your own canvas. First, if you are traveling, stretching canvas can save you a lot of weight. You can take a mix of various stretcher bars and a roll of primed canvas or linen--and when you are done painting--simply un-stretch your paintings, roll them up, and take them home. You can even ship the bars and leftover canvas back home through the mail if you get in a bind. Try carrying 20 large panels on an airplane or in your luggage--panels are heavy--and they are cumbersome. The other reason to learn how to stretch canvas is that it is a quick and easy way to have something to paint on--in any size you want.

All said, in my experience, the most important reason to learn how to stretch a canvas is to save storage space in your studio. The method I am going to show you also allows you to un-stretch and store your paintings flat or rolled once they are dry. You can't do that with the pre-stretched store bought canvas--since they don't have enough overlapping canvas to re-stretch them once you take them off the stretcher bars. Also the quality of the pre-made canvas generally is not good--and they are typcially not very tightly stretched.

So let's get started. Here is what you need--some canvas or linen, stretcher bars, a tape measure, canvas pliers, something to mark with (pencil?) and a staple gun. I prefer the standard JT-21 staple gun, which is what they sell at art stores and some hardware stores. You don't want to get a staple gun that is too big or strong--since the staples will either not penetrate well or will be too big and possible weaken the canvas.

The first step is to put the stretcher bars firmly together. If they don't go together easily, use can a hard surface so as to have something to press hard down upon. Some people like to use a door jab to assist and keep the corners square--however, just because you use a door jab--doesn't mean they will be square--so you need to measure as well.



The corners should fit tight, like below, when all the bars are together.



Once you have all the bars tightly together, the next step is to make sure they are perfectly squared up. This is a two step process. The first step is to make sure the distance vertically and horizontally between the bars is consistent. Since you are usually not stretching a square canvas, this means the distance across each paired side should be equal. To check, measure the distance across one side at two points near the corners of each stretcher bars. I have used two measuring devices in the picture below to demonstrate where to measure, but you will only need one. The distance at two points near the corners--around where I have place the measures in the below picture, should be the same. If not, adjust the stretcher bars by pulling the appropriate end until the distances are equal. Repeat this process across the other pair of bars.



Once you have sides consistent, the next step is to make sure the stretcher bars are squared--that is, at 90 degree angles. The way to do this is to get the diagonal distance to be the same across corners (assuming the first step was done correctly). As per the below picture, measure the distance corner to corner across one side, then the other.



If the distances are not equal, the easiest way I have found to get them equalized is to place the frame on a firm surface and push the top stretcher bar sideways (not downwards) in the direction of the shorter side. For example, if the measurement from the left hand corner to the bottom right is shorter--push the top bar towards left. It doesn't take much of a change in the sideways direction to make a big change in the diagonal measure--so don't over compensate. If the difference in distance is less than an half inch, for example, a slight tweak to the left should be enough.



Okay, so if you have the stretcher bars squared up and equal distances apart--the next step is to fix them together so they don't shift while stretching the canvas. To do this, I put three staples across each of the four corner joins as in the below picture.



The next step is to mark out your canvas piece. I like to use a stretcher bar to do this. For some reason, the width of a stretcher bar is just the right size for the extra canvas you will need to ensure a tight stretch and to un-stretch and re-stretch the canvas later. The first step is to square up the frame to a straight edge of the canvas. In this case, I have used the lower edge, which I know is straight. Then I have placed the bar on the right side, to make the first line.



Once you have all four sides marked, you can go ahead an cut out the canvas.



Place the canvas face down on a clean surface and put the stretcher frame on the canvas. Make sure the side on which you have stapled the corners is facing up (towards what will be the back of the final canvas). To help center the frame, you can use a stretcher bar along one edge to guide you. Once centered, start by pulling up one side of the canvas and put a single staple in the center of the stretcher bar.



Once you have one staple in the middle of the first stretcher bar--move to opposite stretcher bar and use you canvas pliers to pull directly opposite your first staple. Once you have a tight stretch--put in your second staple.


Once you have two sides stapled, move to one of the unstapled sides and put another staple in the center of the bar. Once you have a single staple in all four sides, the canvas should have a nice diamond shape in the middle. If it does not--take the staples out and start again. This is the most important step and worth repeating until you get it right--otherwise the canvas in not going to be tight when you are finished.



Once you have a single staple on each of the four sides (and a nice diamond shape), go back to the side you put the first staple into--and (using your canvas pliers to get a good stretch) put a staple on each side of the first. Then move to the opposite side, and repeat. Then move to the other sides, and do the same. Do not put more than two staples on any side at a time--before moving to another side. It is tempting to do one side fully, then move to the next--but you will not get a good tight canvas with this approach.



For this tutorial, I am stretching an 11x11 inch canvas--so only took five staples per side to completely attach the canvas tightly. Here is what a finished side looks like once all the staples in place. Notice, i did not put the last staples all the way at the end of the bar--but left a bit of a space. This is to allow folding of the corners.


Once you have all the staples in place, turn the canvas face down again and make the corners. I have heard these type of corner folds called "hospital corners"--since I think this is the way they used to fold sheets. Basically, what you do is fold the corner of the overlapping canvas towards the center--and then fold the remaining overlapping material over. Once you ahve the fold nice and tight--put a staple across the fold to hold it down. The canvas should be snug against the corner.



Once all four corners are done, I like to put a staple on the overlapping bits of the canvas--one or two is usually enough--and will hold the canvas snug to the back. Here is a picture of what the back looks like with all the staples in place.


And here is the finished canvas--ready to go.



So, there you go, a quick tutorial on how to stretch a canvas. I have stretched canvases up to 30x30 inches using this technique. If you go larger that this, you will need to use a cross brace to keep the bars from warping--or use heavy duty stretcher bars.

Hope you find that useful. Off to the studio--it's time to paint.

All the best, sixtyminuteartist.