I usually buy stretched canvases from the local art supply store, but my next project requires a large size that is not in stock. It’s the perfect opportunity to learn how to stretch a custom canvas for fine art!

This project isn’t very difficult, but it is much easier with the correct tools, and a little understanding of what might cause problems for your painting in the future. To start, get your tools together:

Building your frame:

  • stretcher bars in the correct length and width
  • measuring tape
  • right-angle ruler
  • hammer or mallet
  • staple gun with staples to attach wood

My frame is 22″ by 50″. I also selected the gallery-sized stretcher bars, which are thicker than the standard stretchers, for two reasons: first, I thought a heavy duty frame would resist bowing in the middle when I stretch the canvas, and second, it is possible to show paintings on gallery stretchers without framing them. I like to have that flexibility!


You will need 4 stretcher bars, which are beveled with a raised outer lip to hold the canvas away from the support, and cut at 90 degree angles with interlocking teeth at each end.


Line up the corners, and begin sliding them together as best you can. You will probably need a hammer or mallet to make them fit properly. When you have 3 sides together, check your right angles and measure the diagonals (they should be identical in length).


Before you add the 4th and final side, staple the pieces together at each corner on both sides of the frame.  I found it was easier to begin with 3 sides well joined, and then add the last side without making too make more adjustments.


When the sides are all together at right angles, check that the corners are not too sharp, and make sure the joining teeth are not sticking out too much. These could poke through the canvas or cause a tear. Use sand paper to remove any sharp points or rough edges.

Although these stretcher bars are convenient, they are not always perfect. Mine all lay flat on the table, but when they were joined, some tension in the corners caused the frame to twist a bit. I don’t have a solution to this problem, except to check the bars in the shop to make sure they are the same wood, and the same cuts. My bevels were slightly different in shape, suggesting that a different machine could have made the different sizes, so that the joining teeth might have been made differently. If you are pickier than me, this might drive you crazy enough to return the stretchers and try new ones. I decided to keep these, and place the best end at the top of the painting. I am too excited to start this painting to waste time driving back and forth to the art store!

Finally, check your corners and diagonal measurements again.  If you are happy, staple the last bar into place, use your hammer to set the staples all the way in, and get ready to stretch your canvas.

Please watch for Part 2 and Part 3, which will describe the process used to stretch a custom canvas for fine art and priming your canvas. In the meantime, here is a Pinterest-friendly preview of this tutorial.