Step-by-step guide on how to assemble canvas stretcher bars

Canvas bars, DIY Canvas framing -

Step-by-step guide on how to assemble canvas stretcher bars

This guide was specifically created to help you with the assembly of your stretcher bar set, which you can purchase on Etsy. The good news is, you won't need any tools to put the bars together! However, you will need a staple gun to stretch the canvas on the bars. And, if you want to make the process even easier, you might consider getting canvas stretcher pliers - they're a great addition and will simplify the stretching process for you.

Assembly of canvas stretcher bars

For best results, you'll want to find a flat surface that's bigger than your stretcher. A sturdy table is ideal, but if your stretcher is too big to fit, don't worry - a floor surface will do the trick.

Canvas stretcher package and what is included

  1. Unpack the stretcher set. You will get the following:

    • Stretching bars (4 items)
    • A brace/cross-braces (will be added automatically on 40+” long bars)
    • Corner keys (2 keys on each bar or brace)
    • Set of hungers

  2. Align bars and braces.The set was put together for a quick "test fit" on my side to make sure everything is in order. To help with the assembly process, I've marked each corner with a number on the front side of the frame so each bar has its designated place in the set. Just keep in mind the numbers are located on the front side of the bars and will be hidden once the canvas is stretched over. So, when assembling, make sure to put the bars on the back to see the numbers easily.

    Align all bars

  3. Connect joints. To assemble your stretcher bars, simply join each corner one by one following the marked sequence. Just align the tenon with the mortise and give it a firm push until the 45-degree lines connect. Start with the corner number "1," then move on to "2," "3," and so on. The second end of the braces will be connected only when the connected bar almost gets its place.

    Connect bars together and get assemble canvas  stretcher

  4. Adjust corners and geometry. Now that you have the frame roughly assembled, make sure all the corners are adjusted properly. Check if the bars are perpendicular to each other and the corners are snug with no gaps between the 45-degree lines. Simply hold the stretcher vertically and gently turn it around to check each corner.

Canvas wrapping

Staple the canvas to the back of the stretcher bars: Start in the center of one side and staple the canvas to the back of the stretcher bars. Make sure the canvas is taut but not stretched too tight. Then, staple the other sides in the same manner, making sure to pull the canvas taut and even as you go. Trim the excess canvas from the back, being careful not to cut too close to the staples.

Applying Corner Keys

The corner keys help achieve the desired size and add extra tension to the canvas if needed. The frame is slightly smaller than the requested size (-⅛"), but this is intentional to make the stretching process easier and allow for further tension adjustments. Canvas can lose its tension due to various factors (such as the brand, priming, type of painting, temperature, humidity, etc.) after when you stretch your canvas as a drum the next day, it will be just okay, and that is normal.

Use the cornet keys after the canvas was stretched on the frame

  • Instal keys. Just slip the keys into their slots and gently push them in place. They should stay securely in place as you move the stretcher around.

  • Enforce the Keys. For best results, make sure to apply pressure to the keys evenly and with precision. Each key should be pressed with the same amount of force. Gradually increase pressure, being mindful of the gap between the bars growing evenly on all four corners. The final step is to adjust the brace/cross-braces. Gently press the keys until both sides are straight, keeping in mind that pressing one key on the brace will affect both sides.

  • Secure the keys. To keep the keys securely in place over time, you can attach them to the bars with staples or a tiny drop of glue. This will ensure that the keys don't slip out of their slots due to natural seasonal wood movement.


Hanging your canvas is easy! The kit comes with two hangers, but you can use only one if your frame is small, or you can use your own hanging system with metal wires. To attach one hanger, just find the center of the top bar and screw the center of the hanger to the center of the top bar. If you want to use two hangers, simply make two marks on the back of the top bar at equal distances from the sides, then screw the hangers there.

1 comment

  • debbie

    These bars are the best! They are sturdy and the way he puts them together makes it a snap to assemble. This is the first time I’ve ever done stretching and it turned out lovely. I highly recommend this product!

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