How to Stretch a Large Canvas (Larger than 24"x36")
Stretching your own canvas can be much more economical than buying premade ones, especially when you want to start making larger surfaces. Premade canvasses and stretcher bars start getting pretty pricey when they're bigger than 36”—not to mention that they're flimsy and warp easily on top of it. In this tutorial, I'll show you how to make your own custom stretcher bars and construct a large-scale canvas that can be easily disassembled for traveling and shipping.
Never stretched a canvas before? Check out my tutorial on stretching small canvasses before you tackle the big guys, and practice, practice, practice. http://katmannel.hubpages.com/hub/How-To-Stretch-a-Small-Canvas
Stuff you'll need:
- 4 pieces of pine 1x3's (1x2's are also acceptable if you want to reduce the weight of your canvas, but be warned! They are thinner and therefore warp more easily; my preference is 1x3's)
- 4 pieces of quarter round the same length as your 1x3's (pieces are also acceptable, but it will be more difficult to construct)
- One bracer for every 3 feet (example: if your canvas is nine feet long, you need three bracers to ensure stability; make sure they are the same length as the shorter measure of your shorter 1x3's so they will fit inside of your frame...this will probably make more sense later)
- Right triangles cut from ¼ inch plywood (one to reinforce every corner you create, including inside the bracers)
- Wood glue
- Finishing nails (and a hammer)
- Spring clamps and strap clamps
Make your own stretcher bars! Take your 1x3s and lay them flat. Apply wood glue to your quarter round. Place the quarter round on a three inch side with the flat edge facing outward and the rounded side facing in. Use finishing nails to attach the quarter round more permanently; make sure the flat edge of the round is flush with the 1x3's edge. Try to insert your nails far enough down the curve of the quarter round that, when your canvas is stretched, the nails will not show through the canvas (this could puncture your canvas, and that's never good). Use spring clamps to secure the two pieces together while they dry.
Once your bars are dry, use a chop saw to cut the edges in 45 degree angles and cut your bars down to your desired lengths. Pay attention to what you're doing; each bar should have complementary angles with your quarter round on the outside. Also be careful to make a clean cut, as hesitating can cause your quarter round to split. Measure twice, cut once! (You can also pre-cut your 1x3's and quarter round to the same lengths and then glue them together if you find this easier).
Pre-drill two holes in each of your corners for screws—one hole going through one bar and into the other, and the other hole perpendicular so it does the same through the opposite bar—and then drill in screws. If you have no need to take apart your canvas frames, you should also secure these corners with wood glue. Wood glue is surprisingly strong, so if you think you would ever need to take them apart, make it easier on yourself and forgo the glue. Use a T-square to ensure that your corners are square.
Cut bracers so they fit inside your frame, parallel to your shorter lengths. Place them evenly throughout your frame, again, using one for every three feet as a general rule. Make sure there is a bracer in the center of your frame. Pre-drill holes diagonally from the bracer into your bars and drill in screws. Again, use glue if you do not need to disassemble your canvas.
Use finishing nails (and glue if, you guessed it, you don't need to take your canvas apart) to attach your right triangle plywood pieces at EVERY corner. Attach them back to back at bracer corners. Attach these on the side of your frame with the quarter round; this ensures that the back side of your canvas will lay flat against the wall, and the quarter round will clear the edges of the triangles while you paint. Use strap clamps to secure your frames until they are dry. One strap clamp along each bracer works pretty well.
Your XL frame is done! Wrap your canvas the same way you do smaller canvasses; please see my article “How to Stretch a Small Canvas (24”x36” or less)” for more detailed instructions. http://katmannel.hubpages.com/hub/How-To-Stretch-a-Small-Canvas Pay attention to the rule of stapling three staples along your longer sides to every one of your shorter sides. This will make your life much easier.
Now you may want to gesso your canvas. Stay tuned for my upcoming article on how and why to gesso your canvas!
Tips and Tricks
If you disassemble your canvas, draw a schematic and label your pieces accordingly. Though many of your pieces will be cut to the same lengths, it will still fit the best in its original order. This will also make the lives of gallery curators and buyers easier should you need to ship your piece.
If you want stronger connections between your pieces and have access to a few more power tools, using a biscuit joiner to create biscuit joints is a great option for creating extremely strong bonds. You will not be able to get these joints apart short of using a hacksaw, so if you want the highest possible stability in your canvasses, this is your best option.