Stretching A Large Canvas

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Shayla

Shayla

WOW Framer
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We're gallery-wrapping a 67 x 67" unpainted canvas onto a stretcher frame, and it's bigger than most we've done. I know some folks here do giant ones, but even this feels big to us. Because we're in the habit of pre-stretching and tacking overnight, we did that, and changed our method partway through. At first, it was canvas-side up and we tried using our stretching machine, planning to hand-stretch what the 60 bite didn't reach. But at this size, the heavy canvas sank down between the empty spaces between the bracers so much, it was a problem. We covered the table with foam core, turned the whole thing over and did our pre-stretch with the canvas lying face down on the foam core, the stretcher on top, and pulled the canvas up to stretch by hand with pliers. That solved the sag problem, but it seems we'll have to do the whole final stretch by hand, too.

It got me thinking about how people stretch. Our stretching machine hangs off the side of a table, so when we stretch, the canvas and its frame are lying flat on the table, with just the side being stretched hanging out over the machine. We like this, but to try it on something with a big canvas, it seems that we'd have to shim under every empty space in the middle of the canvas to keep it from sagging so much that it interferes with the stretch. A printer in town has his stretching maching oriented so the canvas and its frame are hanging sideways, perpendicular to the floor, and he staples across the top edge. But he doesn't do gallery wraps.

Do you stretch with your canvas flat, right side-up, upside down, or perpendicular to the floor. Also, if it's a good idea to pre-stretch canvas prints with tacks overnight, isn't it also a good idea with unpainted canvas? Thanks for any notes.
 
Sounds like way too much stress.
If it's decent quality, primed canvas, just lay canvas face down on table, stretcher frame on back and tack centers, then corners, then work out from centers.
 
CB Art & Framing said:
Sounds like way too much stress.
If it's decent quality, primed canvas, just lay canvas face down on table, stretcher frame on back and tack centers, then corners, then work out from centers.
Click to expand...

Not stressing; just describing. Thanks for your note. We ended up leaving the tacks in three sides and stretching it face up lying flat on the table, with the one untacked side centered in our machine, leaving about three inches unstapled on the sides. After doing that to opposite sides, we then turned it upside down on a layer of foam core and used framing pliers by hand in stapling the corners. It looks good.
 
Is it just canvas or primed? In either case I'd be tempted to lightly mist the back as I stretched it too.
 
Thanks, Ernesto! Dave, it's already primed. I thought about misting it, but didn't know if that would be wise. After a whole passel of strainer frames, which have worked great, this is our very first stretcher. It's the metal/wood combo from Richeson, and they've been very helpful. We took heed of someone's note wishing they'd added the Masonite corners, so we plan to do that tonight. Couldn't figure out how to put them on without it looking awful, until they clarified in a call that the corners screw into the metal interior supports, not over the back of the folded canvas.
 
The masonite corners are only used during the stretching process to keep the corners square and closed. Once you get most of the canvas stretched, you remove the corners and finish the job. They serve no purpose after the canvas has been attached.
The beauty of any stretcher system is that you don't need to get fantastic tension while doing the actual stretching. The keying provides that additional tension. Remember to shim out the cross bracing as well so the tension is even over the entire surface of the canvas. The plastic hardware the holds the ends of the cross bracing has a slot for the set screw, but i like to add shims cut from various thicknesses of mat board to the end of the braces so the set screw isn't the only thing holding the brace in place. BTW, the screws that come with the system should be replaced with some that are a bit more robust.
 
Just be cautious not to rely too much on the keying system to finish the job as it is likely that same system will be needed down the road as the canvas relaxes, as it will over time. If you have relied too much on keying instead of proper stretching in the first place, you won't be able to key it out in the future and it'll need to be re-stretched.
 
Love these notes. Much appreciated.
 
We have a stretching machine, but I don't use it.
I can do better stretching old school by hand and I'm pretty fast after stretching 100,000 or more canvases over the years...:confused:
I stopped counting long ago.
I am the stretching machine....:rolleyes:
(pay no attention to Iman, topless in the picture to the upper left in the shot..:eek::D)
FullSizeRender.jpg

Gonna' have to grow some longer arms...:rolleyes:
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Neil, if the Energizer Bunny ever took his costume off, I bet you'd be what climbed out. You sure do get a lot done.

For this project, we've found our way from z-bar to Z-Clips, which seem to be sturdy little Mini-Me's thereof. Richeson recommended them, and it looks like they're great for hanging the aluminum part of the bars from. How big do canvases have to get before you talk to your customers about their walls needing to be flat? It seems like, even if a wall wasn't flat, a person could just shim behind a clip on one side. We're thinking of putting metal shims behind the Z-clips, anyway, because her thick canvas, even though we made it as flat as we could, still adds 1/4" in back at the corners. And in case I forgot to mention, it's a gallery wrap.
 
I sometimes use washers to offset Z bar.
Do Z clips lock? if not I would be a little wary of customer moving canvas left or right on the wall and it slipping.
It's pretty easy to remove most of the extra canvas in the corner folds and back to avoid "bulge out".
NOTE: I only cut blank or inexpensive wall decor canvases this way.
 
CB Art & Framing said:
I sometimes use washers to offset Z bar.
Do Z clips lock? if not I would be a little wary of customer moving canvas left or right on the wall and it slipping.
It's pretty easy to remove most of the extra canvas in the corner folds and back to avoid "bulge out".
NOTE: I only cut blank or inexpensive wall decor canvases this way.
Click to expand...

That reminds me of something else. Dirk asked if it's best to use Z-Bar (or clips) at both top and bottom, but these combo bars only have 5/8" of wood at the bottom, and the aluminum is inset, so I'm not sure how it would work. I know framers sometimes do that with heavy things, though. (This is big, but doesn't weight over 30 pounds, and likely much less). Isn't there a thing about, when you use Z-Bars at top and bottom, keep the bottom one from bearing any weight, so it just serves as a loose holder, as otherwise, it would mess up the top one?

About the folding. On every gallery wrap prior to this, we've made a cut in the corners, but that was with strainer frames. With this, it seems that, if she ever has to tighten it, that could cause problems, so we folded it keeping all the canvas. I have photos, but I'm at work, and they're at home.
 
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