Tips for keeping canvas stretched?

[Ryan Mack]

My first self-varnished and mounted canvases have been on display for about 2 years and I've noticed a pretty significant ripples in them as they've lost tension. Any advice on how I can best prevent or at least delay that in future mounts?

[dgberg]

Bars with keys is about the only reliable way. We use stapled and glued stretchers and it is always a problem especially with the larger ones. You can purchase some Tight'N'Up to spray on the back. Then use a hairdryer to dry it. It does work on the short term. You should find seasonal humidity to be the big issue.
In the spring and summer with higher humidity they should tighten up on their own. In the winter heating season is the worst. I keep my showroom heat at 50 unless a customer is coming and have almost no problems. In my house where it is considerably warmer they all get floppy over the winter. I just leave them go and over summer they tighten up again. The only thing I tell customers is to not hang them near a heat outlet. They really do not like that heat.
Keys solve the issue as you can pull it off the wall and tap them tighter. My production however is not set up for keyed strainers.

[John Nollendorfs]

Ryan:
First of all, stretch canvas when it's low humidity. It's counter intuitive, but canvas tends to loosen under dry conditions, and shrinks when it gets moist. Most canvas is a mixture of cotten and synethic. The cotton is what gives it the irregular texture we appreciate, and also expands and contracts with humidity conditions.

First thing you can try and do, is try spraying the back of the canvas with water, and see if that tightens the canvas enough to take out the ripples. If that doesn't work, you will just have to restretch it. Sometimes that can  happen just by removing staples on two adjacent sides and stretching and restapling. After that you might have to remove other staples and redo.

Good luck!

[Ryan Mack]

Bars with keys is about the only reliable way.

Sorry, this is a dumb question but what are keys? Are those the 45° corner pieces or something else?

[JeanMichel]

Sorry, this is a dumb question but what are keys? Are those the 45° corner pieces or something else?

No such thing as a dumb question. I just 'googled' and here is a simple description: https://www.thoughtco.com/how-to-use-canvas-keys-2578679

I occasionally print on canvas (24" wide by whatever) and have those stretched and framed by a competent framer. None have ever sagged in various environments. Think of this: how many sagging canvasses have you ever seen in a museum or gallery?

For smaller canvasses I have used the GO Frame kits, adding abundant staples and definitely not relying on the double sided tape of the kits. Those too have not shown any issues with sagging or warping.

[langier]

My framer tells me to use a water myst on the back of the canvas to help make it taught.

[jwittes]

I use this product when stretching larger canvases.  I've been happy with the performance.

https://gilmanbrothers.com/boards/mountcor-canvas-2/

[Ray Cox]

I use this product when stretching larger canvases.  I've been happy with the performance.

https://gilmanbrothers.com/boards/mountcor-canvas-2/

Thanks for the link. Very interesting "about" page on the website.

[PeterAit]

Are you stretching your own? I use Easy Wrappe from Breathing color. Easy to use and I have 24" wide canvases from 5 years ago that are still fine.