Questions on canvas and stretching canvas

I’ve got some raw canvas and stretcher bars that I’d like to use.
I understand that I should prime the canvas before stretching.  I’m using acrylic gesso.
I notice the prestretched canvas at the store actually staple the stretcher bars at the corners.  Shouldn’t the stretcher bars be free to move and “tightened using those keys in the corners?
also instead of staples should I use tacks?  And is it best to tack from the side or in the backside?
lots of questions but I figure if I’m going to try this I ought to go about it the right way.


  • Some people staple to the sides, others to the back. I don't think it matters but if it's big modern painting that won't have a frame you would staple at the back. I find it easier to staple at the back with the canvas laid flat and face down on the table. I staple the canvas at the corners but I don't staple the bars together.  If you get an even all over stretch you won't need to adjust the keys much. 
  • dencaldencal -
    edited May 2020

    Advice based on theory, not practical experience, suggests preserving the ability to key the stretcher bars at some later date. Linen, polyester and cotton fabrics may get a little limp and saggy in humid weather. Left untreated at the back allows the fabric to perform like a sponge in wet/dry cycles.  The cyclic movement is not just an aesthetic thing, the dried and hardened paint will not tolerate the expansion and contraction over decades.

  • @dencal I’ve seen the backs of framed canvas covered with foam core or brown paper.
    Are you saying leave the frame staples and add a backing to reduce exposure to humidity?  Or are you saying also coat the back of the canvas?
  • Thanks @tassieguy on the staple comments. 
  • GTO

    The majority of cracking in paint surfaces is caused by temperature and humidity effects on canvas and stretchers. Foam core and brown paper helps but mainly keeps dust and insects out. If you want. paintings to last longer than you then priming the back of the canvas and the stretcher bars is good practice. Alternately, maintain the environment within Smithsonian parameters
    At the Smithsonian, the current environmental guidelines are 45% RH +/- 8% RH and 70o F +/- 4o F for exhibitions and storage spaces. (Mecklenburg et al, 2004) This simply means it is acceptable to be within a RH and temperature box bounded between 37% RH and 53% RH and 66o F and 74o F.
    At present the RH here in Perth ranges 40 to 99% daily. Temperature 30 to 113 F over the year.

    I switched to aluminium composite panels to avoid canvas completely.

  • No worries, @GTO.
     I forgot to mention that canvas pliers (if you haven't got them already) will make your job much easier. I didn't know such things existed until I found DMP.   :)
  • Thanks @dencal  what do you think about applying primed canvas onto Dibond?  I’ve thought about using goto Lineco glue to do that.  That way I’d have the canvas surface but the firm Dibond backing.
  • Yes. Thanks @tassieguy I do have canvas pliers.  But am not sure about how to apply the correct amount of pull (taughtness).
  • edited May 2020
    If it starts to rip (you'll hear it and feel it if it starts) then ease off. You'll soon get a feel for it. It should be tight enough that it doesn't yield under ordinary brush pressure. You can adjust  the keys at any time if it needs to be a bit tighter. I am the most non-handy guy on earth but I love stretching canvas now. And if a painting is a flop I can re-use  the stretcher bars for another painting.   :)
  • Ha!  I like like that.  If it rips...back off.
    what I am hoping to manage is keeping the weave of the canvas straight as I stretchy it.  Maybe stretching is too strong a word.
  • edited May 2020
    BTW, I have found that ordinary linen tears more easily than high quality cotton canvas. I bought a roll of linen once that cost me $700 but won't do so again unless I get rich and famous and can afford the best.  The oil primed linen I bought was more brittle/less elastic than the heavy grade cotton canvas I now use. 
  • @tassieguy What I have is a five foot roll of Fredricks cotton canvas.  I’m wanting to do a larger painting, probably not from life but I haven’t decided yet.

    BTW... sometimes it boggles my mind that we can communicate back and forth like this from half way around the world... 
  • edited May 2020
    Yes, it's amazing. When I was a kid in rural Australia we didn't even have a telephone. The only communication was by post. It's a different world. I like it.  :)

    I think Fredricks is a quality canvas so you should be ok. 

  • Well, I stretched a canvas. 36 x 24 inches (92 x 61cm).   I used pliers for part of it.  I used staples instead of tacks.  I primed the canvas first with three coats using a roller instead of a brush.  The primer was acid free titanium white acrylic gesso.  It was a creamy thickness, a little heavier than coffee creamer.  When I finished priming I held the canvas up to the light and made sure I couldn’t see any light or pinholes through it.  But after I stretched it I could see some pinholes so I added some primer on the back side too.  I gave the surface a light sanding to knock down any little particles that would show up when painting.
    I did remove the staples that held the stretcher bars at the corners and I made my own wooden keys so I could stretch it tighter using the keys.  I had to cut a new cross bar though. I’m glad I did because then I made it fit a little further away from the back of the canvas so I wouldn’t press up against it if I pressed too hard with the paint brush.
    I brushed some Holbein foundation mixed with some burnt sienna and some gray to get a mid tone.  When I brushed the foundation on I made sure I had the lighting in front of me do I could see any particles or brush hairs left on it when brushing.
    While I was at it I also glued a canvas 11x14 inches (28 x 36 cm) onto a Dibond board using Lineco acid free archival glue.  I used a printers ink roller to roll out the bubbles under the canvas. 
    All told it all as a bit of work but satisfying.  I can see where good stretcher bars can make a difference.  Some if my older canvases have heavier grade stretcher bars.
    Now I just have to come up with some subject to paint.  
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